钝化剂乙酰水杨酸对钙钛矿太阳能电池性能影响的研究

有机-无机杂化钙钛矿太阳能电池因其优异的光电性能和低廉的制备成本,成为目前光伏领域内的研究热点。然而,钙钛矿薄膜表面和晶界处存在大量缺陷,这易于导致载流子非辐射复合,并进而影响太阳能电池的光电转换效率。本工作通过在两步法制备钙钛矿的铅盐前驱液中引入钝化剂乙酰水杨酸(acetylsalicylic acid, ASA),利用吸收/光致发光光谱、扫描电镜和电学测试等技术手段研究了ASA分子对钙钛矿薄膜质量与器件性能的影响。结果表明:适量的ASA分子可以通过路易斯酸碱相互作用增大钙钛矿晶粒尺寸,并有效降低钙钛矿薄膜的缺陷密度;当ASA的浓度为2.5 mmol/L时,所制得的钙钛矿电池取得了19.83%的最高光电转换效率,明显高于对照器件的转换效率(17.47%)。本工作首次报道了ASA对钙钛矿薄膜缺陷的良好钝化效果,并为提高钙钛矿太阳能电池性能提供了一种简单有效的制备方法。

Effect of Acetylsalicylic Acid Passivator on the Performance of Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells have attracted much attention due to their excellent optoelectronic properties and low preparation cost. However, a large number of defects exist on the surface and grain boundaries of perovskite films, which lead to non-radiative recombination of carriers and affect the photoelectric conversion efficiency of solar cells. In this work, acetylsalicylic acid (ASA) was introduced into the lead salt solution as a passivator to prepare perovskite films and solar cells via a two-step method. The impacts of acetylsalicylic acid on film quality and cell performance were investigated by means of optical spectroscopy, scanning electron microscopy and various electrical measurements. The results show that the introduction of appropriate amount of ASA can obviously increase the grain size of perovskite films and effectively reduce the defect density of perovskite films via Lewis acid-base interaction. The solar cell prepared with the incorporation of 2.5 mmol/L ASA achieves the highest photoelectric conversion efficiency of 19.83%, appreciably outperforming the control device (17.47%). This work highlights the efficacy of ASA in passivating defects of perovskite films and provides a facile method to improve the performance of perovskite solar cells.