Perovskite solar cells(PSCs)have emerged as a promising photovoltaic technology with their rapid improvement in power conversion efficiency from 3.8%to 26.7%.However,the unsatisfactory stability is still a major hurdl...Perovskite solar cells(PSCs)have emerged as a promising photovoltaic technology with their rapid improvement in power conversion efficiency from 3.8%to 26.7%.However,the unsatisfactory stability is still a major hurdle to the future commercialization of PSCs.Among various causes of instability,oxygen and photo-induced instability are indispensable aspects to be considered,especially there is a growing demand of manufacturing PSCs with low-cost environmental conditions.This review aims to provide a timely and comprehensive summary of the investigations related to the oxygen-and photo-induced decay(OP-decay)in perovskites.Key factors affecting the OP decay pathways and decay rate have been discussed.Techniques for the analysis of oxygen and photo-induced decay processes are included.Strategies for improving photo-oxygen stability have been summarized,from the aspects of suppressing the generation yield of superoxide,protecting perovskites from the generated superoxide,and slowing down the oxygen penetration,respectively.展开更多
Interfaces play critical roles in electronic devices and provide great diversity of film morphology and device performance.We retrospect the substrate mediated vacuum film growth of benchmark high mobility material 2,...Interfaces play critical roles in electronic devices and provide great diversity of film morphology and device performance.We retrospect the substrate mediated vacuum film growth of benchmark high mobility material 2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene(C8-BTBT)and the interface electronic structures.The film growth of C8-BTBT molecules is diversified depending on the substrate-molecule and molecule-molecule interactions.On atomic smooth substrates C8-BTBT film grows in layer-by-layer mode while on coarse substrate it grows in islands mode.The initial molecular layer at dielectric,semiconductor and conductive substrates displays slight different lattice structure.The initial molecule orientation depends on the substrate and will gradually change to standing up configuration as in bulk phase.C8-BTBT behaves as electron donor when contacting with dielectric and stable conductive materials.This usually induces a dipole layer pointing to C8-BTBT and an upward bend bending in C8-BTBT side toward the interface.Although it is air stable,C8-BTBT is chemically reactive with some transition metals and compounds.The orientation change from lying down to standing up in the film usually leads to decrease of ionization potential.The article provides insights to the interface physical and chemical processes and suggestions for optimal design and fabrication of C8-BTBT based devices.展开更多
Self-diffraction appears when the strong laser goes through two-dimensional material suspension,and this spatial self-phase modulation(SPPM)phenomenon can be used to measure nonlinear optical parameters and achieve op...Self-diffraction appears when the strong laser goes through two-dimensional material suspension,and this spatial self-phase modulation(SPPM)phenomenon can be used to measure nonlinear optical parameters and achieve optical switch.At present,the mechanism of SPPM is still ambiguous.The debate mainly focuses on whether the phenomenon is caused by the nonlinear refractive index of the two-dimensional material or the thermal effect of the laser.The lack of theory limits the dimension of the phase modulation to the radius of the diffraction ring and the vertical imbalance.Therefore,it is urgent to establish a unified and universal SSPM theoretical system of two-dimensional material.展开更多
基金Project(62104261)supported by the National Natural Science Foundation of ChinaProject(2023JJ40695)supported by the Program of Natural Science Foundation of Hunan Province,China。
文摘Perovskite solar cells(PSCs)have emerged as a promising photovoltaic technology with their rapid improvement in power conversion efficiency from 3.8%to 26.7%.However,the unsatisfactory stability is still a major hurdle to the future commercialization of PSCs.Among various causes of instability,oxygen and photo-induced instability are indispensable aspects to be considered,especially there is a growing demand of manufacturing PSCs with low-cost environmental conditions.This review aims to provide a timely and comprehensive summary of the investigations related to the oxygen-and photo-induced decay(OP-decay)in perovskites.Key factors affecting the OP decay pathways and decay rate have been discussed.Techniques for the analysis of oxygen and photo-induced decay processes are included.Strategies for improving photo-oxygen stability have been summarized,from the aspects of suppressing the generation yield of superoxide,protecting perovskites from the generated superoxide,and slowing down the oxygen penetration,respectively.
基金Project(2017YFA0206602)supported in part by the National Key Research and Development Program of China。
文摘Interfaces play critical roles in electronic devices and provide great diversity of film morphology and device performance.We retrospect the substrate mediated vacuum film growth of benchmark high mobility material 2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene(C8-BTBT)and the interface electronic structures.The film growth of C8-BTBT molecules is diversified depending on the substrate-molecule and molecule-molecule interactions.On atomic smooth substrates C8-BTBT film grows in layer-by-layer mode while on coarse substrate it grows in islands mode.The initial molecular layer at dielectric,semiconductor and conductive substrates displays slight different lattice structure.The initial molecule orientation depends on the substrate and will gradually change to standing up configuration as in bulk phase.C8-BTBT behaves as electron donor when contacting with dielectric and stable conductive materials.This usually induces a dipole layer pointing to C8-BTBT and an upward bend bending in C8-BTBT side toward the interface.Although it is air stable,C8-BTBT is chemically reactive with some transition metals and compounds.The orientation change from lying down to standing up in the film usually leads to decrease of ionization potential.The article provides insights to the interface physical and chemical processes and suggestions for optimal design and fabrication of C8-BTBT based devices.
基金Project(6187031976)supported by the National Natural Science Foundation of China
文摘Self-diffraction appears when the strong laser goes through two-dimensional material suspension,and this spatial self-phase modulation(SPPM)phenomenon can be used to measure nonlinear optical parameters and achieve optical switch.At present,the mechanism of SPPM is still ambiguous.The debate mainly focuses on whether the phenomenon is caused by the nonlinear refractive index of the two-dimensional material or the thermal effect of the laser.The lack of theory limits the dimension of the phase modulation to the radius of the diffraction ring and the vertical imbalance.Therefore,it is urgent to establish a unified and universal SSPM theoretical system of two-dimensional material.
