The improvement of the quality of the hole transporting layer (HTL) plays a key role in the fabrication of highly efficient and stable perovskite solar cells (PSCs). Here, we used rubrene as a surface treatment agent on top of a spiro HTL. We found that rubrene can cover the pinholes of the spiro layer and provide an excellent contact layer for planar PSCs. Based on this modification, mobile gold ions from the metal electrode are prevented from diffusing through the HTL hindering the degradation of PSCs. The optimized device shows a maximum power conversion efficiency (PCE) of 19.87% and a 79% fill factor (FF), which are higher than the 17.98% PCE and 72% FF of the reference device. In addition, the device after modification demonstrates better stability after 100 h under continuous light illumination retaining 97% of its initial performance compared with 65% of the reference device.

中文翻译：

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高效钙钛矿型太阳能电池的空穴传输层的表面改性，具有增强的填充系数和稳定性†

空穴传输层（HTL）质量的提高在高效，稳定的钙钛矿太阳能电池（PSC）的制造中起着关键作用。在这里，我们将红荧烯用作螺旋HTL顶部的表面处理剂。我们发现，红荧烯可以覆盖螺旋层的针孔，并为平面PSC提供出色的接触层。基于该修改，防止了来自金属电极的可移动金离子通过HTL扩散，从而阻碍了PSC的降解。经过优化的器件的最大功率转换效率（PCE）为19.87％，填充因子（FF）为79％，高于参考器件的17.98％PCE和72％FF。此外，