用户前沿丨臧志刚&陈江照Nat. Energy：埋底界面2D/3D异质结工程实现高性能反式无甲铵钙钛矿太阳能电池

反式（p-i-n）钙钛矿太阳能电池具有与不同底电池兼容、可低温制备（≤100℃）、稳定性优异等优势。因此，反式电池的发展对于钙钛矿太阳能电池的商业化应用至关重要。近年来，反式电池引起了学术界和工业界广泛的关注，效率和稳定性取得了巨大的进展。然而，目前效率超过25%的反式电池仍然使用含MA+和Br-的钙钛矿吸光材料，常常使用MA+和Br-调节晶体生长和稳定α-FAPbI3的光活性黑色相。

然而，MA+在钙钛矿晶格中容易挥发和逸出，这会降低电池的光和热稳定性。此外，混合卤化物（I/Br）钙钛矿常常会发生相分离，这种现象会导致器件在光照和热老化下加速分解。空穴传输层/钙钛矿埋底界面常常存在大量的深能级陷阱态。埋底界面处的能量势垒导致界面空穴提取受阻，从而降低了器件的光伏性能。

总之，界面非辐射复合进一步降低反式器件的光伏性能。针对上述问题，重庆大学臧志刚和陈江照等人通过在无甲铵钙钛矿前驱液中引入少量的2-氨基茚满盐酸盐，在埋底界面原位形成了自下而上的2D/3D异质结，调控了钙钛矿结晶，钝化了3D钙钛矿晶界缺陷，优化了埋底界面能级排列，显著抑 制了埋底界面非辐射复合损失。

基于反式电池实现了25.12%（认证效率为24.6%）的效率，这是反式无甲铵钙钛矿太阳能电池报道的最 高效率。未封装电池最 大功率点持续跟踪1500小时后仍能保持初始效率的98%。封装的电池在85℃/85%RH老化1200小时后保持初始PCE的92%。

Fig. 1┃Structural characterizations of the bottom-up 2D/3D heterojunction at buried interface. a, ToF-SIMS profile of ITO/NiOx/PTAA/Al2O3/perovskite with bottom-up 2D/3D perovskite heterojunction at buried interface (2D spacer species: CN- and Cl-, ammonium salt: CN-). b, 2D GIWAXS mappings of the control and target perovskite films with different incidence angles. c, PL spectra of the target perovskite film obtained from different incident directions. The perovskite films were deposited on ITO/NiOx/PTAA/Al2O3substrate. d, Cross-sectional HRTEM image of the target PSC. e, Device configuration of the inverted PSCs with bottom-up 2D/3D perovskite heterojunction at buried interface.

Fig. 2┃Charge carrier dynamics. a,b, TRPL spectra of the control and target perovskite films deposited on a bare glass substrate (a) and glass/NiOx/PTAA/Al2O3 substrate (b). TRPL measurements were conducted with excitation from the glass side and with an emission wavelength of 810 nm. c,d, Transient reflection (TR) spectroscopy measurements for the control (c) and target (d) perovskite films on NiOx/glass substrate. TRS measurements were performed with excitation from glass side.

Fig. 3┃Device performance and stability. a, PCE histogram of 20 PSCs with (target) and without (control) bottom-up 2D/3D heterojunction at buried interface. b, J-V curves obtained in forward and reverse scans of the champion target PSCs. The insets show the relevant photovoltaic parameters. c, Comparison of the photovoltaic performance of the inverted PSC in this work with literatures which reported PCEs over 23%. More details are shown in Table S4. d,J-V curve of the best performing target device with an area of 1 cm2. The insets show the relevant photovoltaic parameters. e, PCE of the unencapsulated control and target devices measured at maximum power point under continuous one-sun illumination at 55 ± 5 °C in N2 atmosphere. The initial PCE of control, target-1, and target-2 devices are 21.73%, 24.42%, and 24.11%, respectively. f, Damp-heat stability of the encapsulated control and target devices following the ISOS standards (85 ℃/85% RH). The initial PCE of control and target devices are 22.15±0.13% and 24.32±0.20%. The error bar is the standard deviation of three devices.

论文链接：

https://www.nature.com/articles/s41560-023-01295-8

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重庆大学臧志刚和陈江照等人通过在无甲铵钙钛矿前驱液中引入少量的2-氨基茚满盐酸盐，自下而上形成的2D/3D异质结，钝化3D钙钛矿晶界缺陷，优化了埋底界面能级排列，显著抑 制了埋底界面非辐射复合损失。本研究利用爱丁堡FLS1000荧光光谱仪获取发光光谱，钙钛矿材料通常需要高功率脉冲激光器进行激发从而获取瞬态光谱信息，爱丁堡全新推出高功率皮秒脉冲激光器，拥有标准模式和高功率模式，重频可达到80MHz，欢迎各位老师垂询。