Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgr...Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgroups(morpholinium(BMMB,BMMD and BMMH),piperidinium(BPMH)and piperazinium(BMPMH))have been synthesized and employed for altering the wettability of vermiculite and its derivates(Vts)treated by Li^(+)-saturated heating method.The results of X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TG-DTG),scanning electron microscopy(SEM)and N_(2)adsorption/desorption isotherms indicate that all of the bis-N-heterocyclic quaternary ammonium salts have been successfully inserted into the vermiculite layers,leading to the organic monolayer.The results of capillary rise tests combined with Lipophilic to Hydrophilic Ratio(LHR)values unveil the wettability alteration of the organo-Vts.As the layer charge decreases,the hydrophilicity of the organo-Vts gradually increases,which is probably caused by the decline in binding sites.As the result of the change in spacer length of modifier,the wetting properties of morpholinium-based organo-Vts change in order of BMMD-Vts>BMMH-Vts>BMMB-Vts,and difference in N-heterocyclic headgroups leads to the sequence of wettability:BMPMH-Vts>BPMH-Vts>BMMH-Vts.Layer charge of Vt,spacer length and the type of the N-heterocyclic headgroup of modifier have the synergistic effect on the regulation of the wettability.展开更多
Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of pero...Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of perovskite structures enable researchers to achieve an incredibly remarkable power conversion efficiency.Flexible hybrid perovskite photovoltaics promise emerging applications in a myriad of optoelectronic and wearable/portable device applications owing to their inherent intriguing physicochemical and photophysical properties which enabled researchers to take forward advanced research in this growing field.Flexible perovskite photovoltaics have attracted significant attention owing to their fascinating material properties with combined merits of high efficiency,light-weight,flexibility,semitransparency,compatibility towards roll-to-roll printing,and large-area mass-scale production.Flexible perovskite-based solar cells comprise of 4 key components that include a flexible substrate,semi-transparent bottom contact electrode,perovskite(light absorber layer)and charge transport(electron/hole)layers and top(usually metal)electrode.Among these components,interfacial layers and contact electrodes play a pivotal role in influencing the overall photovoltaic performance.In this comprehensive review article,we focus on the current developments and latest progress achieved in perovskite photovoltaics concerning the charge selective transport layers/electrodes toward the fabrication of highly stable,efficient flexible devices.As a concluding remark,we briefly summarize the highlights of the review article and make recommendations for future outlook and investigation with perspectives on the perovskite-based optoelectronic functional devices that can be potentially utilized in smart wearable and portable devices.展开更多
A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing(active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted...A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing(active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted in a 1.3 m3tank and a 113 m3bunker.The blast parameters,including the quasistatic pressure(ΔpQS),special impulse(I),and peak overpressure(Δpmax),and images of the explosion process were recorded,and the influence of the Al content(30% and 50%) and Al particle size(1,10,and 50 μm) on the energy release of aluminum/rubber composites were investigated.The results revealed that the use of an active layer increased the peak overpressure generated by the primary blast wave,as well as the quasistatic pressure and special impulse related to fuel burning within tens of milliseconds after detonation.When the Al content was increased from 30% to 50%,the increases of ΔpQS and I were not obvious,and Δpmaxeven decreased,possibly because of decreased combustion efficiency and greater absorption of the blast wave energy for layers with 50% Al.Compared with the pure JH-2charge,the charge with 1 μm Al particles produced the highest Δpmax,indicating that better transient blast performance was generated by smaller Al particles.However,the charge with 10 μm Al particles showed the largest ΔpQSand I,suggesting that a stronger destructive effect occurred over a longer duration for charges that contained moderate 10 μm Al.展开更多
A deep trench super-junction LDMOS with double charge compensation layer(DC DT SJ LDMOS)is proposed in this paper.Due to the capacitance effect of the deep trench which is known as silicon-insulator-silicon(SIS)capaci...A deep trench super-junction LDMOS with double charge compensation layer(DC DT SJ LDMOS)is proposed in this paper.Due to the capacitance effect of the deep trench which is known as silicon-insulator-silicon(SIS)capacitance,the charge balance in the super-junction region of the conventional deep trench SJ LDMOS(Con.DT SJ LDMOS)device will be broken,resulting in breakdown voltage(BV)of the device drops.DC DT SJ LDMOS solves the SIS capacitance effect by adding a vertical variable doped charge compensation layer and a triangular charge compensation layer inside the Con.DT SJ LDMOS device.Therefore,the drift region reaches an ideal charge balance state again.The electric field is optimized by double charge compensation and gate field plate so that the breakdown voltage of the proposed device is improved sharply,meanwhile the enlarged on-current region reduces its specific on-resistance.The simulation results show that compared with the Con.DT SJ LD-MOS,the BV of the DC DT SJ LDMOS has been increased from 549.5 to 705.5 V,and the R_(on,sp) decreased to 23.7 mΩ·cm^(2).展开更多
We demonstrate high current efficiency of a blue fluorescent organic light-emitting diode （OLED） by using the charge control layers （CCLs） based on Alq3 . The CCLs that are inserted into the emitting layers （EMLs...We demonstrate high current efficiency of a blue fluorescent organic light-emitting diode （OLED） by using the charge control layers （CCLs） based on Alq3 . The CCLs that are inserted into the emitting layers （EMLs） could impede the hole injection and facilitate the electron transport, which can improve the carrier balance and further expand the exciton generation region. The maximal current efficiency of the optimal device is 5.89 cd/A at 1.81 mA/cm2 , which is about 2.19 times higher than that of the control device （CD） without the CCL, and the maximal luminance is 19.660 cd/m2 at 12V. The device shows a good color stability though the green light emitting material Alq3 is introduced as the CCL in the EML, but it has a poor lifetime due to the formation of cationic Alq3 species.展开更多
All-solid-state lithium batteries(ASSLBs)have advantages of safety and high energy density,and they are expected to become the next generation of energy storage devices.Sulfide-based solid-state electrolytes(SSEs)with...All-solid-state lithium batteries(ASSLBs)have advantages of safety and high energy density,and they are expected to become the next generation of energy storage devices.Sulfide-based solid-state electrolytes(SSEs)with high ionic conduc-tivity and low grain boundary resistance exhibit remarkable practical application.However,the space charge layer(SCL)eff ect and high interfacial resistance caused by a mismatch with the current commercial oxide cathodes restrict the develop-ment of sulfide SSEs and ASSLBs.This review summarizes the research progress on the SCL eff ect of sulfide SSEs and oxide cathodes,including the mechanism and direct evidence from high performance in-situ characterizations,as well as recent progress on the interfacial modification strategies to alleviate the SCL eff ect.This study provides future direction to stabilize the high performance sulfide-based solid electrolyte/oxide cathode interface for state-of-the-art ASSLBs and future all-SSE storage devices.展开更多
Organic bulk heterojunction fullerence(C60) doped 5, 6, 11, 12-tetraphenylnaphthacene(rubrene) as the high quality charge generation layer(CGL) with high transparency and superior charge generating capability for tand...Organic bulk heterojunction fullerence(C60) doped 5, 6, 11, 12-tetraphenylnaphthacene(rubrene) as the high quality charge generation layer(CGL) with high transparency and superior charge generating capability for tandem organic light emitting diodes(OLEDs) is developed. This CGL shows excellent optical transparency about 90%, which can reduce the optical interference effect formed in tandem OLEDs. There is a stable white light emission including 468 nm and 500 nm peaks from the blue emitting layer and 620 nm peak from the red emitting layer in tandem white OLEDs. A high efficiency of about 17.4 cd/A and CIE coordinates of(0.40, 0.35) at 100 cd/m2 and(0.36, 0.34) at 1000 cd/m2 have been demonstrated by employing the developed CGL, respectively.展开更多
The structural features and three-dimensional nature of the charge density wave （CDW） state of the layered chalcogenide 1T-TaSe2-xTex （0≤x≤2.0） are characterized by Cs-corrected transmission electron microscopy ...The structural features and three-dimensional nature of the charge density wave （CDW） state of the layered chalcogenide 1T-TaSe2-xTex （0≤x≤2.0） are characterized by Cs-corrected transmission electron microscopy measurements. Notable changes of both average structure and the CDW state arising from Te substitution for Se are clearly demonstrated in samples with x〉0.3. The commensurate CDW state characterized by the known star-of-David clustering in the 1T-TaSe2 crystal becomes visibly unstable with Te substitution and vanishes when x=0.3. The 1T-TaSe2-xTex （0.3≤x≤1.3） samples generally adopt a remarkable incommensurate CDW state with monoclinic distortion, which could be fundamentally in correlation with the strong qq-dependent electron-phonon coupling-induced period-lattice-distortion as identified in TaTe22. Systematic analysis demonstrates that the occurrence of superconductivity is related to the suppression of the commensurate CDW phase and the presence of discommensuration is an evident structural feature observed in the superconducting samples.展开更多
As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potentia...As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].展开更多
We investigate the effects of （N,N’-diphenyl）-N,N’-bis（1-naphthyl）-1,1’-biphenyl-4,4’-diamine （NPB） buffer layers on charge collection in inverted ZnO/MEH-PPV hybrid devices. The insertion of a 3-nm NPB thin...We investigate the effects of （N,N’-diphenyl）-N,N’-bis（1-naphthyl）-1,1’-biphenyl-4,4’-diamine （NPB） buffer layers on charge collection in inverted ZnO/MEH-PPV hybrid devices. The insertion of a 3-nm NPB thin layer enhances the efficiency of charge collection by improving charge transport and reducing the interface energy barrier, resulting in better device performances. S-shaped light J–V curve appears when the thickness of the NPB layer reaches 25 nm, which is induced by the inefficient charge extraction from MEH-PPV to Ag. Capacitance–voltage measurements are performed to further investigate the influence of the NPB layer on charge collection from both simulations and experiments.展开更多
Grain-boundary（GB） structures are commonly imaged as discrete atomic columns, yet the chemical modifications are gradual and extend into the adjacent lattices, notably the space charge, hence the two-dimensional def...Grain-boundary（GB） structures are commonly imaged as discrete atomic columns, yet the chemical modifications are gradual and extend into the adjacent lattices, notably the space charge, hence the two-dimensional defects may also be treated as continuum changes to extended interfacial structure. This review presents a spatially-resolved analysis by electron energy-loss spectroscopy of the GB chemical structures in a series of SrTiO3 bicrystals and a ceramic, using analytical electron microscopy of the pre-Cs-correction era. It has identified and separated a transient layer at the model Σ5 grain-boundaries（GBs） with characteristic chemical bonding, extending the continuum interfacial approach to redefine the GB chemical structure. This GB layer has evolved under segregation of iron dopant, starting from subtle changes in local bonds until a clear transition into a distinctive GB chemistry with substantially increased titanium concentration confined within the GB layer in 3-unit cells, heavily strained, and with less strontium. Similar segregated GB layer turns into a titania-based amorphous film in SrTiO3 ceramic, hence reaching a more stable chemical structure in equilibrium with the intergranular Ti2O3 glass also. Space charge was not found by acceptor doping in both the strained Σ5 and amorphous GBs in SrTiO3 owing to the native transient nature of the GB layer that facilitates the transitions induced by Fe segregation into novel chemical structures subject to local and global equilibria. These GB transitions may add a new dimension into the structure–property relationship of the electronic materials.展开更多
To improve the performance of tandem organic light-emitting diodes （OLEDs）, we study the novel NaCl as n-type dopant in Bphen：NaCl layer. By analyzing their relevant energy levels and cartier transporting character...To improve the performance of tandem organic light-emitting diodes （OLEDs）, we study the novel NaCl as n-type dopant in Bphen：NaCl layer. By analyzing their relevant energy levels and cartier transporting characteristics, we discuss the mechanisms of the effective charge generation layer （CGL） of Bphen：NaCl （6 wt%）/MoO3. In addition, we use the Bphen：NaC1 （20 wt%） layer as the electron injection layer （ELL） combining the CGL to further improve the performance of tandem device. For this tandem device, the maximal current efficiency of 9.32 cd/A and the maximal power efficiency of 1.93 lm/W are obtained, which are enhanced approximately by 2.1 and 1.1 times compared with those of the single- emissive-unit device respectively. We attribute this improvement to the increase of electron injection ability by introducing of Bphen：NaCl layer. Moreover, the CGL is almost completely transparent in the visible light region, which is also important to achieve an efficient tandem OLEDs.展开更多
We investigated the thickness effect on the photophysics and charge carrier kinetics of graphitic carbon nitride nanoflakes （g-CNN） by using ultraviolet visible diffuse reflectance spectroscopy, atomic force microsc...We investigated the thickness effect on the photophysics and charge carrier kinetics of graphitic carbon nitride nanoflakes （g-CNN） by using ultraviolet visible diffuse reflectance spectroscopy, atomic force microscopy, femtosecond transient absorption spectroscopy, and picosecond time-correlated single photon counting measurement. For the first time, we found that g-CNN displays a layer-dependent indirect bandgap and layer-dependent charge carrier kinetics.展开更多
Equivalent source layer （ESL） imaging is an important kind of high-resolution electro- encephalogram （EEG） imaging. It consists of two categories： equivalent dipole layer （EDL） and equivalent charge layer （ECL...Equivalent source layer （ESL） imaging is an important kind of high-resolution electro- encephalogram （EEG） imaging. It consists of two categories： equivalent dipole layer （EDL） and equivalent charge layer （ECL）. Both of them are assumed to be located on or near the cortical surface and have been proposed as high-resolution imaging modalities or as intermediate steps to estimate the epicortical potential. Here, EDL and ECL based on a realistic head model are presented, both simulations and real data experiment are done to compare these two models. The results show that ECL can provide higher spatial resolution about source location than EDL does.展开更多
The laser-ion acceleration from the ultra-short and ultra-intense laser-matter interactions attracts more and more interest nowadays. When a laser pulse interacts with a target, relativistic electrons are generated in...The laser-ion acceleration from the ultra-short and ultra-intense laser-matter interactions attracts more and more interest nowadays. When a laser pulse interacts with a target, relativistic electrons are generated in a period of few femtoseconds and driven away by the ponderomotive force, then a huge charge-separation field forms. In general cases, the ion acceleration is determined by this charge-separation field and the scale length of the plasma density. A general time-dependent solution is obtained to describe laser-plasma isothermal expansions into a vacuum, which is the fundamental theory of the laser-ion acceleration. It is adequate for non-quasi-neutral plasmas and different types of the scale length of the density gradient. The previous solutions are some special cases of our general solution. It is found that there exist both a compression layer of the ion velocity distribution and a potential well for sorue initial conditions. However, many unaccounted idiographic solutions, which may be used to reveal new mechanisms of ion acceleration, may be deduced from our general solutions.展开更多
The unsatisfactory performance of individual inorganic and organic solid-state electrolytes has driven the development of composite solid electrolytes(CSEs)for solid-state lithium batteries(SSLBs).However,limited Li^(...The unsatisfactory performance of individual inorganic and organic solid-state electrolytes has driven the development of composite solid electrolytes(CSEs)for solid-state lithium batteries(SSLBs).However,limited Li^(+)transport across lithium-poor space charge layers(SCLs)at the filler/polymer matrix and cathode/CSE interfaces hinders ionic conductivity and compromises the electrochemical performance of SSLBs.Herein,we report a Bi_(2)O_(3)-induced lithium-rich SCL that activates interfacial Li^(+)transportation channels between Li_(0.35)La_(0.55)TiO_(3)(LLTO)filler and poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)matrix,enabling efficient Li^(+)diffusion across their interface.This design achieves a remarkable ionic conductivity of 1.63 mS cm^(-1)and a high lithium transference number of 0.80-approximately two-and three-fold improvements compared to its Bi_(2)O_(3)-free counterpart.Additionally,the dielectric properties of Bi_(2)O_(3)generate a built-in electric field,mitigating lithium-poor SCLs and facilitating Li^(+)transport at the cathode/CSE interface.As a result,the Li symmetric cells exhibit stable operation over 1000 h at 0.5 mA cm^(-2),while the full SSLBs using LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)cathode deliver exceptional electrochemical performance,retaining 86.1%capacity after 200 cycles at 0.5 C.The innovation of creating Lirich SCLs to activate the interfacial Li^(+)transportation channels at the interface provides a new avenue to achieve better CSEs and SSLBs.展开更多
The efficiency of perovskite solar cells(PSCs)has progressed rapidly,exceeding 26%for single-junction devices and surpassing 34%in perovskite-silicon tandem configurations,establishing PSCs as a promising alternative ...The efficiency of perovskite solar cells(PSCs)has progressed rapidly,exceeding 26%for single-junction devices and surpassing 34%in perovskite-silicon tandem configurations,establishing PSCs as a promising alternative to traditional photovoltaic technologies.However,their commercialization is constrained by significant stability challenges in outdoor environments.This review critically examines key cell-level issues affecting the long-term performance and reliability of PSCs,focusing on instabilities arising from the intrinsic phases of the perovskite absorber and external stress factors.Mitigation strategies to enhance stability are discussed,alongside recent advancements in charge transport layers,electrodes,and interfaces aimed at reducing environmental degradation and improving energy level alignment for efficient charge extraction.The importance of accelerated aging tests and the establishment of standardized protocols is underscored for accurately predicting device lifetimes and identifying failure mechanisms,thereby ensuring stability under real-world conditions.Furthermore,a comprehensive techno-economic analysis evaluates how advancements in materials and strategic innovations influence efficiency,durability,and cost,which are critical for the commercial adoption of PSCs.This review delineates the essential steps required to transition PSC technology from laboratory-scale research to widespread commercialization within the global photovoltaic industry.展开更多
As an inherent current-driven device,the luminous intensity of a single-unit perovskite light-emitting diode is directly proportional to the current density.However,this relationship can lead to a deterioration in the...As an inherent current-driven device,the luminous intensity of a single-unit perovskite light-emitting diode is directly proportional to the current density.However,this relationship can lead to a deterioration in the operational lifetime of the device at high current densities.In contrast,a tandem device structure,not only requires less current to achieve equivalent brightness compared to a single-unit device but also nearly achieves the combined efficiencies of each light-emitting unit.Herein,we present recommendations and protocols designed to facilitate the fabrication of all-tandem perovskite light-emitting diode,with the aim of benefiting both the research and industrial communities.展开更多
The development of lithium-ion solid electrolyte provides new ideas for solving the safety problems of secondary lithium-ion batteries(LIB) and, at the same time, the improvement of energy density. However, the conseq...The development of lithium-ion solid electrolyte provides new ideas for solving the safety problems of secondary lithium-ion batteries(LIB) and, at the same time, the improvement of energy density. However, the consequent solid-solid interfacial problems have become a typical bottleneck to the performance. It has been considered that the space charge layer(SCL) formed at the interface to balance the sharp electrochemical inherent difference of properties is one of the most important factors that affect the ion transportation along and across the interface. Its existence may hinder ion transportation and increase the interfacial impedance but may also help to provide a new percolation path for lithium ion and so to enhance the ion migration. However the mechanism of SPL formation and its regulation on ion transport is not very clear, so it has raised a lot of attention and interest from LIB researchers. The purpose of this article is to try to gain some knowledge of SCL and, at the same time to browse through the related research in recent years. Hopefully, it may help those interested in solid electrolyte development for all-solidstate lithium-ion batteries(ASSB) in the future.展开更多
Recently,solution-processed quantum dot lightemitting diodes(QLEDs)have emerged as a promising candidate for next-generation lighting and display devices.However,when given a constant voltage or current,the QLEDs need...Recently,solution-processed quantum dot lightemitting diodes(QLEDs)have emerged as a promising candidate for next-generation lighting and display devices.However,when given a constant voltage or current,the QLEDs need a certain working time to reach their maximum brightness.Such positive aging challenge,dramatically reducing the response speed of the device and causing a luminescence delay,is urgent to be investigated and resolved.In the current work,we introduce a charge-storage layer architecture by inserting copper(I)thiocyanate(CuSCN)between the organic holeinjection layer and hole-transport layer.The extracted holes will be released during the next electrical signal stimulation to increase the efficiency of charge transport.As a result,the response speed of the QLEDs is improved by an order of magnitude.In addition,by inserting an inorganic CuSCN layer,the efficiency,lifetime,and environmental stability of red/green/blue full-color QLEDs are enhanced simultaneously.Moreover,this work provides a generic strategy for the fabrication of fast-response and high-efficiency full-color QLEDs without luminescence delay,which plays a critical role in the practical industrialization of QLEDs.展开更多
基金This work is funded by the National Natural Science Foundation of China(Grant No.21776306).
文摘Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgroups(morpholinium(BMMB,BMMD and BMMH),piperidinium(BPMH)and piperazinium(BMPMH))have been synthesized and employed for altering the wettability of vermiculite and its derivates(Vts)treated by Li^(+)-saturated heating method.The results of X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TG-DTG),scanning electron microscopy(SEM)and N_(2)adsorption/desorption isotherms indicate that all of the bis-N-heterocyclic quaternary ammonium salts have been successfully inserted into the vermiculite layers,leading to the organic monolayer.The results of capillary rise tests combined with Lipophilic to Hydrophilic Ratio(LHR)values unveil the wettability alteration of the organo-Vts.As the layer charge decreases,the hydrophilicity of the organo-Vts gradually increases,which is probably caused by the decline in binding sites.As the result of the change in spacer length of modifier,the wetting properties of morpholinium-based organo-Vts change in order of BMMD-Vts>BMMH-Vts>BMMB-Vts,and difference in N-heterocyclic headgroups leads to the sequence of wettability:BMPMH-Vts>BPMH-Vts>BMMH-Vts.Layer charge of Vt,spacer length and the type of the N-heterocyclic headgroup of modifier have the synergistic effect on the regulation of the wettability.
基金the CSIRO Low Emissions Technologies Program for the support of this studythe financial support from the Australian Research Council(ARC)for the Future Fellowship(FT130101337)+4 种基金QUT core funding(QUT/322120-0301/07)supported by NSF MRI(1428992)U.S.-Egypt Science and Technology(S&T)Joint FundSDBoR R&D ProgramEDA University Center Program(ED18DEN3030025)。
文摘Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of perovskite structures enable researchers to achieve an incredibly remarkable power conversion efficiency.Flexible hybrid perovskite photovoltaics promise emerging applications in a myriad of optoelectronic and wearable/portable device applications owing to their inherent intriguing physicochemical and photophysical properties which enabled researchers to take forward advanced research in this growing field.Flexible perovskite photovoltaics have attracted significant attention owing to their fascinating material properties with combined merits of high efficiency,light-weight,flexibility,semitransparency,compatibility towards roll-to-roll printing,and large-area mass-scale production.Flexible perovskite-based solar cells comprise of 4 key components that include a flexible substrate,semi-transparent bottom contact electrode,perovskite(light absorber layer)and charge transport(electron/hole)layers and top(usually metal)electrode.Among these components,interfacial layers and contact electrodes play a pivotal role in influencing the overall photovoltaic performance.In this comprehensive review article,we focus on the current developments and latest progress achieved in perovskite photovoltaics concerning the charge selective transport layers/electrodes toward the fabrication of highly stable,efficient flexible devices.As a concluding remark,we briefly summarize the highlights of the review article and make recommendations for future outlook and investigation with perspectives on the perovskite-based optoelectronic functional devices that can be potentially utilized in smart wearable and portable devices.
基金funded by the National Natural Science Foundation of China(Grant No.11972018)the Defense Pre-Research Joint Foundation of Chinese Ordnance Industry(Grant No.6141B012858)。
文摘A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing(active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted in a 1.3 m3tank and a 113 m3bunker.The blast parameters,including the quasistatic pressure(ΔpQS),special impulse(I),and peak overpressure(Δpmax),and images of the explosion process were recorded,and the influence of the Al content(30% and 50%) and Al particle size(1,10,and 50 μm) on the energy release of aluminum/rubber composites were investigated.The results revealed that the use of an active layer increased the peak overpressure generated by the primary blast wave,as well as the quasistatic pressure and special impulse related to fuel burning within tens of milliseconds after detonation.When the Al content was increased from 30% to 50%,the increases of ΔpQS and I were not obvious,and Δpmaxeven decreased,possibly because of decreased combustion efficiency and greater absorption of the blast wave energy for layers with 50% Al.Compared with the pure JH-2charge,the charge with 1 μm Al particles produced the highest Δpmax,indicating that better transient blast performance was generated by smaller Al particles.However,the charge with 10 μm Al particles showed the largest ΔpQSand I,suggesting that a stronger destructive effect occurred over a longer duration for charges that contained moderate 10 μm Al.
文摘A deep trench super-junction LDMOS with double charge compensation layer(DC DT SJ LDMOS)is proposed in this paper.Due to the capacitance effect of the deep trench which is known as silicon-insulator-silicon(SIS)capacitance,the charge balance in the super-junction region of the conventional deep trench SJ LDMOS(Con.DT SJ LDMOS)device will be broken,resulting in breakdown voltage(BV)of the device drops.DC DT SJ LDMOS solves the SIS capacitance effect by adding a vertical variable doped charge compensation layer and a triangular charge compensation layer inside the Con.DT SJ LDMOS device.Therefore,the drift region reaches an ideal charge balance state again.The electric field is optimized by double charge compensation and gate field plate so that the breakdown voltage of the proposed device is improved sharply,meanwhile the enlarged on-current region reduces its specific on-resistance.The simulation results show that compared with the Con.DT SJ LD-MOS,the BV of the DC DT SJ LDMOS has been increased from 549.5 to 705.5 V,and the R_(on,sp) decreased to 23.7 mΩ·cm^(2).
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60906022 and 60676051)the Natural Science Foundation of Tianjin,China (Grant No. 10JCYBJC01100)+2 种基金the Scientific Developing Foundation of Tianjin Education Commission, China (Grant No. 2011ZD02)the Jiangsu Provincial Natural Science Development Foundation for University, China (Grant No. 09KJB140006)the Tianjin Natural Science Council (Grant No. 10SYSYJC28100)
文摘We demonstrate high current efficiency of a blue fluorescent organic light-emitting diode （OLED） by using the charge control layers （CCLs） based on Alq3 . The CCLs that are inserted into the emitting layers （EMLs） could impede the hole injection and facilitate the electron transport, which can improve the carrier balance and further expand the exciton generation region. The maximal current efficiency of the optimal device is 5.89 cd/A at 1.81 mA/cm2 , which is about 2.19 times higher than that of the control device （CD） without the CCL, and the maximal luminance is 19.660 cd/m2 at 12V. The device shows a good color stability though the green light emitting material Alq3 is introduced as the CCL in the EML, but it has a poor lifetime due to the formation of cationic Alq3 species.
基金financially supported by National Natural Science Foundation of China(Nos.21575015,21203008,21975025,and 51772030)the Beijing Nature Science Foundation(No.2172051),the National Key Research and Develop-ment Program of China(No.2016YFB0100204)+1 种基金Beijing Outstand-ing Young Scientists Program(No.BJJWZYJH01201910007023)funded by State Key Laboratory for Modification of Chemi-cal Fibers and Polymer Materials,Donghua University.
文摘All-solid-state lithium batteries(ASSLBs)have advantages of safety and high energy density,and they are expected to become the next generation of energy storage devices.Sulfide-based solid-state electrolytes(SSEs)with high ionic conduc-tivity and low grain boundary resistance exhibit remarkable practical application.However,the space charge layer(SCL)eff ect and high interfacial resistance caused by a mismatch with the current commercial oxide cathodes restrict the develop-ment of sulfide SSEs and ASSLBs.This review summarizes the research progress on the SCL eff ect of sulfide SSEs and oxide cathodes,including the mechanism and direct evidence from high performance in-situ characterizations,as well as recent progress on the interfacial modification strategies to alleviate the SCL eff ect.This study provides future direction to stabilize the high performance sulfide-based solid electrolyte/oxide cathode interface for state-of-the-art ASSLBs and future all-SSE storage devices.
基金Project supported by the National Natural Science Foundation of China （Grant No. 60906022）, the Natural Science Foundation of Tianjin, China （Grant No. 10JCYBJC01100）, the Scientific Developing Foundation of Tianjin Education Commission, China （Grant No. 2011ZD02）, and the Tianjin Natural Science
文摘Organic bulk heterojunction fullerence(C60) doped 5, 6, 11, 12-tetraphenylnaphthacene(rubrene) as the high quality charge generation layer(CGL) with high transparency and superior charge generating capability for tandem organic light emitting diodes(OLEDs) is developed. This CGL shows excellent optical transparency about 90%, which can reduce the optical interference effect formed in tandem OLEDs. There is a stable white light emission including 468 nm and 500 nm peaks from the blue emitting layer and 620 nm peak from the red emitting layer in tandem white OLEDs. A high efficiency of about 17.4 cd/A and CIE coordinates of(0.40, 0.35) at 100 cd/m2 and(0.36, 0.34) at 1000 cd/m2 have been demonstrated by employing the developed CGL, respectively.
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB921300 and 2012CB821404the National Key Research and Development Program of China under Grant Nos 2016YFA0300300 and 2016YFA0300404+1 种基金the National Natural Science Foundation of China under Grant Nos 11474323,11604372,11274368,91221102,11190022,11674326 and 91422303the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020000
文摘The structural features and three-dimensional nature of the charge density wave （CDW） state of the layered chalcogenide 1T-TaSe2-xTex （0≤x≤2.0） are characterized by Cs-corrected transmission electron microscopy measurements. Notable changes of both average structure and the CDW state arising from Te substitution for Se are clearly demonstrated in samples with x〉0.3. The commensurate CDW state characterized by the known star-of-David clustering in the 1T-TaSe2 crystal becomes visibly unstable with Te substitution and vanishes when x=0.3. The 1T-TaSe2-xTex （0.3≤x≤1.3） samples generally adopt a remarkable incommensurate CDW state with monoclinic distortion, which could be fundamentally in correlation with the strong qq-dependent electron-phonon coupling-induced period-lattice-distortion as identified in TaTe22. Systematic analysis demonstrates that the occurrence of superconductivity is related to the suppression of the commensurate CDW phase and the presence of discommensuration is an evident structural feature observed in the superconducting samples.
基金supported by the National Key R&D Program of China (2018YFE0208500)the Japan Science and Technology Agency (JST) Mirai program (JPMJMI17EA)。
文摘As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].
基金Project supported by the National Basic Research Program of China(Grant No.2010CB327704)the National Natural Science Foundation of China(Grant No.51272022)+2 种基金the Program for New Century Excellent Talents in University of Ministry of Education of China(Grant No.NCET-10-0220)the Research Fund for the Doctoral Program of Higher Education,China(Grant No.20120009130005)the Fundamental Research Funds for the Central Universities,China(Grant No.2012JBZ001)
文摘We investigate the effects of （N,N’-diphenyl）-N,N’-bis（1-naphthyl）-1,1’-biphenyl-4,4’-diamine （NPB） buffer layers on charge collection in inverted ZnO/MEH-PPV hybrid devices. The insertion of a 3-nm NPB thin layer enhances the efficiency of charge collection by improving charge transport and reducing the interface energy barrier, resulting in better device performances. S-shaped light J–V curve appears when the thickness of the NPB layer reaches 25 nm, which is induced by the inefficient charge extraction from MEH-PPV to Ag. Capacitance–voltage measurements are performed to further investigate the influence of the NPB layer on charge collection from both simulations and experiments.
基金supported by the National Natural Science Foundation of China(Grant No.51532006)the Fund from Shanghai Municipal Science and Technology Commission(Grant No.16DZ2260600)+1 种基金the 111 Project of the Ministry of Educationthe Fund from the National Bureau of Foreign Experts(Project No.D16002)
文摘Grain-boundary（GB） structures are commonly imaged as discrete atomic columns, yet the chemical modifications are gradual and extend into the adjacent lattices, notably the space charge, hence the two-dimensional defects may also be treated as continuum changes to extended interfacial structure. This review presents a spatially-resolved analysis by electron energy-loss spectroscopy of the GB chemical structures in a series of SrTiO3 bicrystals and a ceramic, using analytical electron microscopy of the pre-Cs-correction era. It has identified and separated a transient layer at the model Σ5 grain-boundaries（GBs） with characteristic chemical bonding, extending the continuum interfacial approach to redefine the GB chemical structure. This GB layer has evolved under segregation of iron dopant, starting from subtle changes in local bonds until a clear transition into a distinctive GB chemistry with substantially increased titanium concentration confined within the GB layer in 3-unit cells, heavily strained, and with less strontium. Similar segregated GB layer turns into a titania-based amorphous film in SrTiO3 ceramic, hence reaching a more stable chemical structure in equilibrium with the intergranular Ti2O3 glass also. Space charge was not found by acceptor doping in both the strained Σ5 and amorphous GBs in SrTiO3 owing to the native transient nature of the GB layer that facilitates the transitions induced by Fe segregation into novel chemical structures subject to local and global equilibria. These GB transitions may add a new dimension into the structure–property relationship of the electronic materials.
基金Project supported by the National Natural Science Foundation of China(Grant No.60906022)the Natural Science Foundation of Tianjin,China(Grant No.10JCYBJC01100)+1 种基金the Scientific Developing Foundation of Tianjin Education Commission,China(Grant No.2011ZD02)the Key Science and Technology Support Program of Tianjin,China(Grant No.14ZCZDGX00006)
文摘To improve the performance of tandem organic light-emitting diodes （OLEDs）, we study the novel NaCl as n-type dopant in Bphen：NaCl layer. By analyzing their relevant energy levels and cartier transporting characteristics, we discuss the mechanisms of the effective charge generation layer （CGL） of Bphen：NaCl （6 wt%）/MoO3. In addition, we use the Bphen：NaC1 （20 wt%） layer as the electron injection layer （ELL） combining the CGL to further improve the performance of tandem device. For this tandem device, the maximal current efficiency of 9.32 cd/A and the maximal power efficiency of 1.93 lm/W are obtained, which are enhanced approximately by 2.1 and 1.1 times compared with those of the single- emissive-unit device respectively. We attribute this improvement to the increase of electron injection ability by introducing of Bphen：NaCl layer. Moreover, the CGL is almost completely transparent in the visible light region, which is also important to achieve an efficient tandem OLEDs.
基金Financial supports by the National Natural Science Foundation of China (No. 21373269)the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China(No. 10XNJ047)
文摘We investigated the thickness effect on the photophysics and charge carrier kinetics of graphitic carbon nitride nanoflakes （g-CNN） by using ultraviolet visible diffuse reflectance spectroscopy, atomic force microscopy, femtosecond transient absorption spectroscopy, and picosecond time-correlated single photon counting measurement. For the first time, we found that g-CNN displays a layer-dependent indirect bandgap and layer-dependent charge carrier kinetics.
文摘Equivalent source layer （ESL） imaging is an important kind of high-resolution electro- encephalogram （EEG） imaging. It consists of two categories： equivalent dipole layer （EDL） and equivalent charge layer （ECL）. Both of them are assumed to be located on or near the cortical surface and have been proposed as high-resolution imaging modalities or as intermediate steps to estimate the epicortical potential. Here, EDL and ECL based on a realistic head model are presented, both simulations and real data experiment are done to compare these two models. The results show that ECL can provide higher spatial resolution about source location than EDL does.
基金supported by the Key Project of Chinese National Programs for Fundamental Research (973 Program) (No.2006CB806004)National Natural Science Foundation of China (No.10834008)
文摘The laser-ion acceleration from the ultra-short and ultra-intense laser-matter interactions attracts more and more interest nowadays. When a laser pulse interacts with a target, relativistic electrons are generated in a period of few femtoseconds and driven away by the ponderomotive force, then a huge charge-separation field forms. In general cases, the ion acceleration is determined by this charge-separation field and the scale length of the plasma density. A general time-dependent solution is obtained to describe laser-plasma isothermal expansions into a vacuum, which is the fundamental theory of the laser-ion acceleration. It is adequate for non-quasi-neutral plasmas and different types of the scale length of the density gradient. The previous solutions are some special cases of our general solution. It is found that there exist both a compression layer of the ion velocity distribution and a potential well for sorue initial conditions. However, many unaccounted idiographic solutions, which may be used to reveal new mechanisms of ion acceleration, may be deduced from our general solutions.
基金financial support from the National Natural Science Foundation of China(22408239,51904193,22279135)the CAS Strategic Leading Science&Technology Program(B)(XDB1040203)+2 种基金the National Natural Science Foundation of Sichuan(2024NSFSC0987)the Sichuan Province Science and Technology Support Program(2025ZNSFSC0365)the Sichuan University Interdisciplinary Innovation Fund。
文摘The unsatisfactory performance of individual inorganic and organic solid-state electrolytes has driven the development of composite solid electrolytes(CSEs)for solid-state lithium batteries(SSLBs).However,limited Li^(+)transport across lithium-poor space charge layers(SCLs)at the filler/polymer matrix and cathode/CSE interfaces hinders ionic conductivity and compromises the electrochemical performance of SSLBs.Herein,we report a Bi_(2)O_(3)-induced lithium-rich SCL that activates interfacial Li^(+)transportation channels between Li_(0.35)La_(0.55)TiO_(3)(LLTO)filler and poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)matrix,enabling efficient Li^(+)diffusion across their interface.This design achieves a remarkable ionic conductivity of 1.63 mS cm^(-1)and a high lithium transference number of 0.80-approximately two-and three-fold improvements compared to its Bi_(2)O_(3)-free counterpart.Additionally,the dielectric properties of Bi_(2)O_(3)generate a built-in electric field,mitigating lithium-poor SCLs and facilitating Li^(+)transport at the cathode/CSE interface.As a result,the Li symmetric cells exhibit stable operation over 1000 h at 0.5 mA cm^(-2),while the full SSLBs using LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)cathode deliver exceptional electrochemical performance,retaining 86.1%capacity after 200 cycles at 0.5 C.The innovation of creating Lirich SCLs to activate the interfacial Li^(+)transportation channels at the interface provides a new avenue to achieve better CSEs and SSLBs.
基金supported by a National Research Foundation of Korea(NRF)grant(No.2016R1A3B 1908249),funded by the Korean government.
文摘The efficiency of perovskite solar cells(PSCs)has progressed rapidly,exceeding 26%for single-junction devices and surpassing 34%in perovskite-silicon tandem configurations,establishing PSCs as a promising alternative to traditional photovoltaic technologies.However,their commercialization is constrained by significant stability challenges in outdoor environments.This review critically examines key cell-level issues affecting the long-term performance and reliability of PSCs,focusing on instabilities arising from the intrinsic phases of the perovskite absorber and external stress factors.Mitigation strategies to enhance stability are discussed,alongside recent advancements in charge transport layers,electrodes,and interfaces aimed at reducing environmental degradation and improving energy level alignment for efficient charge extraction.The importance of accelerated aging tests and the establishment of standardized protocols is underscored for accurately predicting device lifetimes and identifying failure mechanisms,thereby ensuring stability under real-world conditions.Furthermore,a comprehensive techno-economic analysis evaluates how advancements in materials and strategic innovations influence efficiency,durability,and cost,which are critical for the commercial adoption of PSCs.This review delineates the essential steps required to transition PSC technology from laboratory-scale research to widespread commercialization within the global photovoltaic industry.
基金support by the National Key Research and Development Program of China(No.2022YFA1204800)the National Natural Science Foundation of China(No.U21A2078)the Scientific Research Funds of Huaqiao University(No.23BS109).
文摘As an inherent current-driven device,the luminous intensity of a single-unit perovskite light-emitting diode is directly proportional to the current density.However,this relationship can lead to a deterioration in the operational lifetime of the device at high current densities.In contrast,a tandem device structure,not only requires less current to achieve equivalent brightness compared to a single-unit device but also nearly achieves the combined efficiencies of each light-emitting unit.Herein,we present recommendations and protocols designed to facilitate the fabrication of all-tandem perovskite light-emitting diode,with the aim of benefiting both the research and industrial communities.
基金supported by the Special Guiding Program for Technology Innovation of Shaanxi Province (Grant No. 2022GF05-02)the National Natural Science Foundation of China (Grant No. 21971117)+7 种基金the Nankai University Central University Function Research Fund (Grant No.63186005)the Tianjin Rare Earth Key Laboratory of Materials and Application (Grant No. ZB19500202)the Open Fund of State Key Laboratory of Rare Earth Resources Utilization (Grant No. RERU2019001)the Project111 (Grant No. B18030)the Collaborative Innovation Project of BeijingTianjin-Hebei (Grant No. 19YFSLQY00030)the National Key R&D Program of China (Grant No. 2021YFA1202400)the Outstanding Youth of Tianjin Natural Science(Grant No. 20JCJQJC00130)the Key Project of Tianjin Natural Science Foundation (Grant No.20JCZDJC00650)
文摘The development of lithium-ion solid electrolyte provides new ideas for solving the safety problems of secondary lithium-ion batteries(LIB) and, at the same time, the improvement of energy density. However, the consequent solid-solid interfacial problems have become a typical bottleneck to the performance. It has been considered that the space charge layer(SCL) formed at the interface to balance the sharp electrochemical inherent difference of properties is one of the most important factors that affect the ion transportation along and across the interface. Its existence may hinder ion transportation and increase the interfacial impedance but may also help to provide a new percolation path for lithium ion and so to enhance the ion migration. However the mechanism of SPL formation and its regulation on ion transport is not very clear, so it has raised a lot of attention and interest from LIB researchers. The purpose of this article is to try to gain some knowledge of SCL and, at the same time to browse through the related research in recent years. Hopefully, it may help those interested in solid electrolyte development for all-solidstate lithium-ion batteries(ASSB) in the future.
基金financially supported by the National Natural Science Foundation of China(62075043)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ126)。
文摘Recently,solution-processed quantum dot lightemitting diodes(QLEDs)have emerged as a promising candidate for next-generation lighting and display devices.However,when given a constant voltage or current,the QLEDs need a certain working time to reach their maximum brightness.Such positive aging challenge,dramatically reducing the response speed of the device and causing a luminescence delay,is urgent to be investigated and resolved.In the current work,we introduce a charge-storage layer architecture by inserting copper(I)thiocyanate(CuSCN)between the organic holeinjection layer and hole-transport layer.The extracted holes will be released during the next electrical signal stimulation to increase the efficiency of charge transport.As a result,the response speed of the QLEDs is improved by an order of magnitude.In addition,by inserting an inorganic CuSCN layer,the efficiency,lifetime,and environmental stability of red/green/blue full-color QLEDs are enhanced simultaneously.Moreover,this work provides a generic strategy for the fabrication of fast-response and high-efficiency full-color QLEDs without luminescence delay,which plays a critical role in the practical industrialization of QLEDs.
