Nickel oxide (NiO_x) has exhibited great potential as an inorganic hole transport layer (HTL) in perovskite solar cells (PSCs) due to its wide optical bandgap and superior stability. In this study, we have modulated the Ni²⁺ vacancies in NiO_x film by controlling deposition temperature in a hot-casting process, resulting the change of coordination structure and charge state of NiO_x. Moreover, the change of the HOMO level of NiO_x makes it more compatible with perovskite to decrease energy losses and enhance hole carrier injection efficiency. Besides, the defect modulation in the electronic structure of NiO_x is beneficial for increasing the electrical conductivity and mobility, which are considered to achieve the balance of charge carrier transport and avoid charge accumulation at the interface between perovskite and HTL effectively. Both experimental analyses and theoretical calculations reveal the increase of nickel vacancy defects change the electronic structure of NiO_x by increasing the ratio of Ni³⁺/Ni²⁺ and improving the p-type characteristics. Accordingly, an optimal deposition temperature at 120°C enabled a 36.24% improvement in the power conversion efficiency compared to that deposited at room temperature (25°C). Therefore, this work provides a facile method to manipulate the electronic structure of NiO_x to improve the charge carrier transport and photovoltaic performance of related PSCs.

氧化镍（NiO _x）具有宽的光学带隙和出色的稳定性，因此在钙钛矿型太阳能电池（PSC）中作为无机空穴传输层（HTL）具有巨大的潜力。在这项研究中，我们通过控制热浇铸过程中的沉积温度来调制NiO _x膜中的Ni ²⁺空位，从而改变了NiO _x的配位结构和电荷状态。而且，NiO _x的HOMO能级的变化使其与钙钛矿更加相容，从而减少了能量损失并提高了空穴载流子注入效率。此外，NiO _x电子结构中的缺陷调制有利于提高电导率和迁移率，这被认为可以实现电荷载流子传输的平衡并有效避免钙钛矿与HTL之间界面处的电荷积聚。实验分析和理论计算均表明，通过增加Ni ³⁺ / Ni ²⁺的比例和改善p型特性，镍空位缺陷的增加改变了NiO _x的电子结构。因此，最佳沉积温度为120°C可使功率转换效率比在室温下沉积的功率转换效率高36.24％（25°C）。因此，这项工作提供了一种简便的方法来操纵NiO _x的电子结构，以改善相关PSC的电荷载流子传输和光伏性能。