Lead chalcohalides(PbYX,X=Cl,Br,I;Y=S,Se)is an extension of the classic Pb chalcogenides(PbY).Constructing the heterogeneous integration with PbYX and PbY material systems makes it possible to achieve significantly im...Lead chalcohalides(PbYX,X=Cl,Br,I;Y=S,Se)is an extension of the classic Pb chalcogenides(PbY).Constructing the heterogeneous integration with PbYX and PbY material systems makes it possible to achieve significantly improved optoelectronic performance.In this work,we studied the effect of introducing halogen precursors on the structure of classical PbS nanocrystals(NCs)during the synthesis process and realized the preparation of PbS/Pb_(3)S_(2)X_(2) core/shell structure for the first time.The core/shell structure can effectively improve their optical properties.Furthermore,our approach enables the synthesis of Pb_(3)S_(2)Br_(2) that had not yet been reported.Our results not only provide valuable insights into the heterogeneous integration of PbYX and PbY materials to elevate material properties but also provide an effective method for further expanding the preparation of PbYX material systems.展开更多
Recent advances in all-inorganic perovskite semiconductors have garnered significant research interest due to their potential for high-performance optoelectronic devices and enhanced stability under harsh environmenta...Recent advances in all-inorganic perovskite semiconductors have garnered significant research interest due to their potential for high-performance optoelectronic devices and enhanced stability under harsh environmental conditions.A deeper understanding of their structural,chemical,and physical properties has driven notable progress in addressing challenges related to electrical characteristics,reproducibility,and long-term operational stability in perovskite-based memristors.These advancements have been realized through composition engineering,dimensionality modulation,thin-film processing,and device optimization.This review concisely summarizes recent developments in all-inorganic perovskite memristors,highlighting their diverse material properties,device performance,and applications in artificial synapses and logic operations.We discuss key resistance-switching mechanisms,optimization strategies,and operational capabilities while outlining remaining challenges and future directions for perovskitebased memory technologies.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
Multiple exciton generation （MEG） dynamics in colloidal PbS quantum dots （QDs） characterized with an im- proved transient grating （TG） technique will be reported. Only one peak soon after optical absorption and ...Multiple exciton generation （MEG） dynamics in colloidal PbS quantum dots （QDs） characterized with an im- proved transient grating （TG） technique will be reported. Only one peak soon after optical absorption and a fast decay within 1 ps can be observed in the TG kinetics when the photon energy of the pump light hv is smaller than 2.7Eg （Eg： band gap between LUMO and HOMO in the QDs）, which corresponds to hot carrier cooling. When hv is greater than 2.7Eg, however, after the initial peak, the TG signal decreases first and soon increases, and then a new peak appears at about 2 to 3 ps. The initial peak and the new peak correspond to hot carriers at the higher excited state and MEG at the lowest excited state, respectively. By proposing a theoretical model, we can calculate the hot carrier cooling time constant and MEG occurrence time constant quantitatively. When MEG does not happen for hv smaller than 2.7Eg, hot carrier cools with a time con- stant of 400 fs. When MEG occurs for hv larger than 2.7Eg, hot carrier cools with a time constant as small as 200 fs, while MEG occurs with a time constant of 600 fs. The detailed hot carrier cooling and MEG occurrence dynamics characterized in this work would shed light on the further understanding of MEG mechanism of various type of semiconductor QDs.展开更多
A novel hole-transport material(HTM)based on an anthradithiophene central bridge named BTPA-7 is developed.In comparison to spiro-OMeTAD(2,2’,7,7’-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene),the sy...A novel hole-transport material(HTM)based on an anthradithiophene central bridge named BTPA-7 is developed.In comparison to spiro-OMeTAD(2,2’,7,7’-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene),the synthetic steps of BTPA-7 are greatly reduced from 6 to 3 and the synthetic cost of BTPA-7 is nearly a half that of spiro-OMeTAD.Moreover,BTPA-7 exhibits a relatively lower conductivity but higher hole mobility and higher glass transition temperature(Tg)than spiro-OMeTAD.Compared with the photovolatic performance for spiro-OMeTAD,FA0.85MA0.15PbI3 and MAPbI3 PSC devices based on BTPA-7 exhibit slightly lower PCEs with the values of 17.58%(18.88%for spiro-OMeTAD)and 11.90%(13.25%for spiro-OMeTAD),respectively.Nevertheless,a dramatically higher JSC of PSC based on BTPA-7is achieved,which arises from the higher hole mobility of BTPA-7.In addition,the relatively hydrophobic character of BTPA-7 eventually enhances the PSC device stability.Lower cost,higher hole mobility,higher Tg,satisfactory photovoltaic performance,and superior device stability of BTPA-7 can be utilized as a substitute for spiro-OMeTAD in PSCs.展开更多
Tin-lead alloyed perovskite nanocrystals(PNCs)offer a promising pathway toward low-toxicity and air-stable light-emitting devices.However,substantial energetic disorder has thus far hindered their lighting application...Tin-lead alloyed perovskite nanocrystals(PNCs)offer a promising pathway toward low-toxicity and air-stable light-emitting devices.However,substantial energetic disorder has thus far hindered their lighting applications compared to pure lead-based PNCs.A fundamental understanding of this disorder and its impact on optical properties is crucial for overcoming this limitation.Here,using temperature-dependent static and transient absorption spectroscopy,we meticulously distinguish the contributions of static disorder(including defects,impurities,etc.)and dynamic disorder(carrier-phonon interactions).We reveal how these disorders shape band-tail structure and ultimately influence inter-band carrier recombination behaviors.Surprisingly,we find that static and dynamic disorder primarily control band-tail defect states and bandgap renormalization,respectively,which together modulate fast carrier trapping and slow band-band recombination rates.Furthermore,we link these disorders to the tin-induced symmetry-lowering distortions in tin-lead alloyed PNCs.These findings illuminate critical design principles for highly luminescent,low-toxicity tin-lead PNCs,accelerating their adoption in optoelectronic applications.展开更多
Tuning the conjugated bridges between the electron-donor and electron-acceptor moieties plays a crucial role in enhancing the memristive properties of organic materials,yet it is rarely reported.Herein,we designed and...Tuning the conjugated bridges between the electron-donor and electron-acceptor moieties plays a crucial role in enhancing the memristive properties of organic materials,yet it is rarely reported.Herein,we designed and synthesized four donor-acceptor(D-A)organic small molecules,namely 4,7-bis(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)benzo[c][1,2,5]thiadiazole(DF-BT),4,7-bis((4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)ethynyl)benzo[c][1,2,5]thiadiazole(DF-ynl-BT),4,7-bis(5-(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole(DF-Th-BT),and 4,7-bis((5-(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)thiophen-2-yl)ethynyl)benzo[c][1,2,5]thiadiazole(DF-Th-ynl-BT),featuring unique conjugated bridges.These molecules were employed as active layers in resistive random-access memory(RRAM)devices to systematically investigate the influence of conjugation bridges on the electrical parameters.The results revealed that devices based on DF-BT,DF-ynl-BT,and DF-Th-BT exhibited write-once-read-many-times(WORM)characteristics,while the DF-Th-ynl-BT-based device demonstrated stable Flash-type switching behavior.Compared to DF-BT,memory devices utilizing DF-ynl-BT,DF-Th-BT,and DF-Th-ynl-BT,which incorporate additional conjugated bridges,exhibited nonvolatile memory properties with reduced threshold voltages,an improved ON/OFF current ratio,enhanced stability,and better uniformity.These findings demonstrated that tailoring the conjugated bridges in D-A molecules can effectively modulate resistive memory behavior and enhance device performance.Furthermore,the DF-Th-ynl-BT-based device was successfully integrated into logic gate circuits and display functions,highlighting its significant potential for applications in artificial intelligence(AI)neural networks.展开更多
Solution-processed colloidal quantum dot solar cells(CQDSCs) is a promising candidate for new generation solar cells.To obtain stable and high performance lead sulfide(PbS)-based CQDSCs,high carrier mobility and low n...Solution-processed colloidal quantum dot solar cells(CQDSCs) is a promising candidate for new generation solar cells.To obtain stable and high performance lead sulfide(PbS)-based CQDSCs,high carrier mobility and low non-radiative recombination center density in the PbS CQDs active layer are required.In order to effectively improve the carrier mobility in PbS CQDs layer of CQDSCs,butylamine(BTA)-modified graphene oxide(BTA@GO) is first utilized in PbS-PbX2(X=I-,Br-) CQDs ink to deposit the active layer of CQDSCs through one-step spin-coating method.Such surface treatment of GO dramatically upholds the intrinsic superior hole transfer peculiarity of GO and attenuates the hydrophilicity of GO in order to allow for its good dispersibility in ink solvent.The introduction of B TA@GO in CQDs layer can build up a bulk nano-heterojunction architecture,which provides a smooth charge carrier transport channel in turn improves the carrier mobility and conductivity,extends the carriers lifetime and reduces the trap density of PbS-PbX2 CQDs film.Finally,the BTA@GO/PbS-PbX2 hybrid CQDs film-based relatively large-area(0.35 cm2) CQDSCs shows a champion power conversion efficiency of 11.7% which is increased by 23.1% compared with the control device.展开更多
Lead sulfide colloidal quantum dots(PbS CQDs),as a nov-el material for optoelectronic devices,have lately attracted a lot of attention mainly because of their tunable optoelectron-ic characteristics and low-temperatur...Lead sulfide colloidal quantum dots(PbS CQDs),as a nov-el material for optoelectronic devices,have lately attracted a lot of attention mainly because of their tunable optoelectron-ic characteristics and low-temperature film preparation.PbS CQDs can harvest infrared(IR)light in single-junction,multi-junction,and tandem solar cells[1−3].Thanks to the combina-tion of surface chemical engineering and device structure en-gineering,the power conversion efficiency(PCE)for PbS CQDs solar cells has increased from less than 1%in 2005 to current 13.8%[4,5].展开更多
In recent years,myoelectric hands have become multi-degree-of-freedom(DOF)devices,which are controlled via machine learning methods.However,currently,learning data for myoelectric hands are gathered manually and thus ...In recent years,myoelectric hands have become multi-degree-of-freedom(DOF)devices,which are controlled via machine learning methods.However,currently,learning data for myoelectric hands are gathered manually and thus tend to be of low quality.Moreover,in the case of infants,gathering accurate learning data is nearly impossible because of the difficulty of communicating with them.Therefore,a method that automatically corrects errors in the learning data is necessary.Myoelectric hands are wearable robots and thus have volumetric and weight constraints that make it infeasible to store large amounts of data or apply complex processing methods.Compared with general machine learning methods such as image processing,those for myoelectric hands have limitations on the data storage,although the amount of data to be processed is quite large.If we can use this huge amount of processing data to correct the learning data without storing the processing data,the machine learning performance is expected to improve.We then propose a method for correcting the learning data through utilisation of the signals acquired during the use of the myoelectric hand.The proposed method is inspired by“survival of the fittest.”The effectiveness of the method was verified through offline analysis.The method reduced the amount of learning data and learning time by approximately a factor of 10 while maintaining classification rates.The classification rates improved for one participant but slightly deteriorated on average among all participants.To solve this problem,verifying the method via interactive learning will be necessary in the future.展开更多
Fast and non-destructive analysis of material defect is a crucial demand for semiconductor devices.Herein,we are devoted to exploring a solar-cell defect analysis method based on machine learning of the modulated tran...Fast and non-destructive analysis of material defect is a crucial demand for semiconductor devices.Herein,we are devoted to exploring a solar-cell defect analysis method based on machine learning of the modulated transient photovoltage(m-TPV)measurement.The perturbation photovoltage generation and decay mechanism of the solar cell is firstly clarified for this study.High-throughput electrical transient simulations are further carried out to establish a database containing millions of m-TPV curves.This database is subsequently used to train an artificial neural network to correlate the m-TPV and defect properties of the perovskite solar cell.A Back Propagation neural network has been screened out and applied to provide a multiple parameter defect analysis of the cell.This analysis reveals that in a practical solar cell,compared to the defect density,the charge capturing cross-section plays a more critical role in influencing the charge recombination properties.We believe this defect analysis approach will play a more important and diverse role for solar cell studies.展开更多
Great photoelectric properties can herald the high potentials of CsPbBr3 nanocrystals(NCs)to function as the fluorescent probes for early tumor diagnosis.However,the intrinsic water vulnerability of CsPbBr3 NCs highly...Great photoelectric properties can herald the high potentials of CsPbBr3 nanocrystals(NCs)to function as the fluorescent probes for early tumor diagnosis.However,the intrinsic water vulnerability of CsPbBr3 NCs highly restricts their biomedical applications.To conquer this challenge,we herein introduce a nature inspired"stress-response"method to tightly encapsulate CsPbBr3 into SiO2 nano-shells that can dramatically improve the water stability of CsPbBr3@SiO2 nanoparticles for over 48 h.We further highlighted the advantageous features of CsPbBr3@SiO2 by using them as the fluorescent probes for CT26 tumor cell imaging with their high water stability,biocompatibility,and low cytotoxicity.Our work for the first time exhibited the potential of lead halide perovskite NCs for tumor diagnosis,and can highly anticipate the further in vivo biomedical applications that light up live cells.展开更多
Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to...Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to the direct production of CQD inks.However,the photoelectric conversion efficiency(PCE)of lead chalcogenide CQDSCs is presently close to 14%,well below the commercialization target(20%),which is only 41%of the theoretical Shockley-Queisser limit efficiency.In this study,the different losses of open-circuit voltage(V_(oc)),fill factor(FF),and short circuit current density(J_(sc))for current CQDSCs are systematically discussed,as well as the percentage and likely causes of each loss.Then the primary reasons for the CQDSCs’performance constraints are highlighted.Following that,we focus on the CQDSCs interfaces(i.e.,CQD/CQD,CQD/HTL,and ETL/CQD)and explore viable ways to reduce device performance loss.Finally,based on the discussion above,we propose many enhancements to significantly solve numerous major obstacles impeding device performance to boost the PCE of CQDSCs for future commercialization significantly.展开更多
We use a transient-grating （TG） process in a Kerr bulk medium to clean a femtosecond laser pulse. Using the technique, the temporal contrast of the generated TG signal is improved by more than two orders of magnitud...We use a transient-grating （TG） process in a Kerr bulk medium to clean a femtosecond laser pulse. Using the technique, the temporal contrast of the generated TG signal is improved by more than two orders of magnitude in comparison with the incident pulse in a 0.5-mm-thick fused silica plate. The laser spectrum is smoothed and broadened, and the pulse duration is shortened simultaneously. We expect to extend this technique to a clean pulse with broadband spectral bandwidth at a wide spectral range because it is a phase-matched process.展开更多
Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conv...Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0110300)the National Natural Science Foundation of China(Grant Nos.52372215,92163114,and 52202274)+5 种基金the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20230504)the Special Fund for the"Dual Carbon"Science and Technology Innovation of Jiangsu province(Industrial Prospect and Key Technology Research program)(Grant Nos.BE2022023 and BE2022021)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.21KJA430004)Gusu Innovation and Entre preneurship Leading Talent Program(Grant No.ZXL2022451)the China Postdoctoral Science Foundation(Grant No.2023M732523)supported by Suzhou Key Laboratory of Functional Nano&Soft Materials,Collaborative Innovation Center of Suzhou Nano Science&Technology,the 111 Project.
文摘Lead chalcohalides(PbYX,X=Cl,Br,I;Y=S,Se)is an extension of the classic Pb chalcogenides(PbY).Constructing the heterogeneous integration with PbYX and PbY material systems makes it possible to achieve significantly improved optoelectronic performance.In this work,we studied the effect of introducing halogen precursors on the structure of classical PbS nanocrystals(NCs)during the synthesis process and realized the preparation of PbS/Pb_(3)S_(2)X_(2) core/shell structure for the first time.The core/shell structure can effectively improve their optical properties.Furthermore,our approach enables the synthesis of Pb_(3)S_(2)Br_(2) that had not yet been reported.Our results not only provide valuable insights into the heterogeneous integration of PbYX and PbY materials to elevate material properties but also provide an effective method for further expanding the preparation of PbYX material systems.
基金supported by the JST SPRING Grant number JPMJSP2131funded by the Research Fellow Scheme from The Chinese University of Hong KongUniversiti Teknologi Malaysia AJ090000.6700.09453-Tabung Pembayaran Lantikan Skim Prominent Visiting Researcher Scheme JTNCPI。
文摘Recent advances in all-inorganic perovskite semiconductors have garnered significant research interest due to their potential for high-performance optoelectronic devices and enhanced stability under harsh environmental conditions.A deeper understanding of their structural,chemical,and physical properties has driven notable progress in addressing challenges related to electrical characteristics,reproducibility,and long-term operational stability in perovskite-based memristors.These advancements have been realized through composition engineering,dimensionality modulation,thin-film processing,and device optimization.This review concisely summarizes recent developments in all-inorganic perovskite memristors,highlighting their diverse material properties,device performance,and applications in artificial synapses and logic operations.We discuss key resistance-switching mechanisms,optimization strategies,and operational capabilities while outlining remaining challenges and future directions for perovskitebased memory technologies.
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supported by MEXT KAKENHI Grant no. 26286013the PRESTO program Photoenergy conversion systems and materials for the next generation solar cells,Japan Science and Technology Agency (JST)
文摘Multiple exciton generation （MEG） dynamics in colloidal PbS quantum dots （QDs） characterized with an im- proved transient grating （TG） technique will be reported. Only one peak soon after optical absorption and a fast decay within 1 ps can be observed in the TG kinetics when the photon energy of the pump light hv is smaller than 2.7Eg （Eg： band gap between LUMO and HOMO in the QDs）, which corresponds to hot carrier cooling. When hv is greater than 2.7Eg, however, after the initial peak, the TG signal decreases first and soon increases, and then a new peak appears at about 2 to 3 ps. The initial peak and the new peak correspond to hot carriers at the higher excited state and MEG at the lowest excited state, respectively. By proposing a theoretical model, we can calculate the hot carrier cooling time constant and MEG occurrence time constant quantitatively. When MEG does not happen for hv smaller than 2.7Eg, hot carrier cools with a time con- stant of 400 fs. When MEG occurs for hv larger than 2.7Eg, hot carrier cools with a time constant as small as 200 fs, while MEG occurs with a time constant of 600 fs. The detailed hot carrier cooling and MEG occurrence dynamics characterized in this work would shed light on the further understanding of MEG mechanism of various type of semiconductor QDs.
基金financially supported by the National Key Research and Development Program of China(2016YFA0202403)the National University Research Fund(GK261001009)+7 种基金the Changjiang Scholar and Innovative Research Team(IRT_14R33)the Overseas Talent Recruitment Project(B14041)the Chinese National 1000talent plan program(Grant No.111001034)the JSPS Kakenhi grants(No.26288113 and 15K05486)support from the Strategic Research Foundation at Private Universities(Nihon University and the MEXT,Japan)the Natural Science Foundation of Shaanxi Province(2019JQ-423)the Fundamental Research Funds for the Central Universities(GK201903053)Key Lab of photovoltaic and Energy Conservation Materials,Chinese Academy of Sciences(No.PECL2019KF019)。
文摘A novel hole-transport material(HTM)based on an anthradithiophene central bridge named BTPA-7 is developed.In comparison to spiro-OMeTAD(2,2’,7,7’-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene),the synthetic steps of BTPA-7 are greatly reduced from 6 to 3 and the synthetic cost of BTPA-7 is nearly a half that of spiro-OMeTAD.Moreover,BTPA-7 exhibits a relatively lower conductivity but higher hole mobility and higher glass transition temperature(Tg)than spiro-OMeTAD.Compared with the photovolatic performance for spiro-OMeTAD,FA0.85MA0.15PbI3 and MAPbI3 PSC devices based on BTPA-7 exhibit slightly lower PCEs with the values of 17.58%(18.88%for spiro-OMeTAD)and 11.90%(13.25%for spiro-OMeTAD),respectively.Nevertheless,a dramatically higher JSC of PSC based on BTPA-7is achieved,which arises from the higher hole mobility of BTPA-7.In addition,the relatively hydrophobic character of BTPA-7 eventually enhances the PSC device stability.Lower cost,higher hole mobility,higher Tg,satisfactory photovoltaic performance,and superior device stability of BTPA-7 can be utilized as a substitute for spiro-OMeTAD in PSCs.
基金supported by JSPS MEXT KAKENHI Grant Numbers(20H02565,17H02736)NEDO project and JST project(JPMJMI22E2).
文摘Tin-lead alloyed perovskite nanocrystals(PNCs)offer a promising pathway toward low-toxicity and air-stable light-emitting devices.However,substantial energetic disorder has thus far hindered their lighting applications compared to pure lead-based PNCs.A fundamental understanding of this disorder and its impact on optical properties is crucial for overcoming this limitation.Here,using temperature-dependent static and transient absorption spectroscopy,we meticulously distinguish the contributions of static disorder(including defects,impurities,etc.)and dynamic disorder(carrier-phonon interactions).We reveal how these disorders shape band-tail structure and ultimately influence inter-band carrier recombination behaviors.Surprisingly,we find that static and dynamic disorder primarily control band-tail defect states and bandgap renormalization,respectively,which together modulate fast carrier trapping and slow band-band recombination rates.Furthermore,we link these disorders to the tin-induced symmetry-lowering distortions in tin-lead alloyed PNCs.These findings illuminate critical design principles for highly luminescent,low-toxicity tin-lead PNCs,accelerating their adoption in optoelectronic applications.
基金supported by the financial support from the National Natural Science Foundation of China(Grant Nos.:62174116 and 61774109)the start-up fund from Shanghai University.
文摘Tuning the conjugated bridges between the electron-donor and electron-acceptor moieties plays a crucial role in enhancing the memristive properties of organic materials,yet it is rarely reported.Herein,we designed and synthesized four donor-acceptor(D-A)organic small molecules,namely 4,7-bis(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)benzo[c][1,2,5]thiadiazole(DF-BT),4,7-bis((4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)ethynyl)benzo[c][1,2,5]thiadiazole(DF-ynl-BT),4,7-bis(5-(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole(DF-Th-BT),and 4,7-bis((5-(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)thiophen-2-yl)ethynyl)benzo[c][1,2,5]thiadiazole(DF-Th-ynl-BT),featuring unique conjugated bridges.These molecules were employed as active layers in resistive random-access memory(RRAM)devices to systematically investigate the influence of conjugation bridges on the electrical parameters.The results revealed that devices based on DF-BT,DF-ynl-BT,and DF-Th-BT exhibited write-once-read-many-times(WORM)characteristics,while the DF-Th-ynl-BT-based device demonstrated stable Flash-type switching behavior.Compared to DF-BT,memory devices utilizing DF-ynl-BT,DF-Th-BT,and DF-Th-ynl-BT,which incorporate additional conjugated bridges,exhibited nonvolatile memory properties with reduced threshold voltages,an improved ON/OFF current ratio,enhanced stability,and better uniformity.These findings demonstrated that tailoring the conjugated bridges in D-A molecules can effectively modulate resistive memory behavior and enhance device performance.Furthermore,the DF-Th-ynl-BT-based device was successfully integrated into logic gate circuits and display functions,highlighting its significant potential for applications in artificial intelligence(AI)neural networks.
基金supported by the Japan Science and Technology Agency(JST)CREST programBeijing Advanced Innovation Center for Future Urban Design,Beijing University of Civil Engineering and Architecture(Grant UDC2018031121)+3 种基金the MEXT KAKENHI(Grant 17H02736)the Natural Science Foundation of Shaanxi Province(2019JQ-423)the Fundamental Research Funds for the Central Universities(GK201903053)Key Lab of Photovoltaic and Energy Conservation Materials,Chinese Academy of Sciences(No.PECL2019KF019)for financial support.
文摘Solution-processed colloidal quantum dot solar cells(CQDSCs) is a promising candidate for new generation solar cells.To obtain stable and high performance lead sulfide(PbS)-based CQDSCs,high carrier mobility and low non-radiative recombination center density in the PbS CQDs active layer are required.In order to effectively improve the carrier mobility in PbS CQDs layer of CQDSCs,butylamine(BTA)-modified graphene oxide(BTA@GO) is first utilized in PbS-PbX2(X=I-,Br-) CQDs ink to deposit the active layer of CQDSCs through one-step spin-coating method.Such surface treatment of GO dramatically upholds the intrinsic superior hole transfer peculiarity of GO and attenuates the hydrophilicity of GO in order to allow for its good dispersibility in ink solvent.The introduction of B TA@GO in CQDs layer can build up a bulk nano-heterojunction architecture,which provides a smooth charge carrier transport channel in turn improves the carrier mobility and conductivity,extends the carriers lifetime and reduces the trap density of PbS-PbX2 CQDs film.Finally,the BTA@GO/PbS-PbX2 hybrid CQDs film-based relatively large-area(0.35 cm2) CQDSCs shows a champion power conversion efficiency of 11.7% which is increased by 23.1% compared with the control device.
基金This research was supported by the Japan Science and Technology Agency(JST)Mirai program(JPMJMI17EA),MEXT KAKENHI Grant(26286013,17H02736)L.Ding thanks the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032 and 21961160720)for financial support.
文摘Lead sulfide colloidal quantum dots(PbS CQDs),as a nov-el material for optoelectronic devices,have lately attracted a lot of attention mainly because of their tunable optoelectron-ic characteristics and low-temperature film preparation.PbS CQDs can harvest infrared(IR)light in single-junction,multi-junction,and tandem solar cells[1−3].Thanks to the combina-tion of surface chemical engineering and device structure en-gineering,the power conversion efficiency(PCE)for PbS CQDs solar cells has increased from less than 1%in 2005 to current 13.8%[4,5].
基金supported by the“Development Promotion Project for Practical Use of Welfare Equipment”from the New Energy and Industrial Technology Development Organization(NEDO).
文摘In recent years,myoelectric hands have become multi-degree-of-freedom(DOF)devices,which are controlled via machine learning methods.However,currently,learning data for myoelectric hands are gathered manually and thus tend to be of low quality.Moreover,in the case of infants,gathering accurate learning data is nearly impossible because of the difficulty of communicating with them.Therefore,a method that automatically corrects errors in the learning data is necessary.Myoelectric hands are wearable robots and thus have volumetric and weight constraints that make it infeasible to store large amounts of data or apply complex processing methods.Compared with general machine learning methods such as image processing,those for myoelectric hands have limitations on the data storage,although the amount of data to be processed is quite large.If we can use this huge amount of processing data to correct the learning data without storing the processing data,the machine learning performance is expected to improve.We then propose a method for correcting the learning data through utilisation of the signals acquired during the use of the myoelectric hand.The proposed method is inspired by“survival of the fittest.”The effectiveness of the method was verified through offline analysis.The method reduced the amount of learning data and learning time by approximately a factor of 10 while maintaining classification rates.The classification rates improved for one participant but slightly deteriorated on average among all participants.To solve this problem,verifying the method via interactive learning will be necessary in the future.
基金supported by the National Natural Science Foundation of China(52222212,52227803,52242201,51872321,11874402,52072402).
文摘Fast and non-destructive analysis of material defect is a crucial demand for semiconductor devices.Herein,we are devoted to exploring a solar-cell defect analysis method based on machine learning of the modulated transient photovoltage(m-TPV)measurement.The perturbation photovoltage generation and decay mechanism of the solar cell is firstly clarified for this study.High-throughput electrical transient simulations are further carried out to establish a database containing millions of m-TPV curves.This database is subsequently used to train an artificial neural network to correlate the m-TPV and defect properties of the perovskite solar cell.A Back Propagation neural network has been screened out and applied to provide a multiple parameter defect analysis of the cell.This analysis reveals that in a practical solar cell,compared to the defect density,the charge capturing cross-section plays a more critical role in influencing the charge recombination properties.We believe this defect analysis approach will play a more important and diverse role for solar cell studies.
基金This work was supported primarily by the National Key Research and Development Program of China(No.2018YFE0208500)the Major Research Plan of the National Natural Science Foundation of China(No.91963206)+3 种基金the National Natural Science Foundation of China(Nos.U1508202 and 51627810)the Natural Science Foundation of Jiangsu Province(No.SBK2018022120),the open fund of Wuhan National Laboratory for Optoelectronics(No.2018WNLOKF020)the open fund of Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies(No.EEST2018-1)the civil aerospace technology preliminary research project of the State Administration of Science,Technology and Industry for National Defense.
文摘Great photoelectric properties can herald the high potentials of CsPbBr3 nanocrystals(NCs)to function as the fluorescent probes for early tumor diagnosis.However,the intrinsic water vulnerability of CsPbBr3 NCs highly restricts their biomedical applications.To conquer this challenge,we herein introduce a nature inspired"stress-response"method to tightly encapsulate CsPbBr3 into SiO2 nano-shells that can dramatically improve the water stability of CsPbBr3@SiO2 nanoparticles for over 48 h.We further highlighted the advantageous features of CsPbBr3@SiO2 by using them as the fluorescent probes for CT26 tumor cell imaging with their high water stability,biocompatibility,and low cytotoxicity.Our work for the first time exhibited the potential of lead halide perovskite NCs for tumor diagnosis,and can highly anticipate the further in vivo biomedical applications that light up live cells.
基金supported by the Japan Science and Technology Agency(JST)Mirai program(JPMJMI17EA)MEXT KAKENHI(Grant Nos.26286013,and 17H02736)。
文摘Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to the direct production of CQD inks.However,the photoelectric conversion efficiency(PCE)of lead chalcogenide CQDSCs is presently close to 14%,well below the commercialization target(20%),which is only 41%of the theoretical Shockley-Queisser limit efficiency.In this study,the different losses of open-circuit voltage(V_(oc)),fill factor(FF),and short circuit current density(J_(sc))for current CQDSCs are systematically discussed,as well as the percentage and likely causes of each loss.Then the primary reasons for the CQDSCs’performance constraints are highlighted.Following that,we focus on the CQDSCs interfaces(i.e.,CQD/CQD,CQD/HTL,and ETL/CQD)and explore viable ways to reduce device performance loss.Finally,based on the discussion above,we propose many enhancements to significantly solve numerous major obstacles impeding device performance to boost the PCE of CQDSCs for future commercialization significantly.
基金partially supported by the 21st Century COE program on "Coherent Optical Science"supported by the grant from the Ministry of Education(MOE) under the ATU Program at National Chiao Tung University+1 种基金project of the Laser Engineering, Osaka University, under contract subject B1-27the support of the Opening Funds of the State Key Laboratory of High Field Laser Physics in China
文摘We use a transient-grating （TG） process in a Kerr bulk medium to clean a femtosecond laser pulse. Using the technique, the temporal contrast of the generated TG signal is improved by more than two orders of magnitude in comparison with the incident pulse in a 0.5-mm-thick fused silica plate. The laser spectrum is smoothed and broadened, and the pulse duration is shortened simultaneously. We expect to extend this technique to a clean pulse with broadband spectral bandwidth at a wide spectral range because it is a phase-matched process.
基金the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21572041 and 21772030)for the financial support
文摘Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.
