Role of GeI2 and SnF2 additives for SnGe perovskite solar cells
Role of GeI2 and SnF2 additives for SnGe perovskite solar cells
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DOI：
10.1016/j.nanoen.2019.01.026
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发表时间：
2019-04-01
期刊：
影响因子：
17.6
通讯作者：
Hayase, Shuzi
中科院分区：
文献类型：
--
作者：
Ng, Chi Huey;Nishimura, Kohei;Hayase, Shuzi
陷阱态在钙钛矿附近或异质界面的分布是导致载流子动力学劣势和低光伏性能的主要原因。在这项工作中，热刺激电流(TSC)被用来揭示锗(Ge)添加在钝化和还原陷阱态中的影响，从而改善其载流子动力学。在FA(0.75)MA(0.25)Sn(1-x)Ge(X)I(3)(FMSGI(5))骨架中加入5mol%的Ge，使陷阱密度从10(15)-10(17)cm(-3)(不含Ge)显著降低到10(8)-10(14)cm(-3)，从而获得更长的电荷扩散长度(接近1微米)和更长的寿命；同时还具有良好的电荷迁移率和7.9%的效率。有趣的是，FMSGI(5)钙钛矿的陷阱密度分布与MAPbI(3)钙钛矿的没有区别，并且具有长达1微米的电荷扩散长度。另一个要强调的重要信息是SnF2对Sn2+空位的抑制作用。这项研究提供了对陷阱环境的深刻直观，为设计高性能无铅钙钛矿太阳能电池释放了机会。
The distribution of trap states within perovskite vicinity or hetero-interfaces is the prime attribution towards carrier dynamics inferiority and low photovoltaic performances. In this work, thermally stimulated current (TSC) is performed to unravel the impact of germanium (Ge) addition in passivating and reducing trap states; consequently, to improve its carrier dynamics. The addition of 5 mol% germanium into the FA(0.75)MA(0.25)Sn(1-x)Ge(x)I(3) (FMSGI(5)) framework strikingly suppresses the trap density from 10(15) - 10(17) cm(-3) (without Ge) to 10(8) -10(14) cm(-3), thereby renders longer charge diffusion length (similar to 1 mu m) and lifetime; coupled with excellent charge mobility and efficiency of 7.9%. Interestingly, the FMSGI(5) perovskite exhibits indistinguishable trap densities profile from that of MAPbI(3) perovskite and exhibits a long charge diffusion length of 1 mu m. Another important information to be highlighted in this paper is the advantage of SnF2 to subside the vacancy of Sn2+. This study provides deep intuitive on trap landscape, which unlocks opportunities for the designation of high performance lead-free perovskite solar cells.