水杨酸的添加对全无机锡铅混合钙钛矿太阳能电池的影响

全无机钙钛矿太阳能电池(PSCs)因其优异的光电转换效率和高的环境稳定性而被广大学者关注,但Pb元素的使用对环境危害较大限制了其进一步应用。尽管科研人员目前在努力寻找一种危害较小的元素替代铅,但无铅钙钛矿仍然比含铅钙钛矿更易分解,性能也更低。本文采用Sn部分取代Pb制备得到全无机锡铅混合钙钛矿薄膜,并通过添加一定量的水杨酸从而抑制Sn²⁺氧化为Sn⁴⁺,达到稳定相态提升电池光电转换效率的目的。结果表明随着水杨酸的添加量由2 mg·mL^-1增加至6 mg·mL^-1,器件的光电转换效率先增大后降低。通过SEM、XRD、XPS等测试结果发现,当添加量为4 mg·mL^-1时,薄膜相稳定性最好,与不添加水杨酸的器件相比,其短路电流密度(J_sc)从14.7 mA·cm^-2显著提高至15.1 mA·cm^-2,光电转换效率由5.8%提高至6.5%。此外,最优器件在空气环境中存放5 d后,初始光电转换效率仍可保持原有效率的50％,进一步表明水杨酸的添加对锡铅混合钙钛矿相稳定性的提升具有一定的促进作用。

Effect of Salicylic Acid Additive on the Properties of All-Inorganic Tin-Lead Perovskite Solar Cells

All-inorganic perovskite solar cells (PSCs) have gained significant attention due to their excellent photoelectric conversion efficiency and high stability. However, Pb-based perovskites are easily decomposed into toxic Pb compounds and are fatal to environment, which limit their further application. Despite the great effort carried out to substitute the Pb by a less hazardous element, lead-free perovskites still remain more unstable than lead-containing perovskites, and present lower performance as well. In this paper, Sn is used to partially replace Pb for obtaining all-inorganic tin-lead perovskite thin film, and salicylic acid is added for inhibiting the oxidation of Sn²⁺ to Sn⁴⁺, so as to achieve the goal of improving photoelectric conversion efficiency cells by a stable phase. The experimental results show that the photoelectric conversion efficiency of the device increases first and then decreases with the increase of the amount of salicylic acid from 2 mg·mL^-1 to 6 mg·mL^-1. Through the tests of SEM, XRD, XPS, it is found that the phase stability of the film is the best when the content of salicylic acid is 4 mg·mL^-1. Compared with the device without salicylic acid, the short-circuit current density (J_sc) increases from 14.7 mA·cm^-2 to 15.1 mA·cm^-2significantly, meanwhile, the photoelectric conversion efficiency increases from 5.8% to 6.5%. In addition, the initial photoelectric conversion efficiency of the best device can still maintain 50% of the original efficiency after 5 d of storage in the air environment, which further proves that the addition of salicylic acid has a certain role in promoting the stability of tin-lead perovskite phase.