Unravelling the origin of the photocarrier dynamics of fullerene-derivative passivation of SnO2 electron transporters in perovskite solar cells
Unravelling the origin of the photocarrier dynamics of fullerene-derivative passivation of SnO2 electron transporters in perovskite solar cells
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DOI：
10.1039/d0ta08752a
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发表时间：
2020-11-28
影响因子：
11.9
通讯作者：
Chen, Chun-Wei
中科院分区：
文献类型：
--
作者：
Huang, Shao-Ku;Wang, Ying-Chiao;Chen, Chun-Wei
富勒烯钝化的SnO 2电子传输层（ETL）为钙钛矿太阳能电池（PSC）的功率转换效率（PCE）的持续提升提供了一条途径。然而，在PSC组成的富勒烯钝化的SnO 2 ETL的光载流子动力学的详细了解仍然缺乏。在这里，我们使用超快泵-探测瞬态吸收光谱来分析PSC中富勒烯修饰的SnO 2 ETL中相应的光生载流子动力学。C-60吡咯烷三酸（CPTA）修饰的SnO 2 ETL和6，6-苯基C-61-丁酸甲酯（PC61 BM）修饰的SnO 2 ETL都具有与钙钛矿有利的能带边缘对准，与未修饰的SnO 2 ETL相比，将这两种富勒烯引入SnO 2基PSC后，导致电子注入速率增强。此外，结合化学测量和密度泛函理论模拟结果，证实了SnO 2表面与CPTA的羧酸之间的界面化学键是定制的，从而建立了界面偶极子。由于界面偶极子的存在，CPTA富勒烯的化学吸附在CPTA钝化的SnO 2/钙钛矿界面和钙钛矿内部都起到复合抑制剂的作用。相比之下，PC61 BM富勒烯在SnO 2 ETL上的物理吸附在SnO 2/钙钛矿界面和钙钛矿内部都表现出相对高的复合率。因此，基于SnO 2/CPTA ETL的PSC产生超过19%的PCE，这上级于使用PC 61 BM作为钝化剂的参考PSC（
Fullerene-passivated SnO2 electron transport layers (ETLs) offer a route for a continuous boost in the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs). However, a detailed understanding on the photocarrier dynamics in PSCs consisting of fullerene-passivated SnO2 ETLs is still lacking. Here, we use ultrafast pump-probe transient absorption spectroscopy to analyze the corresponding photocarrier dynamics across fullerene-modified SnO2 ETLs in PSCs. Both the C-60 pyrrolidine tris-acid (CPTA)-modified SnO2 ETL and 6,6-phenyl C-61-butyric acid methyl ester (PC61BM)-modified SnO2 ETL which have a favorable energy band edge alignment to perovskites, result in an enhanced electron injection rate after introducing these two fullerenes into SnO2-based PSCs compared to the SnO2 ETL without modification. Moreover, combining chemical measurements and density functional theory simulation results, it is confirmed that the interfacial chemical bond is tailored between the SnO2 surface and carboxylic acids of CPTA, thus establishing interface dipoles. Due to the existence of interface dipoles, the chemisorption of the CPTA fullerene functions as a recombination suppressor both at the CPTA-passivated SnO2/perovskite interface and inside perovskites. By contrast, the physisorption of the PC61BM fullerene on the SnO2 ETL exhibits relatively high recombination rates both at the SnO2/perovskite interface and inside perovskites. Therefore, the PSC based on the SnO2/CPTA ETL yields a PCE of more than 19%, which is superior to that of the reference PSC using PC61BM as a passivator (