Passivation Strategy of Reducing Both Electron and Hole Trap States for Achieving High-Efficiency PbS Quantum-Dot Solar Cells with Power Conversion Efficiency over 12%
Passivation Strategy of Reducing Both Electron and Hole Trap States for Achieving High-Efficiency PbS Quantum-Dot Solar Cells with Power Conversion Efficiency over 12%
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DOI：
10.1021/acsenergylett.0c01561
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发表时间：
2020-10-09
影响因子：
22
通讯作者：
Shen, Qing
中科院分区：
文献类型：
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作者：
Ding, Chao;Liu, Feng;Shen, Qing
对于目前的钝化策略，固态配体交换(SSE)中的纯碘钝化不能完全钝化PbS胶体量子点(CQD)的整个表面。在此，提出了一种简单的分步钝化策略，该策略是基于PbS CQD膜在碘钝化后用卤素(C_1、B_r或I)延迟钝化。这种延迟钝化可以弥补SSE过程中极地环境造成的配体缺失。因此，电子态和空穴捕获态都大大减少，CQD薄膜中的电荷输运得到显著改善。经氯处理后的PbS CQD薄膜的载流子扩散长度比对照样品增加了70%。到目前为止，在报道的用SSE方法制备的PbS CQD太阳电池中，我们展示了最高的功率转换效率，达到12.4%。此外，该器件在空气中表现出良好的稳定性。
For the current passivation strategy, pure iodine passivation during solid-state ligand exchange (SSE) cannot completely passivate the entire surface of PbS colloidal quantum dots (CQDs). Here, a simple stepwise passivation strategy is proposed based on the postpassivation of PbS CQD films with a halogen (C1, Br, or I) after iodine passivation through the SSE. This postpassivation could desoq compensate for the missing ligands caused by the polar environment during the SSE. Thus, both electron- and hole-trapping states are greatly reduced, and the charge transport in the CQD film is significantly improved. The PbS CQD films post-treated with chlorine exhibit a carrier diffusion length increased by 70% when compared with that of control samples. We demonstrate the highest power conversion efficiency of 12.4% among the reported PbS CQD solar cells prepared with the SSE method to date. In addition, the unencapsulated device shows good stability in air.