Organic-inorganic hybrid halide perovskite materials have been a suitable active layer in solar cells due to the extraordinary photonic and electronic properties.Perovskite solar cells(PSCs),no matter conventional structure or inverted structure,contain several key interfaces,including electrode/electron transport materials(ETM) interface,ETM/perovskite interface,perovskite/hole transport materials(HTM) interface,HTM/electrode interface.The interface is vital to the overall performance of the devices,since the exciton formation,dissociation,and recombination are directly related to the interface.Moreover,the degradation of devices is also highly sensitive to the interface.As a result,the deep understanding of the interfadal charge transfer and corresponding interfadal engineering is extremely important to achieve high-performance and high-stability PSCs.This review mainly focuses on the recent progress of interfacial engineering in PSCs,including conventional structured PSCs,PSCs employing carbon counter electrode,and inverted structured PSCs.
Here,the interfacial synergism of discontinuous spot shaped SnO_2 and TiO_2 mesoporous nanocomposite as electron transfer layer（ETL） underlayer is presented in highly efficient mesoscopic perovskite solar cells（M-PSCs）. Based on this new strategy,strong charge recombination observed in previous SnO_2-based ETLs is suppressed to a great extent as the pathways of charge recombination and energy loss are blocked effectively. Meanwhile,the internal series resistance of entire M-PSC is decreased remarkably. The new ETL is more kinetically favorable to electron transfer and thus results in significant photovoltaic improvement and alleviated hysteresis effect of M-PSCs.
Herein, we for the first time doped Nb^5+into the low-temperature(<100°C) SnO2sol-gel route to tailor the electrical property of SnO2 layers and the band alignment between SnO2 and the normally used mixed perovskites. The results revealed that proper Nb5+doping increased the conductivity of the SnO2 electron transport layer(ETL), and the conduction band(CB) level of the SnO2 ETL was shifted down to approach the CB level of perovskites, which facilitated the electron injection from perovskite to SnO2, accelerated the charge transport, and reduced the non-radiative recombination, leading to improved power conversion efficiency from18.06% to 19.38%. The Nb^5+doping process provided an efficient route for fabricating high-efficiency perovskite solar cells(PSCs) at a temperature lower than 100°C, and promoted the commercialization progress of PSCs.
Jing LiuNan LiQingshun DongJiangwei LiChao QinLiduo Wang
