Enhanced Photovoltaic Performance in Polycrystalline BiFeO3 Thin Film/ZnO Nanorod Heterojunctions

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• 作者：Fen Wu ; Yiping Guo ; Yangyang Zhang ; Huanan Duan ; Hua Li ; Hezhou Liu
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 17, 2014
• 年：2014
• 卷：118
• 期：28
• 页码：15200-15206
• 全文大小：409K
• ISSN：1932-7455

文摘

We demonstrate that the insertion of an n-type ZnO nanorod (NR) layer between a polycrystalline BiFeO₃ (BFO) thin film and a poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) buffer layer in a sandwich-like F-doped SnO₂ (FTO)/BFO/PEDOT:PSS/Au capacitor leads to the short-circuit current (J_sc) increasing 64-fold from 16.8 渭A/cm² to 1.08 mA/cm² under the AM1.5G (100 mW/cm²) illumination. When the semitransparent Au electrode is substituted by a transparent Al-doped ZnO (AZO) electrode, the photovoltaic (PV) output can be further improved, with the power conversion efficiency (PCE) reaching 0.17%, which is to our knowledge the highest efficiency that has ever been obtained in the all-solid-state BFO-based capacitor solar devices. It is proposed that the polarization induced FTO/BFO Schottky barrier, the low-resistance ZnO NR/PEDOT:PSS contact, and the carrier transportation characteristics of ZnO NRs contribute to the PV enhancement. A band bending diagram model considering ferroelectric polarization and interface states as well as a schematic energy level diagram of the FTO/BFO/ZnO NR/PEDOT:PSS/Au device is constructed to illustrate the PV enhancement. Our work may provide a new way to utilize ferroelectrics to improve the power conversion efficiency of heterojunction based solar cells and to produce solar cells with tunable PV response and other novel functions.