Perovskite layers make the grade Inverted planar perovskite solar cells offer opportunities for a simplified device structure compared with conventional mesoporous titanium oxide interlayers. However, their lower open-circuit voltages result in lower power conversion efficiencies. Using mixed-cation lead mixed-halide perovskite and a solution-processed secondary growth method, Luo et al. created a surface region in the perovskite film that inhibited nonradiative charge-carrier recombination. This kind of solar cell had comparable performance to that of conventional cells. Science, this issue p. 1442 High open-circuit voltages were achieved for planar perovskite solar cells by creating a graded junction. The highest power conversion efficiencies (PCEs) reported for perovskite solar cells (PSCs) with inverted planar structures are still inferior to those of PSCs with regular structures, mainly because of lower open-circuit voltages (Voc). Here we report a strategy to reduce nonradiative recombination for the inverted devices, based on a simple solution-processed secondary growth technique. This approach produces a wider bandgap top layer and a more n-type perovskite film, which mitigates nonradiative recombination, leading to an increase in Voc by up to 100 millivolts. We achieved a high Voc of 1.21 volts without sacrificing photocurrent, corresponding to a voltage deficit of 0.41 volts at a bandgap of 1.62 electron volts. This improvement led to a stabilized power output approaching 21% at the maximum power point.

中文翻译：

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用于反向平面异质结钙钛矿太阳能电池的增强光电压

与传统的介孔氧化钛夹层相比，钙钛矿层使等级 倒置平面钙钛矿太阳能电池为简化器件结构提供了机会。然而，它们较低的开路电压会导致较低的功率转换效率。使用混合阳离子铅混合卤化物钙钛矿和溶液处理的二次生长方法，Luo 等人。在钙钛矿薄膜中创建了一个表面区域，抑制了非辐射电荷载流子复合。这种太阳能电池具有与传统电池相当的性能。科学，这个问题 p。1442 通过创建渐变结，平面钙钛矿太阳能电池实现了高开路电压。具有倒置平面结构的钙钛矿太阳能电池 (PSC) 的最高功率转换效率 (PCE) 仍低于具有规则结构的 PSC，主要是因为开路电压 (Voc) 较低。在这里，我们报告了一种基于简单的溶液处理二次生长技术来减少倒置器件非辐射复合的策略。这种方法产生了更宽的带隙顶层和更多 n 型钙钛矿薄膜，从而减轻了非辐射复合，导致 Voc 增加高达 100 毫伏。我们在不牺牲光电流的情况下实现了 1.21 伏的高 Voc，对应于 1.62 电子伏的带隙下 0.41 伏的电压不足。这种改进导致在最大功率点时稳定的功率输出接近 21%。