The lead‐free double perovskite, Cs₂AgBiBr₆, has received keen attention as photovoltaic absorber with nontoxicity and highly stabilities. However, the large bandgap (2.1 eV) and low optical absorption property of Cs₂AgBiBr₆ have limited its power conversion efficiency (PCE) in perovskite solar cells (PSCs) to low values around 2% due to the lack in short‐circuit current density (J_sc). Herein, Cs₂AgBiBr₆ perovskite is combined with a photoactive zinc chlorophyll derivative (Zn‐Chl) as a hole‐transporting layer (HTL) that is capable of sensitizing the perovskite absorber. The Zn‐Chl‐sensitized Cs₂AgBiBr₆ device exhibits a PCE up to 2.79%, the highest value for double perovskite‐based solar cells to date, with a J_sc of 3.83 mA cm⁻², which is 22–27% higher than that of the devices with conventional nonphotoactive HTLs such as 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐OMeTAD), poly(3‐hexylthiophene) (P3HT), and poly(triarylamine) (PTAA). Through photophysical investigation, it is found that the Zn‐Chl not only plays the role of an HTL but also the role of a photoactive layer in the PSC devices. Moreover, the Zn‐Chl‐based device shows a much higher extinction coefficient than those based on Spiro‐OMeTAD, P3HT, and PTAA. This work demonstrates promise toward the realization and application of environmentally friendly solar cells.

中文翻译：

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光敏锌叶绿素空穴转运体敏化的无铅Cs2AgBiBr6钙钛矿太阳能电池

无铅双钙钛矿Cs ₂ AgBiBr ₆作为无毒，高稳定性的光伏吸收剂受到了广泛关注。但是，由于缺乏短路电流，Cs ₂ AgBiBr ₆的大带隙（2.1 eV）和低的光吸收特性将其在钙钛矿太阳能电池（PSC）中的功率转换效率（PCE）限制在2％左右的低值密度（J _sc）。在此，将Cs ₂ AgBiBr ₆钙钛矿与光敏性叶绿素锌衍生物（Zn-Chl）结合在一起，作为能够使钙钛矿吸收剂增感的空穴传输层（HTL）。Zn-Chl敏化的Cs ₂ AgBiBr ₆该设备的PCE高达2.79％，是迄今为止钙钛矿型双倍太阳能电池的最高值，J _sc为3.83 mA cm ^-2，比具有常规非光敏性HTL的设备高出22–27％。如2,2'，7,7'-四（N，N-二- p-甲氧基苯胺）-9,9'-螺二芴（Spiro-OMeTAD），聚（3-己基噻吩）（P3HT）和聚（三芳基胺）（PTAA）。通过光物理研究，发现Zn-Chl不仅起着HTL的作用，而且还起着PSC器件中光敏层的作用。此外，基于Zn-Chl的器件的消光系数比基于Spiro-OMeTAD，P3HT和PTAA的器件高得多。这项工作表明了对实现和应用环保太阳能电池的希望。