报告题目：Interface Engineering in Planar Perovskite Solar Cells with Fullerene Derivatives

报告人：陶晨 博士（意大利Italy Institute of Technology IIT研究所）

报告时间：2017年6月6日下午2：30

报告地点：物理学院新楼多功能厅

报告摘要:

The past 8 years have seen dramatic increase in the performance of perovskite solar cells (PSCs) with certified efficiencies over 20% that are approaching the level of Si solar cells. Although the standard meso-structured PSCs yield higher efficiencies as well as less hysteresis, the high temperature involved meso-structured TiO2 layer increases the fabrication cost and makes them not suitable on flexible plastic substrates. Therefore, standard PSCs with a planar structure are highly desired. However, it has been shown that the notorious hysteretic behavior prevents a correct evaluation of their potential. Hence, it is required to modify the interface between perovskite and the electron transport layer, which has been shown to be the main origin of hysteresis.

To address these issues, we will describe efficient planar methylammonium lead iodide (CH3NH3PbI3) PSCs fabricated with two kinds of electron transport layer using fullerene derivatives, TiOx/[6,6]-phenyl-C61-butyric acid methyl ester (60-PCBM) and TiO2/crosslinked [6,6]-phenyl-C61-butyric styryl dendron ester (C-PCBSD) in conjunction with 2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenylamine)-9-9’-spirobifluorene (spiro-MeOTAD) as the hole transport layer. The optimised TiOx/60-PCBM with evaporation-solution hybrid processed CH3NH3PbI3 absorbing layers yields 17.6% stabilized efficiencies, while the TiO2/c-PCBSD with all solution-processed CH3NH3PbI3 achieves efficiencies close to 19%. They both significantly outperform their corresponding TiO2-only references with less hysteresis. Perovskite deposited on fullerene derivatives presents larger-size grains with fewer boundaries. Photo-induced transient measurements show that the more efficient charge extraction and longer charge carrier lifetime in both 60-PCBM and C-PCBSD devices accounting for the higher power conversion efficiencies compared to the TiO2-only references. Our results indicate that fullerene derivatives are a good candidate to be an electron transport layer in planar PSCs with a standard structure. In particularly, the solution processed, robust TiO2/C-PCBSD is well suited to high throughput, low cost all-solution processing PSCs.

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