The anti-polar solvent technique is an effec- tive way to improve the film quality in a perovskite solar cell. In this work, we reveal the reason why chloroben- zene （CBZ） plays an important role in controlling the ...The anti-polar solvent technique is an effec- tive way to improve the film quality in a perovskite solar cell. In this work, we reveal the reason why chloroben- zene （CBZ） plays an important role in controlling the crystallization process. By investigating the formation of intermediate phases in the precursor solution, we observed that the CH3NH3I （MAI）-PbI2-dimethylformamide （DMF） or MAI-PbI2-dimethylsulphoxide （DMSO） adducts have not yet formed until washed with non-polar solvent. The accelerated formation of intermediate phase yields high crystalline perovskite layers. Rapid solvent evaporation and retarded perovskite crystallization in one-step method are efficient to obtain high-quality perovskite films. Conse- quently, MAI-PbI2-DMSO intermediate shows neat rod-like structure with high crystallinity, which eventually transforms extremely dense and uniform perovskite films.展开更多
Researchers working in the field of photovoltaic are exploring novel materials for the efficient solar energy conversion.The prime objective of the discovery of every novel photovoltaic material is to achieve more ene...Researchers working in the field of photovoltaic are exploring novel materials for the efficient solar energy conversion.The prime objective of the discovery of every novel photovoltaic material is to achieve more energy yield with easy fabrication process and less production cost features.Perovskite solar cells (PSCs)delivering the highest efficiency in the passing years with different stoichiometry and fabrication modification have made this technology a potent candidate for future energy conversion materials.Till now,many studies have shown that the quality of active layer morphology,to a great extent,determines the performance of PSCs.The current and potential techniques of solvent engineering for good active layer morphology are mainly debated using primary solvent,co-solvent (Lewis acid-base adduct approach)and solvent additives.In this review,the dynamics of numerously reported solvents on the morphological characteristics of PSCs active layer are discussed in detail.The intention is to get a clear understanding of solvent engineering induced modifications on active layer morphology in PSC devices via different crystallization routes.At last,an attempt is made to draw a framework based on different solvent coordination properties to make it easy for screening the potent solvent contender for desired PSCs precursor for a better and feasible device.展开更多
Formamidinium lead halide(α-FAPbI3)with a broad light absorption spectrum,has recently received considerable attention in optoelectronic applications.However,the FAI-PbI2-DMSO(DMSO:dimethyl sulfoxide)intermediate ani...Formamidinium lead halide(α-FAPbI3)with a broad light absorption spectrum,has recently received considerable attention in optoelectronic applications.However,the FAI-PbI2-DMSO(DMSO:dimethyl sulfoxide)intermediate anisotropic fibers readily form a non-perovskite phase(δ-FAPbI3)and uncontrolled excess PbI2,which hinders the further increase in the efficiencies of solar cells.Caculations indicate that iodine defects in polycrystalline films would enlarge the perovskite tolerance factor and result in the formation of iodide Frenkel defects.Herein,we introduce a post-treatment technique to heal the as-prepared FAPbI3 thin layer and restrain the notoriousδ-FAPbI3 through vacancy filling.Furthermore,a new intermediate phase of FAI-PbI2-DMSO-FACl led to a high-quality perovskite layer with an enlarged average grain size that exceeded 2μm.Consequently,the power conversion efficiencies of FAPbI3 solar cells were significantly enhanced due to the high crystallity of the pureα-phase perovskite.Therefore,this method can be used to obtain high pure-black perovskite films and efficient solar cells.展开更多
To date, extensive research has been carried out,with considerable success, on the development of highperformance perovskite solar cells(PSCs). Owing to its wide absorption range and remarkable thermal stability, the ...To date, extensive research has been carried out,with considerable success, on the development of highperformance perovskite solar cells(PSCs). Owing to its wide absorption range and remarkable thermal stability, the mixedcation perovskite FAxMA1-xPbI3(formamidinium/methylammonium lead iodide) promises high performance. However, the ratio of the mixed cations in the perovskite film has proved difficult to control with precursor solution. In addition, the FAxMA1-xPbI3 films contain a high percentage of MA+and suffer from serious phase separation and high trap states, resulting in inferior photovoltaic performance. In this study, to suppress phase separation, a post-processing method was developed to partially nucleate before annealing, by treating the as-prepared intermediate phase FAI-Pb I2-DMSO(DMSO: dimethylsulfoxide) with mixed FAI/MAI solution. It was found that in the final perovskite, FA0.92MA0.08 PbI3, defects were substantially reduced because the analogous molecular structure initiated ion exchange in the post-processed thin perovskite films, which advanced partial nucleation. As a result, the increased light harvesting and reduced trap states contributed to the enhancement of open-circuit voltage and short-circuit current. The PSCs produced by the post-processing method presented reliable reproducibility, with a maximum power conversion efficiency of 20.80% and a degradation of ~30% for 80 days in standard atmospheric conditions.展开更多
The quality of the perovskite light absorption layer plays a dynamic role in the photovoltaic properties of solar cells.The existing methods to prepare methylammonium lead iodide(MAPbI3)films render substantial struct...The quality of the perovskite light absorption layer plays a dynamic role in the photovoltaic properties of solar cells.The existing methods to prepare methylammonium lead iodide(MAPbI3)films render substantial structural defect density,particularly at the grain boundaries and film surface,constituting a challenge that hinders the further optoelectronic enhancement of perovskite solar cells.Herein,a unique approach was introduced:using a simple ethylammonium chloride(EACl)additive in perovskite precursor mixture to produce high-quality MAPbI3 thin films.The results indicated that EACl could encourage perovskite crystal growth without experiencing the intermediate phase formation and would evaporate from the perovskite after annealing.Additionally,a gradient perovskite structure was achieved using this technique,which impressively enhanced the performance of the perovskite films.A high power conversion efficiency(PCE)of 20.03%was achieved under the optimal amount of EACl,and the resultant efficient device could retain over 89%of the original PCE after aging for 1000 h at room temperature.This novel technique leads to a facile fabrication of highquality and less-defect perovskite thin films for competent and stable devices.展开更多
Hybrid organic-inorganic halide perovskite material has been considered as a potential candidate for various optoelectronic applications. However, their high sensitivity to the environment hampers the actual applicati...Hybrid organic-inorganic halide perovskite material has been considered as a potential candidate for various optoelectronic applications. However, their high sensitivity to the environment hampers the actual application.Hence the technology replacing the organic part of the hybrid solar cells needs to be developed. Herein, we fabricated fullyinorganic carbon-based perovskite CsPbBr_3 solar cells via a sequential deposition method with a power conversion efficiency of 2.53% and long-time stability over 20 d under ambient air conditions without any encapsulation. An evolution process from tetragonal CsPb_2Br_5 to CsPb_2Br_5-CsPbBr_3 composites to quasi-cubic CsPbBr_3 was found, which was investigated by scanning electron microscopy, X-ray diffraction spectra, UV-vis absorption spectra and Fourier transform infrared spectroscopy. Detailed evolution process was studied to learn more information about the formation process before10 min. Our results are helpful to the development of inorganic perovskite solar cells and the CsPb_2Br_5 based optoelectronic devices.展开更多
基金supported by the National Basic Research Program of China (2016YFA0202400 and 2015CB932200)the National Natural Science Foundation of China (21403247)+2 种基金the External Cooperation Program of BIC, Distinguished Youth Foundation of Anhui Province (1708085J09)Chinese Academy of Sciences (GJHZ1607)STS project of Chinese Academy of Sciences (KFJ-SW-STS-152)
文摘The anti-polar solvent technique is an effec- tive way to improve the film quality in a perovskite solar cell. In this work, we reveal the reason why chloroben- zene （CBZ） plays an important role in controlling the crystallization process. By investigating the formation of intermediate phases in the precursor solution, we observed that the CH3NH3I （MAI）-PbI2-dimethylformamide （DMF） or MAI-PbI2-dimethylsulphoxide （DMSO） adducts have not yet formed until washed with non-polar solvent. The accelerated formation of intermediate phase yields high crystalline perovskite layers. Rapid solvent evaporation and retarded perovskite crystallization in one-step method are efficient to obtain high-quality perovskite films. Conse- quently, MAI-PbI2-DMSO intermediate shows neat rod-like structure with high crystallinity, which eventually transforms extremely dense and uniform perovskite films.
基金supported by the National Key Research and Development Program of China (2016YFA0202400)the 111 project (B16016)the National Natural Science Foundation of China (51572080, 51702096, and U1705256)
文摘Researchers working in the field of photovoltaic are exploring novel materials for the efficient solar energy conversion.The prime objective of the discovery of every novel photovoltaic material is to achieve more energy yield with easy fabrication process and less production cost features.Perovskite solar cells (PSCs)delivering the highest efficiency in the passing years with different stoichiometry and fabrication modification have made this technology a potent candidate for future energy conversion materials.Till now,many studies have shown that the quality of active layer morphology,to a great extent,determines the performance of PSCs.The current and potential techniques of solvent engineering for good active layer morphology are mainly debated using primary solvent,co-solvent (Lewis acid-base adduct approach)and solvent additives.In this review,the dynamics of numerously reported solvents on the morphological characteristics of PSCs active layer are discussed in detail.The intention is to get a clear understanding of solvent engineering induced modifications on active layer morphology in PSC devices via different crystallization routes.At last,an attempt is made to draw a framework based on different solvent coordination properties to make it easy for screening the potent solvent contender for desired PSCs precursor for a better and feasible device.
基金This work was supported by the National Key Research and Development Program of China(2017YFE0133800)the Distinguished Youth Foundation of Anhui Province(1708085J09).
文摘Formamidinium lead halide(α-FAPbI3)with a broad light absorption spectrum,has recently received considerable attention in optoelectronic applications.However,the FAI-PbI2-DMSO(DMSO:dimethyl sulfoxide)intermediate anisotropic fibers readily form a non-perovskite phase(δ-FAPbI3)and uncontrolled excess PbI2,which hinders the further increase in the efficiencies of solar cells.Caculations indicate that iodine defects in polycrystalline films would enlarge the perovskite tolerance factor and result in the formation of iodide Frenkel defects.Herein,we introduce a post-treatment technique to heal the as-prepared FAPbI3 thin layer and restrain the notoriousδ-FAPbI3 through vacancy filling.Furthermore,a new intermediate phase of FAI-PbI2-DMSO-FACl led to a high-quality perovskite layer with an enlarged average grain size that exceeded 2μm.Consequently,the power conversion efficiencies of FAPbI3 solar cells were significantly enhanced due to the high crystallity of the pureα-phase perovskite.Therefore,this method can be used to obtain high pure-black perovskite films and efficient solar cells.
基金support from the National Key Research and Development Program of China (2016YFA0202401)the 111 Project (B16016)+2 种基金the National Natural Science Foundation of China (51702096 and U1705256)the Fundamental Research Funds for the Central Universities (2018ZD07)Metatest Scan Pro Laser Scanning System
文摘To date, extensive research has been carried out,with considerable success, on the development of highperformance perovskite solar cells(PSCs). Owing to its wide absorption range and remarkable thermal stability, the mixedcation perovskite FAxMA1-xPbI3(formamidinium/methylammonium lead iodide) promises high performance. However, the ratio of the mixed cations in the perovskite film has proved difficult to control with precursor solution. In addition, the FAxMA1-xPbI3 films contain a high percentage of MA+and suffer from serious phase separation and high trap states, resulting in inferior photovoltaic performance. In this study, to suppress phase separation, a post-processing method was developed to partially nucleate before annealing, by treating the as-prepared intermediate phase FAI-Pb I2-DMSO(DMSO: dimethylsulfoxide) with mixed FAI/MAI solution. It was found that in the final perovskite, FA0.92MA0.08 PbI3, defects were substantially reduced because the analogous molecular structure initiated ion exchange in the post-processed thin perovskite films, which advanced partial nucleation. As a result, the increased light harvesting and reduced trap states contributed to the enhancement of open-circuit voltage and short-circuit current. The PSCs produced by the post-processing method presented reliable reproducibility, with a maximum power conversion efficiency of 20.80% and a degradation of ~30% for 80 days in standard atmospheric conditions.
基金supported by the National Key R&D Program of China(2019YFB1503202)the 111 Project(B16016)+1 种基金the National Natural Science Foundation of China(51702096,U1705256 and 61904053)the Fundamental Research Funds for the Central Universities(2019MS026,2019MS027 and 2020MS080)。
文摘The quality of the perovskite light absorption layer plays a dynamic role in the photovoltaic properties of solar cells.The existing methods to prepare methylammonium lead iodide(MAPbI3)films render substantial structural defect density,particularly at the grain boundaries and film surface,constituting a challenge that hinders the further optoelectronic enhancement of perovskite solar cells.Herein,a unique approach was introduced:using a simple ethylammonium chloride(EACl)additive in perovskite precursor mixture to produce high-quality MAPbI3 thin films.The results indicated that EACl could encourage perovskite crystal growth without experiencing the intermediate phase formation and would evaporate from the perovskite after annealing.Additionally,a gradient perovskite structure was achieved using this technique,which impressively enhanced the performance of the perovskite films.A high power conversion efficiency(PCE)of 20.03%was achieved under the optimal amount of EACl,and the resultant efficient device could retain over 89%of the original PCE after aging for 1000 h at room temperature.This novel technique leads to a facile fabrication of highquality and less-defect perovskite thin films for competent and stable devices.
基金supported by the National Basic Research Program of China (2016YFA0202400 and 2015CB932200)the National Natural Science Foundation of China (21403247)+2 种基金Distinguished Youth Foundation of Anhui Province (1708085J09)the Fundamental Research Funds for the Central Universities (2017XS079)the Major/Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology (2016FXZY003)
文摘Hybrid organic-inorganic halide perovskite material has been considered as a potential candidate for various optoelectronic applications. However, their high sensitivity to the environment hampers the actual application.Hence the technology replacing the organic part of the hybrid solar cells needs to be developed. Herein, we fabricated fullyinorganic carbon-based perovskite CsPbBr_3 solar cells via a sequential deposition method with a power conversion efficiency of 2.53% and long-time stability over 20 d under ambient air conditions without any encapsulation. An evolution process from tetragonal CsPb_2Br_5 to CsPb_2Br_5-CsPbBr_3 composites to quasi-cubic CsPbBr_3 was found, which was investigated by scanning electron microscopy, X-ray diffraction spectra, UV-vis absorption spectra and Fourier transform infrared spectroscopy. Detailed evolution process was studied to learn more information about the formation process before10 min. Our results are helpful to the development of inorganic perovskite solar cells and the CsPb_2Br_5 based optoelectronic devices.
