近日，我院研究生陈红钰以第一作者身份在国际顶级期刊Chemical Engineering Journal （SCI一区TOP，IF=13.2）上发表题为“Reductive 1-Thioglycerol Enables Multi-Stage Defect Passivation for Air-Processed Perovskite Solar Cells”的钙钛矿太阳能电池领域最新研究进展。其中，杭州电子科技大学（电子信息学院&碳中和新能源研究院）为论文第一单位，杭州电子科技大学李国栋特聘副教授和杭州电子科技大学严文生教授为论文通讯作者。
钙钛矿材料的软离子晶格对无水无氧的制造要求严格，可以减缓钙钛矿太阳能电池（PSCs）的老化。在本文中，开发了一种基于1-硫代甘油（1-ThL）的环境空气处理策略。通过利用硫醇-二硫化物氧化还原梭机制，通过电子转移过程抑制了I−的氧化和Pb0的形成，并在PSCs的整个生命周期中持续修复缺陷。1-ThL的电子离域效应还可以有效优化钙钛矿薄膜的结晶动力学，并抑制缺陷的形成。最终，在钙钛矿前驱体溶液中加入微量1-ThL后，在自然环境湿度下制造的PSCs的冠军功率转换效率（PCE）达到了25.34%。同时，老化后的钙钛矿前驱体溶液制备的PSCs保持了相对较高的PCE。此外，未封装PSCs在相对湿度为35±5%的潮湿空气环境中老化180天后，保留了超过80%的初始PCE。1-ThL的引入成功延长了钙钛矿前驱体溶液的储存期，提高了PSCs的PCE和稳定性，并为潮湿空气环境中的空气处理PSCs提供了一种极好的策略。
在接下来的研究中，我们将构建一套完整、高效、低成本的“全天候”空气制备钙钛矿太阳能电池技术体系，尽可能解决其环境敏感性和稳定性瓶颈，助推钙钛矿光伏技术的大规模产业化应用。这项工作的成功，不仅意味着钙钛矿电池可以在更多元的气候条件下生产和使用，更将极大降低其制造成本，为全球碳中和目标贡献自己的一份力量。
Figure 1 a) Molecular structure with passivation mechanism and ESP of glycerol and 1-ThL. b) Photographs of color changes for FAI solution in control, glycerol and 1-ThL, respectively. c-e) UV-Vis absorption spectra of the FAI solution in IPA solvent aging under light. f) Line chart of absorbance changes of three samples. g) The CV traces of I2+KCl+KI with/without 1-ThL in deionized water. (A-0.15 mg/mL, B-0.3 mg/mL, C-0.45 mg/mL, D-0.6 mg/mL, E-0.75 mg/mL in H2O) h) Scheme showing that I2/I3-was generated during the aging of the perovskite precursor solution that can be reduced back to I- after adding 1-ThL.
Figure 2 a) Pb 4f and b) I 3d XPS spectra of control and target, respectively. c) FTIR spectra in the wavenumber ranges 500-4000 cm-1. d) and f) In situ PL characteristics of perovskite under continuous laser irradiation. e) and g) In situ PL luminescence intensity variation. h) Macroscopic photograph of the crystallization process of perovskite films in N2 environment. i) Pb 4f XPS of aged perovskite films in control and target.
Figure 3 a) and b) Top-view SEM images of perovskite films. c) XRD patterns of (110) diffraction peaks for control and target. d) and e) Depth-dependent GIXRD patterns varying with incident angle of fresh perovskite film. f) Angular rate of GIXRD in fresh film. g) and h) Depth-dependent GIXRD patterns varying with incident angle of aged perovskite film. i) Angular rate of GIXRD in aged perovskite film.
Figure 4 a) FAPbI3 defects, b) FA defect, c) I defect on the perovskite surface. d) Adsorption energy statistics histogram. e) PL and f) TRPL spectra of the perovskite films prepared on glass. g) KPFM images of control and target films. h) Control and i) target SCLC test for electron-only devices (ITO/SnO2/PVK/PCBM/Ag). j) Nyquist plots of the PSCs based on control and target. k) Mott-Schottky analysis of the devices. l) Transient photocurrent decay measurements of both devices. m) Perovskite defect mechanism diagram. n) Energy level diagram of each part in the device.
Figure 5 a) Formal device structure image. b) Forward scan and reverse scan devices of the corresponding devices. c) EQE spectra and the corresponding integrated photocurrent for the control and target devices. d) J-V curves of the target device with an active area of 75 cm2. e) VOC and f) JSC dependence on light intensity. g) PSCs parameters obtained from the J-V curves based on the statistics of 30 devices for PCE of both devices. h) Storage stability of the control and target devices in a dry air environment. In situ PL spectra of film stability of i) control and j) target at 80℃ and 60% RH. k) State power output measurements for the champion PSCs of control and target devices. l) Operational stabilities of the unencapsulated PSCs at maximum power point under one-sun illumination at 25 ± 5 °C.