Interfacial Oxygen Vacancies as a Potential Cause of Hysteresis in Perovskite Solar Cells
Interfacial Oxygen Vacancies as a Potential Cause of Hysteresis in Perovskite Solar Cells
复制标题
界面氧空位是钙钛矿太阳能电池滞后的潜在原因
DOI：
10.1021/acs.chemmater.5b04019
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发表时间：
2016-02-09
影响因子：
8.6
通讯作者：
Meng, Sheng
中科院分区：
文献类型：
--
作者：
Zhang, Fan;Ma, Wei;Meng, Sheng
有机金属卤化物钙钛矿太阳能电池(PSCs)已经成为最有前途的光伏技术之一，光伏效率超过20.3%。然而，在PSC商业化之前，必须解决包括电流电压扫描中的滞后在内的器件稳定性问题。瞬时吸收测量和第一性原理计算表明，在电压扫描过程中，在电场作用下，氧空位在二氧化钛电极中的迁移导致了PSCS中的反常滞后现象。氧空位在电极/钙钛矿界面的积累减缓了电荷提取的速度，但显着加快了界面上的电荷复合。此外，非绝热分子动力学模拟表明，界面处的电荷复合速率敏感地依赖于氧空位的位置(相差1个数量级)。通过有意地减少二氧化钛电极中的氧空位，我们基本上抑制了PSC器件中不利的磁滞。这项工作在PSCs的微观界面结构和宏观器件性能之间建立了牢固的联系，为未来的器件设计和优化提供了重要的线索。
Organometal halide perovskite solar cells (PSCs) have emerged as one of the most promising photovoltaic technologies with efficiencies exceeding 20.3%. However, device stability problems including hysteresis in current voltage scans must be resolved before the commercialization of PSCs. Transient absorption measurements and first-principles calculations indicate that the migration of oxygen vacancies in the TiO2 electrode under electric field during voltage scans contributes to the anomalous hysteresis in PSCs. The accumulation of oxygen vacancies at the electrode/perovskite interface slows down charge extraction while significantly speeding up charge recombination at the interface. Moreover, nonadiabatic molecular dynamics simulations reveal that the charge recombination rates at the interface depend sensitively (with 1 order of magnitude difference) on the locations of oxygen vacancies. By intentionally reducing oxygen vacancies in the TiO2 electrode, we substantially suppress unfavorable hysteresis in the PSC devices. This work establishes a firm link between microscopic interfacial structure and macroscopic device performance of PSCs, providing important clues for future device design and optimization.