Chemical Interaction at the MoO3/CH3NH3PbI3-xClx Interface
Chemical Interaction at the MoO3/CH3NH3PbI3-xClx Interface
复制标题
MoO3/CH3NH3PbI3-xClx 界面的化学相互作用
DOI：
10.1021/acsami.1c01284
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发表时间：
2021
影响因子：
9.5
通讯作者：
Baer Marcus
中科院分区：
文献类型：
--
作者：
Liao Xiaxia;Habisreutinger Severin N.;Wiesner Sven;Sadoughi Golnaz;Abou-Ras Daniel;Gluba Marc A.;Wilks Regan G.;Felix Roberto;Rusu Marin;Nicholas Robin J.;Snaith Henry J.;Baer Marcus
金属卤化物钙钛矿基太阳能电池有限的长期稳定性是其广泛商业化应用的瓶颈。有机空穴传输材料(HTMS)参与了材料的降解，金属氧化层被提出作为替代材料。有机光伏中最突出的金属氧化物高温超导材料之一是MoO_3。然而，在金属卤化物钙钛矿基器件中使用MoO_3作为高温超导材料会导致太阳能电池的严重退化。因此，本文利用同步加速器硬X射线光电子能谱、扫描电子显微镜、能量色散X射线能谱和拉曼光谱系统地研究了MoO_3/CH_3NH_3PbI_3-xClx(MAPbI_3-xClx)异质结的形成过程。MoO_3沉积时，在MoO_3/MAPbI_3-xClx界面处发生了明显的化学相互作用：存在亚化学计量比的钼氧化物，钙钛矿在界面附近分解，导致PbI_2在MoO_3覆盖层上积累。此外，我们还发现了MAPbI3-xClx分解导致PbMoO4、PbN2O2和PbO等新化合物形成的证据，并提出了描述其潜在机制的化学反应途径。这些发现表明，(直接)MoO_3/MAPbI_3-xClx界面可能是固有的不稳定的。解释了以MoO_3为空穴传输材料且MoO_3与钙钛矿直接接触的金属卤化物钙钛矿太阳电池功率转换效率低的原因。
The limited long-term stability of metal halide perovskite-based solar cells is a bottleneck in their drive toward widespread commercial adaptation. The organic hole-transport materials (HTMs) have been implicated in the degradation, and metal oxide layers are proposed as alternatives. One of the most prominent metal oxide HTM in organic photovoltaics is MoO3. However, the use of MoO3as HTM in metal halide perovskite-based devices causes a severe solar cell deterioration. Thus, the formation of the MoO3/CH3NH3PbI3–xClx(MAPbI3–xClx) heterojunction is systematically studied by synchrotron-based hard X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. Upon MoO3deposition, significant chemical interaction is induced at the MoO3/MAPbI3–xClxinterface: substoichiometric molybdenum oxide is present, and the perovskite decomposes in the proximity of the interface, leading to accumulation of PbI2on the MoO3cover layer. Furthermore, we find evidence for the formation of new compounds such as PbMoO4, PbN2O2, and PbO as a result of the MAPbI3–xClxdecomposition and suggest chemical reaction pathways to describe the underlying mechanism. These findings suggest that the (direct) MoO3/MAPbI3–xClxinterface may be inherently unstable. It provides an explanation for the low power conversion efficiencies of metal halide perovskite solar cells that use MoO3as a hole-transport material and in which there is a direct contact between MoO3and perovskite.