Microwave-sintering enhanced photovoltaic conversion in polycrystalline Nd-doped BiFeO3

• Published in: Ceramics international Vol. 46; no. 13; pp. 20963 - 20973
• Main Authors: Chen, Pin-Yi, Chen, Jing-Ren
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2020
• Subjects: Domain evolution; External quantum efficiency; Microwave sintering; Photovoltaic; Polar nano-regions; Power conversion efficiency; Polar nano-regions; Domain evolution; Microwave sintering; Photovoltaic; External quantum efficiency; Power conversion efficiency
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2020.05.156

This work reports remarkable photovoltaic effects in the microwave-sintered lead-free perovskite (Bi0.93Nd0.07)FeO3 (B7NFO) ceramics with indium tin oxide (ITO) thin film under 405 nm blue irradiation. Maximal power conversion efficiency (PCE) ~1.2% and external quantum efficiency (EQE) ~17% can be obtained at low irradiation intensity. Optical absorption and photoluminescence emission suggest direct bandgap (Eg) in the range of 2.11–2.21 eV in B7NFO ceramics. Grain boundaries exhibit a lower electrical potential and higher electrical conductivity, and can act as conduction channels for the photo-generated charge carriers. High-resolution transmission electron microscopy (HR-TEM) suggests that field-enhanced photovoltaic effects are associated with large and highly ordered polar nano-regions (PNRs) in the matrix. Microwave-sintering process corresponds to a lower activation energy (433 kJ/mol) of grain growth than the conventional-sintering process (604 kJ/mol). This study demonstrates that the microwave-sintering process can be an effective and cost-less technique for energy-harvesting polycrystalline materials.