Nitrogen(N)doping has been widely adopted to improve the light absorption of TiO_(2).However,the newly introduced N-2p states are largely localized thus barely overlap with O-2p states in the valence band of TiO_(2),r...Nitrogen(N)doping has been widely adopted to improve the light absorption of TiO_(2).However,the newly introduced N-2p states are largely localized thus barely overlap with O-2p states in the valence band of TiO_(2),resulting in a shoulder-like absorption edge.To realize an apparent overlap between N-2p and O-2p states,charge compensation between N^(3-)and O^(2-)via electron transfer from oxygen vacancies(VO)to N dopants is one possible strategy.To verify this,in numerous doping configurations of N/VO-codoped anatase TiO_(2),we identified two types of VOposition independent N-dopant spatial orderings by efficient screening enabled with a newly designed structural descriptor.Compared with others,these two types of the N-dopant spatial orderings are highly beneficial for charge compensation to produce an apparent overlap between N-2p and O-2p states,therefore achieving a large bandgap narrowing.Furthermore,the two types of the N-dopant spatial orderings can also be generalized to N/VO-codoped rutile TiO_(2)for bandgap narrowing.展开更多
A new layered Cu-based oxychalcogenide Ba_3Fe_2O_5Cu_2S_2 has been synthesized and its magnetic and electronic properties were revealed. Ba_3Fe_2O_5Cu_2S_2 is built up by alternatively stacking [Cu_2S_2]^（2-） layers...A new layered Cu-based oxychalcogenide Ba_3Fe_2O_5Cu_2S_2 has been synthesized and its magnetic and electronic properties were revealed. Ba_3Fe_2O_5Cu_2S_2 is built up by alternatively stacking [Cu_2S_2]^（2-） layers and iron perovskite oxide[（FeO_2）（BaO）（FeO_2）]^（2-）layers along the c axis that are separated by barium ions with Fe^（3＋） fivefold coordinated by a square-pyramidal arrangement of oxygen. From the bond valence arguments, we inferred that in layered CuC h-based（Ch =S, Se, Te） compounds the ＋3 cation in perovskite oxide sheet prefers a square pyramidal site, while the lower valence cation prefers the square planar sites. The studies on susceptibility, transport, and optical reflectivity indicate that Ba_3Fe_2O_5Cu_2S_2 is an antiferromagnetic semiconductor with a Ne′el temperature of 121 K and an optical bandgap of 1.03 eV. The measurement of heat capacity from 10 K to room temperature shows no anomaly at 121 K. The Debye temperature is determined to be 113 K. Theoretical calculations indicate that the conduction band minimum is predominantly contributed by O 2p and 3 d states of Fe ions that antiferromagnetically arranged in FeO_2 layers. The Fe 3d states are located at lower energy and result in a narrow bandgap in comparison with that of the isostructural Sr_3Sc_2O_5Cu_2S_2.展开更多
The development of single-component photocatalysts with narrow bandgaps(2.0-3.0 eV)has been one of the most important goals for photocatalytic H_(2)production,for which I-III-VI multinary sulfides play an important ro...The development of single-component photocatalysts with narrow bandgaps(2.0-3.0 eV)has been one of the most important goals for photocatalytic H_(2)production,for which I-III-VI multinary sulfides play an important role due to their widely tunable composition-dependent bandgap.However,simultaneous bandgap narrowing and photocatalytic activity enhancement in the I-III-VI sulfides are often difficult to achieve due to increased defect states.Here,a series of Cu-In-Zn-S quantum dots(QDs)were synthesized by a facile hydrothermal method focusing on a more profound understanding of bandgap tuning and the subsequent effect on the photocatalytic process by controlling the Cu content.The bandgap of the QDs can be effectively tuned from 2.90 eV to 1.98 eV with an increasing Cu:In ratio from 0.05:10 to 2.5:10 and a color change from light yellow to dark red.The QDs show photocatalytic H_(2)production activity even without any cocatalyst,but it quickly starts to decrease with the Cu/In ratio over 0.1:10(bandgap of 2.59 eV),which highly limits the potential for visible light photocatalysis.Interestingly,Pt-loading effectively enhanced not only the tolerance of Cu incorporation,but also enabled a high H_(2)production activity even with further bandgap narrowing down to~2 eV.The best photocatalytic performance of 456.4μmol h^(-1)g^(-1)was achieved for the Cu:In:Zn ratio of 1:10:5 with a bandgap of 2.27 eV.This increased tolerance of Cu content may result from a combined effect of charge separation by Pt as the cocatalyst that alleviated the Cu-induced charge recombination.The enhanced charge separation was proved by the photoluminescence quenching of the QDs with the cocatalyst.Electrochemical impedance spectroscopy was further used to study the charge separation properties of this photocatalytic system.This is the first observation of the cocatalyst-enhanced tolerance of Cu resulting from the competition of cocatalyst-induced charge separation and defect-induced charge recombination in multinary sulfides,which provides an interesting view and design guideline for the development of narrow bandgap photocatalysts.展开更多
Heavy doping of the base in HBTs brings about a bandgap narrowing （BGN） effect, which modifies the intrinsic carrier density and disturbs the band offset, and thus leads to the change of the currents. Based on a the...Heavy doping of the base in HBTs brings about a bandgap narrowing （BGN） effect, which modifies the intrinsic carrier density and disturbs the band offset, and thus leads to the change of the currents. Based on a thermionic-field-diffusion model that is used to the analyze the performance of an abrupt HBT with a heavydoped base, the conclusion is made that, although the BGN effect makes the currents obviously change due to the modification of the intrinsic carrier density, the band offsets disturbed by the BGN effect should also be taken into account in the analysis of the electrical characteristics of abrupt HBTs. In addition, the BGN effect changes the bias voltage for the onset of Kirk effects.展开更多
Organic-inorganic hybrid solar cells consisting of organic conjugated materials and inorganic quantum dots(QDs)have been of great interest during the past two decades.However,it is still challenging to select desired ...Organic-inorganic hybrid solar cells consisting of organic conjugated materials and inorganic quantum dots(QDs)have been of great interest during the past two decades.However,it is still challenging to select desired organic functional materials for fabricating hybrid films to maximize their photovoltaic performance.Herein,we report the synthesis of three narrow bandgap non-fullerene conjugated polymers and further demonstrate the importance and impact of polymer crystallinity in tuning the organic-inorganic hybrid interface towards improved photovoltaic performance.In specific,we develop an organic-inorganic hybrid active layer using a newly synthesized polymer with relatively weaker crystallinity and FAPbI_(3)QDs,enabling complementary absorption and favorable interface/morphology for efficient charge separation and transport.The champion PCDOT-T/FAPbI_(3)QD hybrid device achieves a record-high efficiency of 13.11%based on the one-step coating organic/QD hybrid bulk heterojunction blend,which is significantly improved relative to the semi-crystalline polymer PYIT-based hybrid device(11.23%)and pristine QD(10.51%).We believe these findings would provide new insight into the organic/QD interface to construct desired hybrid films for high-performing optoelectronic applications.展开更多
Construction of electron donor-acceptor(D-A)conjugated system is an established strategy for achieving reverse saturable absorption(RSA)and broadband optical limiting(OL).Nevertheless,organic materials exhibit OL abil...Construction of electron donor-acceptor(D-A)conjugated system is an established strategy for achieving reverse saturable absorption(RSA)and broadband optical limiting(OL).Nevertheless,organic materials exhibit OL ability across the visible to near-infrared-II spectra range remain scarce.Herein,a series of D-A typeπ-conjugated copolymers with ultra-narrow bandgaps(0.62-0.76 e V)and strong ICT absorption were synthesized by coupling electron-withdrawing block[1,2,5]thiadiazolo[3,4-g]quinoxaline(TQ)with various electron-donating groups(thiophene,selenophene,bithiophene,di(thiophen-2-yl)ethene,and thienothiophene for P1-P5,respectively).Z-scan experiments reveal that all copolymers exhibit RSA behaviours at both 532 and 1064 nm,while P1,P3 and P4 maintain RSA performance extending to 1600 nm.Among all copolymers,P5 exhibits the strongest RSA performance upon both 532 and 1064 nm laser pulses,with the highest nonlinear absorption coefficient(β_(eff))of 51.5 and 49.4 cm·GW^(-1),respectively,and the lowest OL onset fluence(Fon)of 0.31 and 0.38 J·cm^(-2),respectively.In contrast,P4 shows optimal RSA property at 1600 nm laser pulse,withβeff of 13.1 cm·GW^(-1)and Fon of 1.43 J·cm^(-2),respectively.Combining the results of Z-scan and UV-Vis-NIR experiments,it can be speculated that moderate ground-state absorption,rather than excessively strong absorption,favors superior RSA properties.This work offers valuable insights for designing copolymers with excellent RSA behavior,as well as presents a class of candidate material systems for ultrabroadband optical limiting.展开更多
Photocatalytic water splitting, which directly converts solar energy into hydrogen, is one of the most desirable solar-energy-conversion approaches. The ultimate target of photocatalysis is to explore efficient and st...Photocatalytic water splitting, which directly converts solar energy into hydrogen, is one of the most desirable solar-energy-conversion approaches. The ultimate target of photocatalysis is to explore efficient and stable photocatalysts for solar water splitting. Tantalum （oxy）nitride-based materials are a class of the most promising photocatalysts for solar water splitting because of their narrow bandgaps and sufficient band energy potentials for water splitting. Tantalum （oxy）nitride-based photocatalysts have experienced intensive exploration, and encouraging progress has been achieved over the past years. However, the solar- to-hydrogen （STH） conversion efficiency is still very far from its theoretical value. The question of how to better design these materials in order to further improve their water-splitting capability is of interest and importance. This review summarizes the development of tantalum （oxy）nitride-based photocatalysts for solar water spitting. Special interest is paid to important strategies for improving photocatalytic water- splitting efficiency. This paper also proposes future trends to explore in the research area of tantalum-based narrow bandgap photocatalysts for solar water splitting.展开更多
Integrating electrocatalytic and photocatalytic functionalities into a single-component system offers a promising strategy for enhancing catalytic activity in photo-assisted electrocatalysis.This synergy is critical f...Integrating electrocatalytic and photocatalytic functionalities into a single-component system offers a promising strategy for enhancing catalytic activity in photo-assisted electrocatalysis.This synergy is critical for advancing energy conversion efficiency,yet significant challenges persist,particularly in optimizing individual layers and minimizing charge recombination.In this work,we present a novel singlecomponent photo-assisted electrocatalytic system based on Ni-or Co-doped CeO_(2),which simultaneously functions as a light absorber and electrocatalyst.We elucidate the critical relationship between bandgap engineering and d-band states,demonstrating that controlled modulation of dopant-derived 3d states within the CeO_(2)bandgap facilitates visible-light harvesting and optimizes the adsorption energetics of key reaction intermediates.Specifically,Ni-doped CeO_(2)introduces additional 3d states near the Fermi level,narrowing the bandgap from 3.0 to 2.7 eV.This modification not only enhances visible-light absorption but also improves charge transfer efficiency at the catalyst-electrolyte interface.Density functional theory(DFT)calculations and spectroscopic analyses reveal that Ni doping significantly enhances performance,achieving a 64 mV reduction in overpotential at 50 mA/cm^(2)under illumination,while Co-doped CeO_(2)exhibits a 35 mV reduction in 1 M NaOH.Our findings demonstrate that a simple doping strategy can tailor 3d states to promote efficient charge carrier separation and intermediate transfer,offering a versatile and scalable approach to designing advanced electrocatalysts for water splitting.展开更多
Piezoelectric transduction technology enables the direct conversion between mechanical and electrical energy,finding extensive applications in sensing,acoustics,imaging,actuation,and energy harvesting[1].Previous stud...Piezoelectric transduction technology enables the direct conversion between mechanical and electrical energy,finding extensive applications in sensing,acoustics,imaging,actuation,and energy harvesting[1].Previous studies on piezoelectric materials have primarily focused on ceramics or single-crystal materials characterized by wide band gaps(E_(g)>2.0 e V[2])and low electrical conductivity.In contrast,narrow-bandgap(E_(g)<0.5 eV[3])semiconductor materials typically exhibit high electrical conductivity,which is unfavorable for the effective accumulation of charges required to establish a stable voltage response.Consequently,experimental investigations into the piezoelectric effect of narrow-bandgap semiconductors are scarce.展开更多
To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reporte...To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reported.The doping effect and the application of graphene as cocatalyst for CdS is studied for photocatalytic H_(2) generation.The most active sample consists of CdS and graphene(CdS-0.15G)exhibits promising photocatalytic activity,producing 3.12 mmol g^-(1) h^-(1) of H_(2) under simulated solar light which is^4.6 times superior than pure CdS nanoparticles giving an apparent quantum efficiency(AQY)of 11.7%.The enhanced photocatalytic activity for H_(2) generation is associated to the narrowing of the bandgap,enhanced light absorption,fast interfacial charge transfer,and higher carrier density(N_(D))in C-doped CdS@G samples.This is achieved by C doping in CdS nanoparticles and the formation of a graphene shell over the C-doped CdS nanoparticles.After stability test,the spent catalysts sample was also characterized to investigate the nanostructure.展开更多
Narrow bandgap ferroelectrics are emerging as critical components for assembling high-performance optoelectronic devices with a broadband spectral response,yet integrating narrow bandgap and robust ferroelectricity in...Narrow bandgap ferroelectrics are emerging as critical components for assembling high-performance optoelectronic devices with a broadband spectral response,yet integrating narrow bandgap and robust ferroelectricity in a single-phase material system remains a huge challenge.Herein,we report a narrow bandgap improper molecular ferroelectric,(DMAPA)BiI5(1;DMAPA=dimethylaminopropyl ammonium),which has a bandgap of 1.94 eV and a spontaneous polarization(Ps)value of 1.38μC cm^(−2).It is notable that 1 exhibits unusual dielectric bistability near its Curie temperature(Tc)=372 K,along with only quite small variation in dielectric constants.This characteristic of improper ferroelectricity endows 1 with large pyroelectric figures-of-merit.Strikingly,light-induced change of its electric Ps leads to ultraviolet-to-near-infrared pyroelectricity in a wide spectral region(266–980 nm),thus achieving broadband self-powered photoactivities.High-quality thin films of 1 fabricated via a spin-coating process also exhibit excellent light-induced pyroelectric effects.The integration of photoactivities in narrow bandgap improper ferroelectrics offers a promising pathway toward scalable broadband optoelectronic device application.展开更多
A novel 2D bilayered Dion–Jacobson(DJ)type hybrid perovskite,(2-methyl-1,5-diaminopentane)(methylammonium)Pb2I7(1),with a narrow band gap of 1.96 eV has been reported,and such a DJ-type hybrid has been for the first ...A novel 2D bilayered Dion–Jacobson(DJ)type hybrid perovskite,(2-methyl-1,5-diaminopentane)(methylammonium)Pb2I7(1),with a narrow band gap of 1.96 eV has been reported,and such a DJ-type hybrid has been for the first time demonstrated to exhibit broadband photoresponsive properties with high photoresponsivity(13 A W^(−1)under a 10 V bias)and considerable switching ratios(>10^(3)).展开更多
Narrowing the bandgap and promoting the quality of inorganic perovskites are the key points to improve the performance of inorganic perovskite solar cells.Herein,we incorporate Sn^(2+)into an inorganic CsPbBr_(3)perov...Narrowing the bandgap and promoting the quality of inorganic perovskites are the key points to improve the performance of inorganic perovskite solar cells.Herein,we incorporate Sn^(2+)into an inorganic CsPbBr_(3)perovskite to simultaneously tune the bandgap and improve the quality of the perovskite film.The density functional theory calculations demonstrate that the incorporation of Sn^(2+)leads to an obvious shift of the conduction band minimum of the CsPbBr_(3)perovskite towards the lower energy region.展开更多
Inorganic gold halide perovskites,owing to their excellent stability and tunable bandgaps,are poised to serve as environmentally benign alternatives to lead halide perovskites in the field of photovoltaics.In this stu...Inorganic gold halide perovskites,owing to their excellent stability and tunable bandgaps,are poised to serve as environmentally benign alternatives to lead halide perovskites in the field of photovoltaics.In this study,we successfully synthesized two inorganic auric–aurous halide perovskites,Rb_(2)Au_(2)I_(6)and RbAuCl_(4),using a straightforward and efficient hydrothermal method,achieving millimeter-sized single crystals.Single-crystal structural analysis revealed that Rb_(2)Au_(2)I_(6)exhibits a three-dimensional(3D)double perovskite structure,whereas RbAuCl_(4)shows a two-dimensional(2D)Dion–Jacobson(DJ)-type perovskite structure.We further analyzed their crystallographic information and elucidated the reasons behind the structural differences between them.Moreover,first-principles calculations ascertained their high optical absorption coefficients within the visible light spectrum and indirect bandgap properties.Utilizing theoretical models,we discovered that Rb_(2)Au_(2)I_(6)and RbAuCl_(4)exhibit spectroscopic limited maximum efficiency(SLME)of 30.12%and 22.30%,respectively,in films of 500 nm thickness,signifying their potential candidacy as solar cell absorbers.Theoretical calculations related to thermoelectric properties illustrate high ZT(thermoelectric figure of merit)values of about 1.4 and 1.2 at 500 K for Rb_(2)Au_(2)I_(6)and RbAuCl_(4),respectively.Based on the significantly shortened synthesis of Rb_(2)Au_(2)I_(6)and RbAuCl_(4),our study demonstrated their potential in the field of optoelectronics and thermoelectric materials,which could lay a solid foundation for future applications in energy-conversion devices.展开更多
Improving the performance and reducing the manufacturing costs are the main directions for the development of organic solar cells in the future.Here,the strategy that uses chemical structure modification to optimize t...Improving the performance and reducing the manufacturing costs are the main directions for the development of organic solar cells in the future.Here,the strategy that uses chemical structure modification to optimize the photoelectric properties is reported.A new narrow bandgap(1.30 eV)chlorinated non-fullerene electron acceptor(Y15),based on benzo[d][1,2,3] triazole with two 3-undecylthieno[2’,3’:4,5] thieno[3,2-b] pyrrole fused-7-heterocyclic ring,with absorption edge extending to the near-infrared(NIR) region,namely A-DA’D-A type structure,is designed and synthesized.Its electrochemical and optoelectronic properties are systematically investigated.Benefitting from its NIR light harvesting,the fabricated photovoltaic devices based on Y15 deliver a high power conversion efficiency(PCE) of 14.13%,when blending with a wide bandgap polymer donor PM6.Our results show that the A-DA’D-A type molecular design and application of near-infrared electron acceptors have the potential to further improve the PCE of polymer solar cells(PSCs).展开更多
Two acceptor-donor-acceptor(A-D-A)type non-fullerene acceptors(namely WH1 and WH7)containing the oxindole-based bridge are designed and synthesized for polymer solar cells(PSCs)applications.The bridge unit is introduc...Two acceptor-donor-acceptor(A-D-A)type non-fullerene acceptors(namely WH1 and WH7)containing the oxindole-based bridge are designed and synthesized for polymer solar cells(PSCs)applications.The bridge unit is introduced through a precursor(6-bromo-1-octylindoline-2,3-dione)that contains both bromine and carbonyl and provides the feasibility of the Pd-catalyzed cross-coupling reaction and the Knoevenagel condensation,respectively.This facile synthetic approach exhibits the potential to gain high performance non-fullerene acceptors through extendingπ-conjugated backbone with strong light-absorbing building blocks.The synthesis and properties of WH1 and WH7 are demonstrated with different endcap units,then PSCs are fabricated using PBDB-T:WH1 and PBDB-T:WH7 as the active layers,and attain an average power conversion efficiency(PCE)of 2.58%and 6.24%,respectively.Further device physics studies afford the deep insight of structure variation influence on the device performance.This work provides a facile non-fullerene acceptor design strategy and shows how structure variations impact the PSC performance.展开更多
Achieving highly-efficient and stable perovskite solar cells(PSCs) with a simplified structure remains challenging, despite the tremendous potential for reducing preparation cost and facile processability by removing ...Achieving highly-efficient and stable perovskite solar cells(PSCs) with a simplified structure remains challenging, despite the tremendous potential for reducing preparation cost and facile processability by removing hole transport layer(HTL). In this work, eco-friendly glucose(Gl) as an interface modifier for HTL-free narrow bandgap tin-lead(Sn-Pb) PSCs is proposed. Gl not only enhances the wettability of the indium tin oxide to promote perovskite heterogeneous nucleation on substrate, but also realizes defect passivation by interacting with uncoordinated Pb^(2+) and Sn^(2+) in perovskite films. As a result, the quality of the perovskite films has been significantly improved, accompanied by reduced defects of bottom interface and optimized energy level structure of device, leading to an efficiency increase and a less nonradiative voltage loss of 0.102 V(for a bandgap of ~1.26 eV). Consequently, the optimized PSC delivers an unprecedented efficiency over 21% with high open-circuit voltage and enhanced stability, outperforming the control device. This work demonstrates a cost-effective approach to develop simplified structure high efficiency HTL-free Sn-Pb PSC.展开更多
There have been huge achievements of all-perovskite tandem solar cells,which recently realized the highest power conversion efficiency of 24.8%.However,the complex device structure and complicated manufacture processe...There have been huge achievements of all-perovskite tandem solar cells,which recently realized the highest power conversion efficiency of 24.8%.However,the complex device structure and complicated manufacture processes severely restrict the further development of all-perovskite tandem solar cells.In this work,we successfully fabricated high-efficiency hole transport material-free(HTM-free)Sn−Pb alloyed narrow bandgap perovskite solar cells(PSCs)by introducing guanidinium thiocyanate(GASCN)and hydroiodic acid(HI)into the perovskite precursor solution.GASCN and HI play a positive synergy effect during perovskite crystallization process resulting in larger grain size,fewer surface defects,and lower trap density to suppress the Sn^(2+)oxidation degradation.Furthermore,they could effectively adjust the energy level of perovskite materials,reduce the energy level difference between perovskite and ITO resulting in more efficiently transport of free hole charge carriers.As a result,with adding GASCN and HI,the achieved highest power conversion efficiency of HTM-free devices increased from 12.58%to 17.85%,which is one of the highest PCEs among all values reported to date for the HTM-free narrow-bandgap(1.2-1.4 eV)Sn−Pb binary PSCs.Moreover,the optimized device shows improved environmental stability.Our additive strategy manifests a remarkable step towards the facile,cost-efficient fabrication of HTM-free perovskite-based tandem solar cells with both high efficiency and simple fabrication process.展开更多
All-fused-ringπ-conjugated molecules have received considerable attention because of their unique electronic structures,low conformation disorder,and excellent optoelectronic properties.Most all-fused-ring molecules ...All-fused-ringπ-conjugated molecules have received considerable attention because of their unique electronic structures,low conformation disorder,and excellent optoelectronic properties.Most all-fused-ring molecules are p-type organic semiconductors and possess medium bandgaps.In this work,we design and synthesize an all-fused-ring molecule(FM1)with an n-type property and narrow bandgap,which is a 10-fused-ring system composed of one electrondeficient benzotriazole core,two electron-rich thienopyrrole bridging units,and two electron-deficient malononitrile-functionalized end-cappers.FM1 exhibits low-lying highest occupied molecular orbit/lowest unoccupied molecular orbit energy levels of−5.77 eV/−3.89 eV,high electron mobility of 6.0×10^(−4)cm^(2)V^(−1)s^(−1),an optical bandgap of 1.50 eV,and a maximum absorption wavelength of 769nm.Because of the all-fused-ring skeleton,FM1 shows superior photostability and chemical stability.We use FM1 as an electron acceptor and successfully construct organic solar cell(OSC)devices with a decent power conversion efficiency(PCE)of 10.8%.Most importantly,the intrinsic stability of FM1 leads to its excellent OSC device stability.After irradiation with simulated solar light for 16 h,while control of the OSC device of the state-of-the-art small molecule electron acceptor shows a 46%decrease of PCE,the FM1’s unencapsulated OSC device exhibits only a 9%decrease of PCE.展开更多
The exploration of efficient lead-free perovskite photoelectric active materials to develop high-performance photoelectrochemical(PEC)systems in aqueous solution is crucial to expand their PEC applications.Herein,we s...The exploration of efficient lead-free perovskite photoelectric active materials to develop high-performance photoelectrochemical(PEC)systems in aqueous solution is crucial to expand their PEC applications.Herein,we successfully constructed a high-performance PEC platform using ligand-free perovskite Cs2PdBr6 microcrystals(MCs)as the photoactive substance.The Cs2PdBr6 MCs showed narrow bandgap,wide absorption range,high electronic mobility and good stability in aqueous solutions.Particularly,the Cs2PdBr6 MCs exhibited an excellent photoresponse,the photocurrent density could reach as high as 98μA/cm^(2)under 10.18 mW/cm^(2)light irradiation in the absence of other electron acceptors.In addition of the extremely wide range of response wavelength,wide pH range and accelerated interfacial carrier transfer,the Cs2PdBr6 MCs demonstrated the significant potential of photocathode active material for applications in PEC sensors and optoelectronic devices.Therefore,this work indicates that Cs2PdBr6 MCs design is a highly efficient way to solve the intrinsic issues of perovskite material,predicting a promising strategy for high performance PEC application in aqueous ambience.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51972312,51825204,21633009)。
文摘Nitrogen(N)doping has been widely adopted to improve the light absorption of TiO_(2).However,the newly introduced N-2p states are largely localized thus barely overlap with O-2p states in the valence band of TiO_(2),resulting in a shoulder-like absorption edge.To realize an apparent overlap between N-2p and O-2p states,charge compensation between N^(3-)and O^(2-)via electron transfer from oxygen vacancies(VO)to N dopants is one possible strategy.To verify this,in numerous doping configurations of N/VO-codoped anatase TiO_(2),we identified two types of VOposition independent N-dopant spatial orderings by efficient screening enabled with a newly designed structural descriptor.Compared with others,these two types of the N-dopant spatial orderings are highly beneficial for charge compensation to produce an apparent overlap between N-2p and O-2p states,therefore achieving a large bandgap narrowing.Furthermore,the two types of the N-dopant spatial orderings can also be generalized to N/VO-codoped rutile TiO_(2)for bandgap narrowing.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51472266,51202286,and 91422303)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07020100)the ICDD
文摘A new layered Cu-based oxychalcogenide Ba_3Fe_2O_5Cu_2S_2 has been synthesized and its magnetic and electronic properties were revealed. Ba_3Fe_2O_5Cu_2S_2 is built up by alternatively stacking [Cu_2S_2]^（2-） layers and iron perovskite oxide[（FeO_2）（BaO）（FeO_2）]^（2-）layers along the c axis that are separated by barium ions with Fe^（3＋） fivefold coordinated by a square-pyramidal arrangement of oxygen. From the bond valence arguments, we inferred that in layered CuC h-based（Ch =S, Se, Te） compounds the ＋3 cation in perovskite oxide sheet prefers a square pyramidal site, while the lower valence cation prefers the square planar sites. The studies on susceptibility, transport, and optical reflectivity indicate that Ba_3Fe_2O_5Cu_2S_2 is an antiferromagnetic semiconductor with a Ne′el temperature of 121 K and an optical bandgap of 1.03 eV. The measurement of heat capacity from 10 K to room temperature shows no anomaly at 121 K. The Debye temperature is determined to be 113 K. Theoretical calculations indicate that the conduction band minimum is predominantly contributed by O 2p and 3 d states of Fe ions that antiferromagnetically arranged in FeO_2 layers. The Fe 3d states are located at lower energy and result in a narrow bandgap in comparison with that of the isostructural Sr_3Sc_2O_5Cu_2S_2.
基金support from the National Natural Science Foundation of China(21501072 and 21522603)the Jiangsu Specially-Appointed Professors Program,the Chinese-German Cooperation Research Project(GZ1091)+3 种基金the Natural Science Foundation of Jiangsu Province(BK20150489)the“Innovative and Entrepreneurial Doctor”Program of Jiangsu Province,the China Postdoctoral Science Foundation(2016M590419)the Jiangsu Province Postdoctoral Foundation(1501027A)the Start Funding of Jiangsu University(15JDG011 and 15JDG027).
文摘The development of single-component photocatalysts with narrow bandgaps(2.0-3.0 eV)has been one of the most important goals for photocatalytic H_(2)production,for which I-III-VI multinary sulfides play an important role due to their widely tunable composition-dependent bandgap.However,simultaneous bandgap narrowing and photocatalytic activity enhancement in the I-III-VI sulfides are often difficult to achieve due to increased defect states.Here,a series of Cu-In-Zn-S quantum dots(QDs)were synthesized by a facile hydrothermal method focusing on a more profound understanding of bandgap tuning and the subsequent effect on the photocatalytic process by controlling the Cu content.The bandgap of the QDs can be effectively tuned from 2.90 eV to 1.98 eV with an increasing Cu:In ratio from 0.05:10 to 2.5:10 and a color change from light yellow to dark red.The QDs show photocatalytic H_(2)production activity even without any cocatalyst,but it quickly starts to decrease with the Cu/In ratio over 0.1:10(bandgap of 2.59 eV),which highly limits the potential for visible light photocatalysis.Interestingly,Pt-loading effectively enhanced not only the tolerance of Cu incorporation,but also enabled a high H_(2)production activity even with further bandgap narrowing down to~2 eV.The best photocatalytic performance of 456.4μmol h^(-1)g^(-1)was achieved for the Cu:In:Zn ratio of 1:10:5 with a bandgap of 2.27 eV.This increased tolerance of Cu content may result from a combined effect of charge separation by Pt as the cocatalyst that alleviated the Cu-induced charge recombination.The enhanced charge separation was proved by the photoluminescence quenching of the QDs with the cocatalyst.Electrochemical impedance spectroscopy was further used to study the charge separation properties of this photocatalytic system.This is the first observation of the cocatalyst-enhanced tolerance of Cu resulting from the competition of cocatalyst-induced charge separation and defect-induced charge recombination in multinary sulfides,which provides an interesting view and design guideline for the development of narrow bandgap photocatalysts.
基金supported by the State Key Development Program for Basic Research of China (No. 2003CB314901)
文摘Heavy doping of the base in HBTs brings about a bandgap narrowing （BGN） effect, which modifies the intrinsic carrier density and disturbs the band offset, and thus leads to the change of the currents. Based on a thermionic-field-diffusion model that is used to the analyze the performance of an abrupt HBT with a heavydoped base, the conclusion is made that, although the BGN effect makes the currents obviously change due to the modification of the intrinsic carrier density, the band offsets disturbed by the BGN effect should also be taken into account in the analysis of the electrical characteristics of abrupt HBTs. In addition, the BGN effect changes the bias voltage for the onset of Kirk effects.
基金financially supported by the National Key Research and Development Program of China(2022YFE0110300)the National Natural Science Foundation of China(52261145696 and 52473187)+1 种基金the“111”Projectthe Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University。
文摘Organic-inorganic hybrid solar cells consisting of organic conjugated materials and inorganic quantum dots(QDs)have been of great interest during the past two decades.However,it is still challenging to select desired organic functional materials for fabricating hybrid films to maximize their photovoltaic performance.Herein,we report the synthesis of three narrow bandgap non-fullerene conjugated polymers and further demonstrate the importance and impact of polymer crystallinity in tuning the organic-inorganic hybrid interface towards improved photovoltaic performance.In specific,we develop an organic-inorganic hybrid active layer using a newly synthesized polymer with relatively weaker crystallinity and FAPbI_(3)QDs,enabling complementary absorption and favorable interface/morphology for efficient charge separation and transport.The champion PCDOT-T/FAPbI_(3)QD hybrid device achieves a record-high efficiency of 13.11%based on the one-step coating organic/QD hybrid bulk heterojunction blend,which is significantly improved relative to the semi-crystalline polymer PYIT-based hybrid device(11.23%)and pristine QD(10.51%).We believe these findings would provide new insight into the organic/QD interface to construct desired hybrid films for high-performing optoelectronic applications.
基金supported by the National Natural Science Foundation of China(No.52102013)。
文摘Construction of electron donor-acceptor(D-A)conjugated system is an established strategy for achieving reverse saturable absorption(RSA)and broadband optical limiting(OL).Nevertheless,organic materials exhibit OL ability across the visible to near-infrared-II spectra range remain scarce.Herein,a series of D-A typeπ-conjugated copolymers with ultra-narrow bandgaps(0.62-0.76 e V)and strong ICT absorption were synthesized by coupling electron-withdrawing block[1,2,5]thiadiazolo[3,4-g]quinoxaline(TQ)with various electron-donating groups(thiophene,selenophene,bithiophene,di(thiophen-2-yl)ethene,and thienothiophene for P1-P5,respectively).Z-scan experiments reveal that all copolymers exhibit RSA behaviours at both 532 and 1064 nm,while P1,P3 and P4 maintain RSA performance extending to 1600 nm.Among all copolymers,P5 exhibits the strongest RSA performance upon both 532 and 1064 nm laser pulses,with the highest nonlinear absorption coefficient(β_(eff))of 51.5 and 49.4 cm·GW^(-1),respectively,and the lowest OL onset fluence(Fon)of 0.31 and 0.38 J·cm^(-2),respectively.In contrast,P4 shows optimal RSA property at 1600 nm laser pulse,withβeff of 13.1 cm·GW^(-1)and Fon of 1.43 J·cm^(-2),respectively.Combining the results of Z-scan and UV-Vis-NIR experiments,it can be speculated that moderate ground-state absorption,rather than excessively strong absorption,favors superior RSA properties.This work offers valuable insights for designing copolymers with excellent RSA behavior,as well as presents a class of candidate material systems for ultrabroadband optical limiting.
基金The authors would like to acknowledge financial support from the Australian Research Council through its DP and FF programs. Mu Xiao acknowledges support from the Australian Government Research Training Program Scholarship. Financial support from the National Natural Science Foundation of China （513228201） is also highly appreciated.
文摘Photocatalytic water splitting, which directly converts solar energy into hydrogen, is one of the most desirable solar-energy-conversion approaches. The ultimate target of photocatalysis is to explore efficient and stable photocatalysts for solar water splitting. Tantalum （oxy）nitride-based materials are a class of the most promising photocatalysts for solar water splitting because of their narrow bandgaps and sufficient band energy potentials for water splitting. Tantalum （oxy）nitride-based photocatalysts have experienced intensive exploration, and encouraging progress has been achieved over the past years. However, the solar- to-hydrogen （STH） conversion efficiency is still very far from its theoretical value. The question of how to better design these materials in order to further improve their water-splitting capability is of interest and importance. This review summarizes the development of tantalum （oxy）nitride-based photocatalysts for solar water spitting. Special interest is paid to important strategies for improving photocatalytic water- splitting efficiency. This paper also proposes future trends to explore in the research area of tantalum-based narrow bandgap photocatalysts for solar water splitting.
基金the support of the Henry Royce Institute for Advanced Materials through the Industrial Collaboration Programme(RICP-R4-100061)and MATcelerateZero(MATZ0)funded from a grant provided by the Engineering and Physical Sciences Research Council EP/X527257/1+6 种基金the Department for Energy Security and Net Zero(Project ID:NEXTCCUS)University College London’s Research,Innovation and Global Engagement,University of Sydney–University College London Partnership Collaboration AwardsUCL-Peking University Strategic Partner FundsCornell-UCL Global Strategic Collaboration Awards and IISc-UCL Joint seed fund for their financial supportthe ACT program(Accelerating CCS Technologies,Horizon2020 Project No.691712)for the financial support of the NEXTCCUS project(project ID:327327)Cambridge Royce facilities grant EP/P024947/1Sir Henry Royce Institute–recurrent grant EP/R00661X/1。
文摘Integrating electrocatalytic and photocatalytic functionalities into a single-component system offers a promising strategy for enhancing catalytic activity in photo-assisted electrocatalysis.This synergy is critical for advancing energy conversion efficiency,yet significant challenges persist,particularly in optimizing individual layers and minimizing charge recombination.In this work,we present a novel singlecomponent photo-assisted electrocatalytic system based on Ni-or Co-doped CeO_(2),which simultaneously functions as a light absorber and electrocatalyst.We elucidate the critical relationship between bandgap engineering and d-band states,demonstrating that controlled modulation of dopant-derived 3d states within the CeO_(2)bandgap facilitates visible-light harvesting and optimizes the adsorption energetics of key reaction intermediates.Specifically,Ni-doped CeO_(2)introduces additional 3d states near the Fermi level,narrowing the bandgap from 3.0 to 2.7 eV.This modification not only enhances visible-light absorption but also improves charge transfer efficiency at the catalyst-electrolyte interface.Density functional theory(DFT)calculations and spectroscopic analyses reveal that Ni doping significantly enhances performance,achieving a 64 mV reduction in overpotential at 50 mA/cm^(2)under illumination,while Co-doped CeO_(2)exhibits a 35 mV reduction in 1 M NaOH.Our findings demonstrate that a simple doping strategy can tailor 3d states to promote efficient charge carrier separation and intermediate transfer,offering a versatile and scalable approach to designing advanced electrocatalysts for water splitting.
文摘Piezoelectric transduction technology enables the direct conversion between mechanical and electrical energy,finding extensive applications in sensing,acoustics,imaging,actuation,and energy harvesting[1].Previous studies on piezoelectric materials have primarily focused on ceramics or single-crystal materials characterized by wide band gaps(E_(g)>2.0 e V[2])and low electrical conductivity.In contrast,narrow-bandgap(E_(g)<0.5 eV[3])semiconductor materials typically exhibit high electrical conductivity,which is unfavorable for the effective accumulation of charges required to establish a stable voltage response.Consequently,experimental investigations into the piezoelectric effect of narrow-bandgap semiconductors are scarce.
基金support from the Research Council of Norway provided by the Norwegian Center for Transmission Electron Microscopy,NORTEM(197405/F50)NTNU NanoLab(grant number 245963)which have provided the characterization toolsthe strategic funding support provided by Department of Chemical Engineering,NTNU,Trondheim,Norway.
文摘To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reported.The doping effect and the application of graphene as cocatalyst for CdS is studied for photocatalytic H_(2) generation.The most active sample consists of CdS and graphene(CdS-0.15G)exhibits promising photocatalytic activity,producing 3.12 mmol g^-(1) h^-(1) of H_(2) under simulated solar light which is^4.6 times superior than pure CdS nanoparticles giving an apparent quantum efficiency(AQY)of 11.7%.The enhanced photocatalytic activity for H_(2) generation is associated to the narrowing of the bandgap,enhanced light absorption,fast interfacial charge transfer,and higher carrier density(N_(D))in C-doped CdS@G samples.This is achieved by C doping in CdS nanoparticles and the formation of a graphene shell over the C-doped CdS nanoparticles.After stability test,the spent catalysts sample was also characterized to investigate the nanostructure.
基金supported by NSFC(22125110,U23A2094,22205233,22305248 and U21A2069)the Natural Science Foundation of Fujian Province(2023J02028 and 2025J01247)+2 种基金the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR126)the Postdoctoral Fellowship Program of CPSF(GZB20240746)the China Postdoctoral Science Foundation(2024T170923 and 2024M753233).
文摘Narrow bandgap ferroelectrics are emerging as critical components for assembling high-performance optoelectronic devices with a broadband spectral response,yet integrating narrow bandgap and robust ferroelectricity in a single-phase material system remains a huge challenge.Herein,we report a narrow bandgap improper molecular ferroelectric,(DMAPA)BiI5(1;DMAPA=dimethylaminopropyl ammonium),which has a bandgap of 1.94 eV and a spontaneous polarization(Ps)value of 1.38μC cm^(−2).It is notable that 1 exhibits unusual dielectric bistability near its Curie temperature(Tc)=372 K,along with only quite small variation in dielectric constants.This characteristic of improper ferroelectricity endows 1 with large pyroelectric figures-of-merit.Strikingly,light-induced change of its electric Ps leads to ultraviolet-to-near-infrared pyroelectricity in a wide spectral region(266–980 nm),thus achieving broadband self-powered photoactivities.High-quality thin films of 1 fabricated via a spin-coating process also exhibit excellent light-induced pyroelectric effects.The integration of photoactivities in narrow bandgap improper ferroelectrics offers a promising pathway toward scalable broadband optoelectronic device application.
基金supported by the National Natural Science Foundation of China(21871167)National Natural Science Foundation of Shanxi Province(No.201801D221098)1331 Project of Shanxi and Horizontal Project of School Enterprise Cooperation(No.231023901001).
文摘A novel 2D bilayered Dion–Jacobson(DJ)type hybrid perovskite,(2-methyl-1,5-diaminopentane)(methylammonium)Pb2I7(1),with a narrow band gap of 1.96 eV has been reported,and such a DJ-type hybrid has been for the first time demonstrated to exhibit broadband photoresponsive properties with high photoresponsivity(13 A W^(−1)under a 10 V bias)and considerable switching ratios(>10^(3)).
基金supported by the Foundation of Education Department of Liaoning Province(2019LZ003).
文摘Narrowing the bandgap and promoting the quality of inorganic perovskites are the key points to improve the performance of inorganic perovskite solar cells.Herein,we incorporate Sn^(2+)into an inorganic CsPbBr_(3)perovskite to simultaneously tune the bandgap and improve the quality of the perovskite film.The density functional theory calculations demonstrate that the incorporation of Sn^(2+)leads to an obvious shift of the conduction band minimum of the CsPbBr_(3)perovskite towards the lower energy region.
基金the National Natural Science Foundation of China(Grant No.22175180 and 52311530673).
文摘Inorganic gold halide perovskites,owing to their excellent stability and tunable bandgaps,are poised to serve as environmentally benign alternatives to lead halide perovskites in the field of photovoltaics.In this study,we successfully synthesized two inorganic auric–aurous halide perovskites,Rb_(2)Au_(2)I_(6)and RbAuCl_(4),using a straightforward and efficient hydrothermal method,achieving millimeter-sized single crystals.Single-crystal structural analysis revealed that Rb_(2)Au_(2)I_(6)exhibits a three-dimensional(3D)double perovskite structure,whereas RbAuCl_(4)shows a two-dimensional(2D)Dion–Jacobson(DJ)-type perovskite structure.We further analyzed their crystallographic information and elucidated the reasons behind the structural differences between them.Moreover,first-principles calculations ascertained their high optical absorption coefficients within the visible light spectrum and indirect bandgap properties.Utilizing theoretical models,we discovered that Rb_(2)Au_(2)I_(6)and RbAuCl_(4)exhibit spectroscopic limited maximum efficiency(SLME)of 30.12%and 22.30%,respectively,in films of 500 nm thickness,signifying their potential candidacy as solar cell absorbers.Theoretical calculations related to thermoelectric properties illustrate high ZT(thermoelectric figure of merit)values of about 1.4 and 1.2 at 500 K for Rb_(2)Au_(2)I_(6)and RbAuCl_(4),respectively.Based on the significantly shortened synthesis of Rb_(2)Au_(2)I_(6)and RbAuCl_(4),our study demonstrated their potential in the field of optoelectronics and thermoelectric materials,which could lay a solid foundation for future applications in energy-conversion devices.
基金financially supported by the National Natural Science Foundation of China (Nos.51811530096, 21875286)the National Key Research & Development Projects of China (No.2017YFA0206600)Science Fund for Distinguished Young Scholars of Hunan Province (No.2017JJ1029)
文摘Improving the performance and reducing the manufacturing costs are the main directions for the development of organic solar cells in the future.Here,the strategy that uses chemical structure modification to optimize the photoelectric properties is reported.A new narrow bandgap(1.30 eV)chlorinated non-fullerene electron acceptor(Y15),based on benzo[d][1,2,3] triazole with two 3-undecylthieno[2’,3’:4,5] thieno[3,2-b] pyrrole fused-7-heterocyclic ring,with absorption edge extending to the near-infrared(NIR) region,namely A-DA’D-A type structure,is designed and synthesized.Its electrochemical and optoelectronic properties are systematically investigated.Benefitting from its NIR light harvesting,the fabricated photovoltaic devices based on Y15 deliver a high power conversion efficiency(PCE) of 14.13%,when blending with a wide bandgap polymer donor PM6.Our results show that the A-DA’D-A type molecular design and application of near-infrared electron acceptors have the potential to further improve the PCE of polymer solar cells(PSCs).
基金National Natural Science Foundation of China(No.21805032)Natural Science Foundation of Shanghai,China(No.19ZR1401400)Fundamental Research Funds for the Central Universities,China(No.20D128502).
文摘Two acceptor-donor-acceptor(A-D-A)type non-fullerene acceptors(namely WH1 and WH7)containing the oxindole-based bridge are designed and synthesized for polymer solar cells(PSCs)applications.The bridge unit is introduced through a precursor(6-bromo-1-octylindoline-2,3-dione)that contains both bromine and carbonyl and provides the feasibility of the Pd-catalyzed cross-coupling reaction and the Knoevenagel condensation,respectively.This facile synthetic approach exhibits the potential to gain high performance non-fullerene acceptors through extendingπ-conjugated backbone with strong light-absorbing building blocks.The synthesis and properties of WH1 and WH7 are demonstrated with different endcap units,then PSCs are fabricated using PBDB-T:WH1 and PBDB-T:WH7 as the active layers,and attain an average power conversion efficiency(PCE)of 2.58%and 6.24%,respectively.Further device physics studies afford the deep insight of structure variation influence on the device performance.This work provides a facile non-fullerene acceptor design strategy and shows how structure variations impact the PSC performance.
基金supported by the National Natural Science Foundation of China (Grant No. 12074321)the Young Science and Technology Talents Development Project of Guizhou Provincial Education Department (Grant No. QJH-KY [2022]012)+2 种基金the Fundamental Research Funds for the Central Universities (Grant No. SWU020019)the Natural Science Foundation of Chongqing (Grant No. cstc2020jcyjmsxmx0648)the Chongqing Graduate Student Research Innovation Project (Grant No. CYB22119)。
文摘Achieving highly-efficient and stable perovskite solar cells(PSCs) with a simplified structure remains challenging, despite the tremendous potential for reducing preparation cost and facile processability by removing hole transport layer(HTL). In this work, eco-friendly glucose(Gl) as an interface modifier for HTL-free narrow bandgap tin-lead(Sn-Pb) PSCs is proposed. Gl not only enhances the wettability of the indium tin oxide to promote perovskite heterogeneous nucleation on substrate, but also realizes defect passivation by interacting with uncoordinated Pb^(2+) and Sn^(2+) in perovskite films. As a result, the quality of the perovskite films has been significantly improved, accompanied by reduced defects of bottom interface and optimized energy level structure of device, leading to an efficiency increase and a less nonradiative voltage loss of 0.102 V(for a bandgap of ~1.26 eV). Consequently, the optimized PSC delivers an unprecedented efficiency over 21% with high open-circuit voltage and enhanced stability, outperforming the control device. This work demonstrates a cost-effective approach to develop simplified structure high efficiency HTL-free Sn-Pb PSC.
基金financially supported by the Joint Funds Project funding from Guangdong Basic and Applied Basic Research Foundation(Grant No.2019B1515120083)the National Natural Science Foundation of China(Grant No.U19A2089)+4 种基金the Key Fundamental Research Project funding from the Shenzhen Science and Technology Innovation Committee(Grant No.JCYJ20200109141014474)the National Key Research and Development Project from the Ministry of Science and Technology of China(Grants Nos.2016YFA0202400 and 2016YFA0202404)the Peacock Team Project from Shenzhen Science and Technology Innovation Committee(Grant No.KQTD2015033110182370)Shenzhen Engineering R&D Center for Flexible Solar Cells project funding from Shenzhen Development and Reform Committee(Grant No.2019-126)the Guangdong-Hong Kong-Macao Joint Laboratory(Grant No.2019B121205001).
文摘There have been huge achievements of all-perovskite tandem solar cells,which recently realized the highest power conversion efficiency of 24.8%.However,the complex device structure and complicated manufacture processes severely restrict the further development of all-perovskite tandem solar cells.In this work,we successfully fabricated high-efficiency hole transport material-free(HTM-free)Sn−Pb alloyed narrow bandgap perovskite solar cells(PSCs)by introducing guanidinium thiocyanate(GASCN)and hydroiodic acid(HI)into the perovskite precursor solution.GASCN and HI play a positive synergy effect during perovskite crystallization process resulting in larger grain size,fewer surface defects,and lower trap density to suppress the Sn^(2+)oxidation degradation.Furthermore,they could effectively adjust the energy level of perovskite materials,reduce the energy level difference between perovskite and ITO resulting in more efficiently transport of free hole charge carriers.As a result,with adding GASCN and HI,the achieved highest power conversion efficiency of HTM-free devices increased from 12.58%to 17.85%,which is one of the highest PCEs among all values reported to date for the HTM-free narrow-bandgap(1.2-1.4 eV)Sn−Pb binary PSCs.Moreover,the optimized device shows improved environmental stability.Our additive strategy manifests a remarkable step towards the facile,cost-efficient fabrication of HTM-free perovskite-based tandem solar cells with both high efficiency and simple fabrication process.
基金support by the National Key Research and Development Program of China(grant no.2019YFA0705900)funded by MOST and the National Natural Science Foundation of China(grant nos.22135007 and 21875244).
文摘All-fused-ringπ-conjugated molecules have received considerable attention because of their unique electronic structures,low conformation disorder,and excellent optoelectronic properties.Most all-fused-ring molecules are p-type organic semiconductors and possess medium bandgaps.In this work,we design and synthesize an all-fused-ring molecule(FM1)with an n-type property and narrow bandgap,which is a 10-fused-ring system composed of one electrondeficient benzotriazole core,two electron-rich thienopyrrole bridging units,and two electron-deficient malononitrile-functionalized end-cappers.FM1 exhibits low-lying highest occupied molecular orbit/lowest unoccupied molecular orbit energy levels of−5.77 eV/−3.89 eV,high electron mobility of 6.0×10^(−4)cm^(2)V^(−1)s^(−1),an optical bandgap of 1.50 eV,and a maximum absorption wavelength of 769nm.Because of the all-fused-ring skeleton,FM1 shows superior photostability and chemical stability.We use FM1 as an electron acceptor and successfully construct organic solar cell(OSC)devices with a decent power conversion efficiency(PCE)of 10.8%.Most importantly,the intrinsic stability of FM1 leads to its excellent OSC device stability.After irradiation with simulated solar light for 16 h,while control of the OSC device of the state-of-the-art small molecule electron acceptor shows a 46%decrease of PCE,the FM1’s unencapsulated OSC device exhibits only a 9%decrease of PCE.
基金funded by the National Natural Science Foundation of China(22374021)the Joint Funds for the Innovation of Science and Technology of Fujian Province(2021Y9010)+2 种基金Zong Lian Plan Talent Support Project of the Fujian Medical University(XN240006)Program for Fujian Youth Talent Support Project(2019B016)Program for Fujian Top-notch Innovative Personnel(Fujian Commission Talent[2018]No.5).
文摘The exploration of efficient lead-free perovskite photoelectric active materials to develop high-performance photoelectrochemical(PEC)systems in aqueous solution is crucial to expand their PEC applications.Herein,we successfully constructed a high-performance PEC platform using ligand-free perovskite Cs2PdBr6 microcrystals(MCs)as the photoactive substance.The Cs2PdBr6 MCs showed narrow bandgap,wide absorption range,high electronic mobility and good stability in aqueous solutions.Particularly,the Cs2PdBr6 MCs exhibited an excellent photoresponse,the photocurrent density could reach as high as 98μA/cm^(2)under 10.18 mW/cm^(2)light irradiation in the absence of other electron acceptors.In addition of the extremely wide range of response wavelength,wide pH range and accelerated interfacial carrier transfer,the Cs2PdBr6 MCs demonstrated the significant potential of photocathode active material for applications in PEC sensors and optoelectronic devices.Therefore,this work indicates that Cs2PdBr6 MCs design is a highly efficient way to solve the intrinsic issues of perovskite material,predicting a promising strategy for high performance PEC application in aqueous ambience.
