Although the efficiency of perovskite solar cells is over 25%, there is still a big difference between the open-circuit voltage and its theoretical value, which is ascribed to defects in the perovskite films. Here, 4-iodo-1H-imidazole is introduced into a perovskite precursor to prevent defect formation in final films. The open-circuit voltage is significantly elevated to 1.209 V from 1.085 V. 4-Iodo-1H-imidazole, as a kind of small organic molecule, can not only reduce pin-holes in perovskite films by participating in the growth of perovskite crystals, but also suppress the generation of defects, resulting in decreased nonradiative recombination. Finally, the device efficiency becomes 21.68%, which is increased by 20% in comparison with that of the control device (17.87%).

中文翻译：

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4-Iodo-1H-imidazole 将钙钛矿太阳能电池的开路电压显着提高至 1.2 V

尽管钙钛矿太阳能电池的效率超过 25%，但开路电压与其理论值之间仍有很大差异，这是由于钙钛矿薄膜存在缺陷所致。在这里，将 4-iodo-1 H-咪唑引入钙钛矿前体中，以防止最终薄膜中形成缺陷。开路电压从1.085 V显着升高到1.209 V。4-Iodo-1 H-咪唑作为一种有机小分子，不仅可以通过参与钙钛矿晶体的生长来减少钙钛矿薄膜中的针孔，但也抑制缺陷的产生，导致非辐射复合减少。最后，设备效率变为21.68%，与控制设备的效率（17.87%）相比提高了20%。