Elucidation of Quantum-Well-Specific Carrier Mobilities in Layered Perovskites
Elucidation of Quantum-Well-Specific Carrier Mobilities in Layered Perovskites
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层状钙钛矿中量子阱特定载流子迁移率的阐明
DOI：
10.1021/acs.jpclett.0c03596
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Moran, Andrew M.
中科院分区：
文献类型：
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作者：
Zhou, Ninghao;Ouyang, Zhenyu;Yan, Liang;McNamee, Meredith G.;You, Wei;Moran, Andrew M.
层状有机卤化物钙钛矿薄膜由量子威尔斯阱组成，量子阱具有定制的浓度分布以增强长程电荷传输。尽管级联能量和电荷漏斗行为已经用传统光谱法检测到，但尚不清楚这种动态是否有助于光伏电池的效率。在这封信中，我们使用非线性光电流光谱选择性地针对基于层状钙钛矿量子威尔斯的器件内的电荷传输过程。由一对激光脉冲引起的光电流直接测量在这个“行动”光谱，以消除信号解释的模糊性。通过改变外部偏压，我们确定载流子迁移率的量子阱特定的轨迹通过有源层的设备。结果表明，最大的量子威尔斯是主要负责光电流的生产，而最小的量子威尔斯陷阱电荷载流子，是光伏电池中的能量损失的主要来源。
Layered organohalide perovskite films consist of quantum wells with concentration distributions tailored to enhance long-range charge transport. Whereas cascaded energy and charge funneling behaviors have been detected with conventional optical spectroscopies, it is not clear that such dynamics contribute to the efficiencies of photovoltaic cells. In this Letter, we use nonlinear photocurrent spectroscopy to selectively target charge transport processes within devices based on layered perovskite quantum wells. The photocurrent induced by a pair of laser pulses is directly measured in this “action” spectroscopy to remove ambiguities in signal interpretation. By varying the external bias, we determine carrier mobilities for quantum-well-specific trajectories taken through the active layers of the devices. The results suggest that the largest quantum wells are primarily responsible for photocurrent production, whereas the smallest quantum wells trap charge carriers and are a major source of energy loss in photovoltaic cells.