Luan Fuyuan, Li Haiyan, Gong Shuiping, Chen Xinyu, Shou Chunhui, Wu Zihua, Xie Huaqing, Yang Songwang
School of Energy and Materials, Shanghai Polytechnic University, Shanghai 201209, People's Republic of China.
CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Shanghai 201899, People's Republic of China.
Nanotechnology. 2022 Nov 18;34(5). doi: 10.1088/1361-6528/ac9f4f.
The perovskite film prepared by the two-step spin coating method is widely used in photovoltaic devices due to its good film morphology and great reproducibility. However, there usually exists excessive lead iodide (PbI) in the perovskite film for this method, which is believed to passivate the grain boundaries (GBs) to increase the efficiency of the perovskite solar cells. Nevertheless, the excessive PbIat the GBs of perovskite is believed to induce the decomposition of the perovskite film and undermine the long-term stability of devices. In this study, we utilize precursor engineering to realize the preparation of perovskite solar cells with high efficiency and stability. The concentration of organic salts (AX: A = MA, FA; X = I, Cl) in the precursor solution for the second step of the two-step spin coating method is adjusted to optimize the perovskite light-absorbing layer so that the excessive PbIis converted into perovskite to obtain a smooth and pinhole-free perovskite film with high performance. Our results indicate that by adjusting the concentration of AX in the precursor solution, PbIin the film could be completely converted into perovskite without excessive AX residue. Both the efficiency and stability of the perovskite solar cells without excessive PbIhave been significantly improved. A planar perovskite solar cell with the highest power conversion efficiency (PCE) of 21.26% was achieved, maintaining about 90% of the initial PCE after 300 h of storage in a dry air environment and in the dark, about 76% of the initial PCE after 300 h of continuous illumination of 1 Sun.
通过两步旋涂法制备的钙钛矿薄膜因其良好的薄膜形态和高重现性而被广泛应用于光电器件中。然而，该方法制备的钙钛矿薄膜中通常存在过量的碘化铅（PbI），据信其可钝化晶界以提高钙钛矿太阳能电池的效率。尽管如此，钙钛矿晶界处过量的PbI被认为会导致钙钛矿薄膜分解并破坏器件的长期稳定性。在本研究中，我们利用前驱体工程实现了高效且稳定的钙钛矿太阳能电池的制备。通过调整两步旋涂法第二步前驱体溶液中有机盐（AX：A = MA、FA；X = I、Cl）的浓度来优化钙钛矿吸光层，使过量的PbI转化为钙钛矿，从而获得具有高性能的光滑且无针孔的钙钛矿薄膜。我们的结果表明，通过调整前驱体溶液中AX的浓度，薄膜中的PbI可完全转化为钙钛矿，且无过量AX残留。不含过量PbI的钙钛矿太阳能电池的效率和稳定性均得到显著提高。实现了平面钙钛矿太阳能电池的最高功率转换效率（PCE）为21.26%，在干燥空气环境和黑暗中储存300小时后，保持初始PCE的约90%，在1个太阳的连续光照300小时后，保持初始PCE的约76%。
