Charge Carrier Recombination at Perovskite/ Hole Transport Layer Interfaces Monitored by Time-Resolved Spectroscopy
Charge Carrier Recombination at Perovskite/ Hole Transport Layer Interfaces Monitored by Time-Resolved Spectroscopy
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DOI：
10.1021/acsenergylett.1c01931
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发表时间：
2021-11-01
影响因子：
22
通讯作者：
Laquai, Frederic
中科院分区：
文献类型：
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作者：
Khan, Jafar, I;Isikgor, Furkan H.;Laquai, Frederic
在太阳能电池中电荷提取层和钙钛矿光敏层之间的界面处的载流子复合降低了准费米能级分裂（QFLS），并因此降低了器件的开路电压（VOC）。界面载流子复合和电荷提取之间的区分需要选择性探测载流子动态与瞬态光谱技术。然而，体复合，界面复合，和电荷提取都有助于瞬态响应，使个别率的精确测定具有挑战性。在这里，我们比较了两种常用的空穴传输层（HTL），即PTAA和NiOx，与原型MAPI 3钙钛矿光活性层和宽带隙钙钛矿相邻。我们证明，结合时间分辨光致发光（TR-PL）和瞬态吸收（TA）光谱测量可以揭示与钙钛矿/NiOx界面相关的复合损失，如漂移扩散模拟所证实的。性能最好的基于MAPI 3/PTAA的器件表现出更少的非辐射复合和更有效的电荷提取，这得益于有利的能级对准。
Carrier recombination at the interface between charge extraction layers and the perovskite photoactive layer in solar cells reduces the quasi-Fermi level splitting (QFLS) and hence the device's open-circuit voltage (VOC). Distinguishing between interfacial carrier recombination and charge extraction requires selective probing of carrier dynamics with transient optical spectroscopy techniques. However, bulk recombination, interfacial recombination, and charge extraction all contribute to the transient response, making a precise determination of individual rates challenging. Here, we compare two commonly used hole transport layers (HTLs), namely, PTAA and NiOx, adjacent to prototypical MAPI3 perovskite photoactive layers and wide-bandgap perovskites. We demonstrate that combining time-resolved photoluminescence (TR-PL) and transient absorption (TA) spectroscopy measurements can reveal recombination losses associated with the perovskite/NiOx interface, as confirmed by drift-diffusion simulations. The best performing MAPI3/PTAA-based device exhibits less nonradiative recombination and more efficient charge extraction, facilitated by favorable energy level alignment.