摘要
An inverted planar heterojunction perovskite solar cell （PSC） is one of the most competitive photovoltaic devices exhibiting a high power conversion efficiency （PCE） and nearly free hysteresis in the voltage-current output. However, the band alignment between the transport materials and the perovskite absorber has not been optimized, resulting in a lower open-circuit voltage （Voc） than that of regular PSCs. To address this issue, we tune the band alignment in perovskite photovoltaic architecture by introducing bilayer structured transport materials, e.g., the hole transport material poly（ethylenedioxythiophene）：poly（styrene sulfonate） （PEDOT：PSS）/V2Os. In this study, solution processed inorganic V2Ox interlayer is incorporated into PEDOT：PSS for achieving improved film surface properties as well as optical and electrical properties. For example, the work function （WF） was changed from 5.1 to 5.4 eV. A remarkably high PCE of 17.5% with nearly free hysteresis and a stabilized efficiency of 17.1% have been achieved. Electronic impedance spectra （EIS） demonstrate a significant increase in the recombination resistance after introducing the interlayer, associated with the high Voc output value of 1.05 V. Transient photocurrent and photovoltage measurements indicate that a comparable charge transport process and an inhibited recombination process occur in the PSC with the introduction of the V20x interlayer.
An inverted planar heterojunction perovskite solar cell （PSC） is one of the most competitive photovoltaic devices exhibiting a high power conversion efficiency （PCE） and nearly free hysteresis in the voltage-current output. However, the band alignment between the transport materials and the perovskite absorber has not been optimized, resulting in a lower open-circuit voltage （Voc） than that of regular PSCs. To address this issue, we tune the band alignment in perovskite photovoltaic architecture by introducing bilayer structured transport materials, e.g., the hole transport material poly（ethylenedioxythiophene）：poly（styrene sulfonate） （PEDOT：PSS）/V2Os. In this study, solution processed inorganic V2Ox interlayer is incorporated into PEDOT：PSS for achieving improved film surface properties as well as optical and electrical properties. For example, the work function （WF） was changed from 5.1 to 5.4 eV. A remarkably high PCE of 17.5% with nearly free hysteresis and a stabilized efficiency of 17.1% have been achieved. Electronic impedance spectra （EIS） demonstrate a significant increase in the recombination resistance after introducing the interlayer, associated with the high Voc output value of 1.05 V. Transient photocurrent and photovoltage measurements indicate that a comparable charge transport process and an inhibited recombination process occur in the PSC with the introduction of the V20x interlayer.
基金
The authors are grateful to Dr. Xinchen Li of Zolix Instruments Co., Ltd. for transient measurements and Prof. Jinglin Xie for XPS measurements. This work was supported by the National Basic Research Program of China （No. 2011CB933303） and the National Natural Science Foundation of China （NSFC） （Nos. 21321001 and 21371012）. This work was also supported by the ＂Thousand Youth Talents Plan＂, China.
