Inorganic cesium metal halide perovskites have gained research interest as absorbers in perovskite solar cells due to their superior thermal stability.Among these,CsPbI2Br,with a narrower band gap than CsPbBr3 and a b...Inorganic cesium metal halide perovskites have gained research interest as absorbers in perovskite solar cells due to their superior thermal stability.Among these,CsPbI2Br,with a narrower band gap than CsPbBr3 and a better phase stability than CsPbI3,has received tremendous interest of the researchers.However,CsPbI2 Br takes adverse phase transfer easily with an exposure to the water vapor in ambient air which not only brings inconvenience for researches but also puts forward very high requirement for encapsulation.Herein,a dense and uniform film is obtained by incorporating hydrophobic CH3NH3Cl(MACl)into the precursor solution.Being attributed to a good passivation effect,the defect density is decreased from3.12×1016 to 1.49×1016 cm-3 and the average photoluminescence lifetime is increased from 8.84 to 20.6 ns.The photovoltaic device achieves a high open-circuit voltage of 1.22 V based on optimized MACl-doped film and accordingly a higher power conversion efficiency(PCE) of 12.9% which is 21.7% higher than the pristine CsPbI2Br device with PCE of 10.6%.In addition,the ambient stability of MACl-doped device has been enhanced,which is greatly attributed to the hydrophobic properties of MACl.This work provides a clue to improve ambient stability of inorganic perovskite solar cells and inspires toward further development of this material.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51672094,51861145404 and 51822203)the China Postdoctoral Science Foundation(No.2016M602286)+2 种基金the Self-determined and Innovative Research Funds of HUST(No.2016JCTD111)Shenzhen Science and Technology Innovation Committee(No.JCYJ20170307165905513)the Natural Science Foundation of Guangdong Province(No.2017A030313342).
文摘Inorganic cesium metal halide perovskites have gained research interest as absorbers in perovskite solar cells due to their superior thermal stability.Among these,CsPbI2Br,with a narrower band gap than CsPbBr3 and a better phase stability than CsPbI3,has received tremendous interest of the researchers.However,CsPbI2 Br takes adverse phase transfer easily with an exposure to the water vapor in ambient air which not only brings inconvenience for researches but also puts forward very high requirement for encapsulation.Herein,a dense and uniform film is obtained by incorporating hydrophobic CH3NH3Cl(MACl)into the precursor solution.Being attributed to a good passivation effect,the defect density is decreased from3.12×1016 to 1.49×1016 cm-3 and the average photoluminescence lifetime is increased from 8.84 to 20.6 ns.The photovoltaic device achieves a high open-circuit voltage of 1.22 V based on optimized MACl-doped film and accordingly a higher power conversion efficiency(PCE) of 12.9% which is 21.7% higher than the pristine CsPbI2Br device with PCE of 10.6%.In addition,the ambient stability of MACl-doped device has been enhanced,which is greatly attributed to the hydrophobic properties of MACl.This work provides a clue to improve ambient stability of inorganic perovskite solar cells and inspires toward further development of this material.
