钙钛矿太阳能电池（PSCs）的寿命被认为是关键因素。由于有机成分的存在，钙钛矿薄膜在高温、高湿、高氧条件下容易发生不可逆相变或快速分解为PbI₂。虽然外部物理封装可以通过避免自然环境下水蒸气的侵入，显著提高PSC器件的稳定性和寿命，但钙钛矿薄膜的内在稳定性较差，仍然制约着PSC器件的寿命。高温退火和冷却过程中产生的残余应力是导致钙钛矿薄膜固有稳定性差的不可否认的因素。基于以上问题，中南大学阳军亮课题组研究提出了一种表面微蚀和重建策略，以调节三阳离子钙钛矿膜中的应力。
优化后的PSC器件在开路电压（Voc）为1.2V时的PCE为25.54%，未封装器件在20%RH下存储40天可保持90%以上的初始效率，在N2连续照明下MPP跟踪时可保持83%的原始性能。同时，对于面积为10.4cm²的迷你模块，PCE达到21.02%。本研究为有效调节钙钛矿膜表面残余应力提供了一种表面微蚀刻和重构的新途径。
Figure 1.a)Schematic diagrams of conventional in-situ formation of 2D perovskite and microetching and reconstruction process on the surface of perovskite film using LA/IPA mixed solution. Top-view SEM images of (b)control, (c)LA/IPA, (d)OAI and (e) LA/IPA-15/OAI treated perovskite films. AFM images of (f) control, (g)LA/IPA, (h) OAI and (i) LA/IPA-15/OAI treated perovskite films.
Figure 2. a), b) Transmission FTIR spectra of pure LA and LA+FAI solutions. c) The proportion (atomic ratio, and weight ratio) of surface Pb content of different films obtained from X-ray photoelectron spectroscopy (XPS) spectra. d) XRD pattern of different perovskite films. e) A small range of XRD patterns of OAI, LA/IPA-10/OAI, LA/IPA-15/OAI and LA/IPA-20/OAI treated perovskite films. f) Tauc plots of the control, OAI, and LA/IPA-15/OAI treated perovskite films. g) and h) UPS spectra of different perovskite films. i) Schematic diagram of the energy level structure of films with different treatment methods.
Figure 3. GIXRD patterns of a) control, b) OAI-treated and c) LA/IPA-15/OAI-treated perovskite films. d) Linear fit of 2θ-sin2ψ for perovskite films. e) Schematic diagram of residual stress on the surface of ideal, control, OAI-treated and LA/IPA-15/OAI-treated perovskite films (from left to right).
Figure 4. a) Steady-state PL and b) TRPL analysis of the control and LA/IPA-15/OAI treated perovskite films. c) Light intensity dependence on Voc for the different devices. d) EIS spectra of control and LA/IPA-15/OAI modified devices under the dark conditions. Insert is equivalent circuit diagram.
本文来源DOI:10.1039/d4ee04248d
https://pubs.rsc.org/en/content/articlelanding/2024/ee/d4ee04248d