Organic small molecule material, spiro-OMeTAD, is widely used in perovskite solar cells as the hole transport material due to its desirable properties, such as suitable highest occupied molecular orbital energy levels, high solubility and good film forming ability. However, the aggregation and hydrolysis of the common additive, Li-TFSI, in the spiro-OMeTAD, lead to the existence of voids/pinholes in the hole transport layer, which limits further improvement of perovskite solar cell efficiency. Here, we develop a low-cost and easy-fabrication technique to substantially reduce the undesired voids in hole transport layer by modifying it with commercially available PbI₂. The strong interaction between the PbI₂ and the TBP retards the evaporation of TBP, which hinders the agglomeration of Li-TFSI and generation of voids in the HTL. Consequently, the HTL shows a dramatically improved mobility and efficiency of charge carrier extraction, leading to a better response to steady-state condition with less than 1s for the corresponding photovoltaic device (where the control device shows more than 26s). A champion power conversion efficiency of over 20% is obtained from PbI₂ added devices by optimizing its adding amount. This work provides a facile and effective strategy to improve the performance of the hole transport materials and perovskite solar cells.

有机小分子材料spiro-OMeTAD由于其理想的特性（例如合适的最高占据分子轨道能级，高溶解度和良好的成膜能力）而广泛用作钙钛矿太阳能电池中的空穴传输材料。然而，在螺-OMeTAD中，常见添加剂Li-TFSI的聚集和水解导致在空穴传输层中存在空隙/针孔，这限制了钙钛矿太阳能电池效率的进一步提高。在这里，我们开发了一种低成本且易于制造的技术，通过使用市售PbI ₂对其进行改性，从而大大减少了空穴传输层中的不良空隙。PbI ₂之间的强相互作用TBP阻碍了TBP的蒸发，从而阻碍了Li-TFSI的团聚和HTL中空隙的产生。因此，HTL显示出显着改善的载流子迁移率和电荷载流子提取效率，从而导致对稳态条件的更好响应，对于相应的光伏设备（控制设备显示大于26s），响应时间小于1s。通过优化PbI ₂的添加量，可以获得超过20％的超级功率转换效率。这项工作为提高空穴传输材料和钙钛矿太阳能电池的性能提供了一种简便有效的策略。