Photovoltaic conversion and quantum efficiency in perovskite multiferroic ceramics. (1st May 2018) - Tu, Chi-Shun
Abstract: Junction-driven photovoltaic effects in lead-free perovskite BiFeO3 multiferroic materials have demonstrated promising applications in energy harvesting and optical sensors. This study highlights remarkable photon-to-electron external quantum efficiency (EQE) of ∼9% and light-to-electric power-conversion efficiency (PCE) of ∼0.8% in the heterostructure consisting of A-site neodymium-doped BiFeO3 ceramic and indium-tin-oxide (ITO) thin film under irradiation of wavelength λ = 405 nm. A theoretical p-n-junction model based on the photo-generated carriers was employed to quantitatively describe open-circuit voltage (Voc ) and short-circuit current density (Jsc ) as functions of irradiation intensity, and to calculate junction widths and carrier densities. The direct band gap and the degree of local disorder (or defect state) were estimated using the photon-energy-dependent optical attenuation coefficient with the Tauc and Urbach relations. Graphical abstract: Image 1