Although perovskite solar cells (PSCs) have achieved the highest power conversion efficiency (PCE) of 25.2% in a very short period of development, they suffer from poor stability because the organic–inorganic hybrid perovskite materials are easily decomposed under the attacks of oxygen, moisture, heat and ultraviolet light. It is demonstrated that an all inorganic perovskite material of CsPbBr₃ has excellent stability against moisture, oxygen and heat, but it has a slightly wide bandgap of 2.3 eV, which seriously hinders light absorption and leads to poor PCE. Metal ion doping is a good approach to overcome this drawback because it can effectively tune the bandgap, enhance light absorption, suppress trap states and adjust the energy level. Here, we use the CoBr₂ doping route to fabricate high quality and crystallinity CoBr₂ doped CsPbBr₃ film. As a result, a champion device with the CsPb_0.998Co_0.002Br₃ film yields a PCE as high as 8.57%, much higher than that of the pristine CsPbBr₃ one (6.81%). It is found that the lower number of trap defects and higher carrier density of the CsPb_0.998Co_0.002Br₃ film are key reasons for the enhancement because they bring about better charge carrier dynamics and suppressed dark recombination.

中文翻译：

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CoBr2掺杂引起的CsPbBr3平面钙钛矿太阳能电池效率的提高

尽管钙钛矿太阳能电池（PSC）在很短的开发时间内就达到了25.2％的最高功率转换效率（PCE），但由于有机-无机杂化钙钛矿材料很容易在氧气的侵蚀下分解，因此钙钛矿太阳能电池的稳定性很差。水分，热量和紫外线。已经证明，CsPbBr ₃的全无机钙钛矿材料具有优异的抗潮，抗氧和抗热稳定性，但其带隙较宽，为2.3 eV，严重阻碍了光吸收并导致不良的PCE。金属离子掺杂是克服此缺点的好方法，因为它可以有效地调节带隙，增强光吸收，抑制陷阱态并调节能级。在这里，我们使用CoBr ₂掺杂途径以制备高质量和结晶性的CoBr ₂掺杂的CsPbBr ₃薄膜。结果，具有CsPb _0.998 Co _0.002 Br ₃膜的冠军设备产生的PCE高达8.57％，远高于原始CsPbBr ₃ one（6.81％）的PCE 。已经发现，CsPb _0.998 Co _0.002 Br ₃膜的陷阱缺陷数量少和载流子密度高是增强的关键原因，因为它们带来了更好的电荷载流子动力学并抑制了暗重组。