Alsari Mejd, Pearson Andrew J, Wang Jacob Tse-Wei, Wang Zhiping, Montisci Augusto, Greenham Neil C, Snaith Henry J, Lilliu Samuele, Friend Richard H
Cavendish Laboratory, University of Cambridge, CB30HE, Cambridge, UK.
Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, Oxford, UK.
Sci Rep. 2018 Apr 13;8(1):5977. doi: 10.1038/s41598-018-24436-6.
We explore the degradation behaviour under continuous illumination and direct oxygen exposure of inverted unencapsulated formamidinium(FA)CsPb(IBr), CHNHPbI, and CHNHPbICl perovskite solar cells. We continuously test the devices in-situ and in-operando with current-voltage sweeps, transient photocurrent, and transient photovoltage measurements, and find that degradation in the CHNHPbICl solar cells due to oxygen exposure occurs over shorter timescales than FACsPb(IBr) mixed-cation devices. We attribute these oxygen-induced losses in the power conversion efficiencies to the formation of electron traps within the perovskite photoactive layer. Our results highlight that the formamidinium-caesium mixed-cation perovskites are much less sensitive to oxygen-induced degradation than the methylammonium-based perovskite cells, and that further improvements in perovskite solar cell stability should focus on the mitigation of trap generation during ageing.
我们研究了倒置无封装的甲脒（FA）铯铅（碘溴）、甲胺铅碘和甲胺铅碘氯钙钛矿太阳能电池在持续光照和直接氧气暴露下的降解行为。我们通过电流-电压扫描、瞬态光电流和瞬态光电压测量对器件进行原位和实时操作测试，发现与FA铯铅（碘溴）混合阳离子器件相比，甲胺铅碘氯钙钛矿太阳能电池因氧气暴露导致的降解发生在更短的时间尺度上。我们将这些功率转换效率中由氧引起的损失归因于钙钛矿光活性层内电子陷阱的形成。我们的结果表明，甲脒-铯混合阳离子钙钛矿对氧诱导的降解比基于甲胺的钙钛矿电池敏感得多，并且钙钛矿太阳能电池稳定性的进一步提高应集中在减轻老化过程中陷阱的产生上。
