Doping of bis(trifluoromethane)sulfonimide (LiTFSI) and 4-tert-butylpyridine (TBP) in 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD) is currently considered irreplaceable for fabricating high-performance perovskite solar cells (PSCs). However, the stability of Spiro-OMeTAD was demonstrated to be seriously limited by the Li⁺ diffusion of LiTFSI and the volatilization of TBP. Herein, we report a strategy of doping with an organic molten salt, cyclohexylamine trifluoroacetic acid (CYTFA), to stabilize doped Spiro-OMeTAD for high-performance PSCs. We found that Li⁺ diffusion and TBP volatilization were effectively suppressed through strong interactions of dissociated CY⁺ and TFA⁻ acting on TBP and Li⁺. Moreover, CYTFA-doped Spiro-OMeTAD exhibits an order of magnitude increase in hole mobility and matched energy levels with perovskites. As a result, a solar cell with a power conversion efficiency of 25.80% was achieved, maintaining 96% and 80% of the initial efficiency for 500 hours at 55 °C and 55% humidity and for 470 hours at the maximum power point, respectively.

中文翻译：

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用有机熔盐稳定掺杂 Spiro-OMeTAD，用于高效稳定的钙钛矿太阳能电池


双（三氟甲烷）磺酰亚胺 （LiTFSI） 和 4-叔丁基吡啶 （TBP） 在 2,2′，7,7′-四（N，N-二-对-甲氧基苯胺）-9,9′-螺芴 （Spiro-OMeTAD） 中的掺杂目前被认为不可替代用于制造高性能钙钛矿太阳能电池 （PSC）。然而，Spiro-OMeTAD 的稳定性被证明受到 LiTFSI 的 Li⁺ 扩散和 TBP 挥发的严重限制。在此，我们报道了一种用有机熔盐环己胺三氟乙酸 （CYTFA） 掺杂的策略，以稳定掺杂的 Spiro-OMeTAD 用于高性能 PSC。我们发现 Li⁺ 扩散和 TBP 挥发通过作用于 TBP 和 Li⁺ 的解离 CY⁺ 和 TFA⁻ 的强烈相互作用被有效抑制。此外，掺杂 CYTFA 的 Spiro-OMeTAD 的空穴迁移率和与钙钛矿相匹配的能级增加了一个数量级。结果，实现了功率转换效率为 25.80% 的太阳能电池，在 55 °C 和 55% 湿度下分别保持 96% 和 80% 的初始效率 500 小时，在最大功率点下保持 470 小时。