Semiconducting ferroelectric perovskites with intermediate bands viaB-siteBi5+doping

Abstract

We propose B-site Bi 5+ -doped ferroelectric perovskite materials as suitable candidates for the bulk photovoltaic effect and related solar applications. The low-lying 6s empty states of the electronegative Bi atom produce empty bands in the energy gap of the parent materials, effectively lowering the band gap by 1-2 eV, depending on the composition of the ferroelectric end member and the concentration of Bi 5+ in the solid solution. The polarization decreases but survives upon doping, which enables the "shift current" mechanism for photocurrent generation, while the decreased band gap allows absorption of much of the visible spectrum. The magnitude of shift current response is calculated for 0.75Pb 2 InNbO 6 -0.25Ba 2 InBiO 6 (PIN-BIB) and 0.75Pb 2 ScNbO 6 -0.25Sr 2 ScBiO 6 (PSN-SSB) and is predicted to exceed the visible light bulk photovoltaic response of all previously reported materials, including BiFeO 3 . Furthermore, the existence of their intermediate bands and multiple band gaps, combined with Fermi level tuning by A-site co-doping, also allows for their potential application in traditional p − n junction-based solar cells as broadspectrum photoabsorbers.

Research progress of perovskite materials in photocatalysis- and photovoltaics-related energy conversion and environmental treatment

“…[176][177][178][179][180] Ferroelectric oxides are also stable in a wide range of mechanical, chemical and thermal conditions and can be fabricated using low-cost methods, such as sol-gel thin-film deposition and sputtering. [176][177][178][179][180] Ferroelectric oxides are also stable in a wide range of mechanical, chemical and thermal conditions and can be fabricated using low-cost methods, such as sol-gel thin-film deposition and sputtering.…”

First-principles calculation of the bulk photovoltaic effect inKNbO3and (K,Ba)(Ni,Nb)O3−δ

“…Thus an enormous amount of effort has been focused on the design and optimization of FE materials in order to reach a lower band gap [4,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Among them, the study and improvement of ferroelectric oxides are important, as these materials can be integrated into conventional electronics [26][27][28][29][30][31][32][33][34].…”

First-Principles Materials Design of High-Performing Bulk Photovoltaics with theLiNbO3Structure

“…The ab initio calculation of the shift current and subsequent analysis yielded several chemical and structural criteria for optimizing the response. These criteria have been used previously to modify or identify existing materials with enhanced response [14,[32][33][34]. In this work, we use these insights to propose several candidate bulk photovoltaics with calculated response as much as an order of magnitude higher than well-known ferroelectrics, while having band gaps in or slightly below the visible spectrum.…”

“…To overcome the weak BPVE response of d 0 oxides, we investigated systems that involve both large distortions to oxygen cages, (increasing the bonding character of any d 0 states) as well as d 10 cations with less localized s and/or p states near the band edge [32]. It has already been noted that d 10 cations can dramatically improve the activity of photocatalysts [50].…”