Zhang Yuanzheng, Yang Liya, Zhang Yaju, Ding Zhenyu, Wu Mengjun, Zhou Yan, Diao Chunli, Zheng Haiwu, Wang Xingfu, Wang Zhong Lin
International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004, P.R. China.
Institute of Semiconductor Science and Technology, South China Normal University, Guangzhou 510631, P.R. China.
ACS Nano. 2020 Aug 25;14(8):10723-10732. doi: 10.1021/acsnano.0c05398. Epub 2020 Aug 11.
Ferroelectric materials have drawn widespread attention due to their switchable spontaneous polarization and anomalous photovoltaic effect. The coupling between ferroelectricity and the piezo-phototronic effect may lead to the design of distinctive photoelectric devices with multifunctional features. Here, we report an enhancement of the photovoltaic performances in the ferroelectric -type La-doped bismuth ferrite film (BLFO)/-type zinc oxide (ZnO) nanowire array heterojunction by rationally coupling the strain-induced piezoelectricity in ZnO nanowires and the ferroelectricity in BLFO. Under a compressive strain of -2.3% and a 10 V upward poling of the BLFO, the open-circuit voltage () and short-circuit current density ) of the device increase by 8.4% and 54.7%, respectively. Meanwhile, the rise (/decay) time is modulated from 153.7 (/108.8) to 61.28 (/74.86) ms. Systematical band diagram analysis reveals that the promotion of photogenerated carriers and boost of the photovoltaic performances of the device can be attributed to the modulated carrier transport behaviors at the BLFO/ZnO interface and the superposed driving forces arising from the adding up of the piezoelectric potential and ferroelectric polarization. In addition, COMSOL simulation results of piezopotential distribution in ZnO nanowire arrays and the energy band structure change of the heterojunction further confirm the mechanisms. This work not only presents an approach to design high-performance ferroelectric photovoltaic devices but also further broadens the research scope of piezo-phototronics.
铁电材料因其可切换的自发极化和异常光伏效应而受到广泛关注。铁电性与压光电子效应之间的耦合可能会导致设计出具有多功能特性的独特光电器件。在此，我们报告了通过合理耦合氧化锌（ZnO）纳米线中的应变诱导压电性和掺镧铋铁氧体薄膜（BLFO）中的铁电性，提高了铁电型掺镧铋铁氧体薄膜（BLFO）/n型氧化锌（ZnO）纳米线阵列异质结的光伏性能。在-2.3%的压缩应变和BLFO的10 V正向极化下，该器件的开路电压（Voc）和短路电流密度（Jsc）分别增加了8.4%和54.7%。同时，上升（/衰减）时间从153.7（/108.8）毫秒调制到61.28（/74.86）毫秒。系统的能带图分析表明，光生载流子的促进和器件光伏性能的提高可归因于BLFO/ZnO界面处调制的载流子输运行为以及压电势和铁电极化叠加产生的叠加驱动力。此外，ZnO纳米线阵列中压电势分布的COMSOL模拟结果和异质结的能带结构变化进一步证实了这些机制。这项工作不仅提出了一种设计高性能铁电光伏器件的方法，还进一步拓宽了压光电子学的研究范围。
