Title:Narrow-Bandgap Semiconductors of Perovskite Rare-Earth Orthoferrites (REFeO3)
Volume: 1
Issue: 4
Author(s): Lei Chen*, Ting Jiang, Guifang Zheng, Gang Yao, Lei Wang, Yuanjun Yang, Haiwu Zheng, Yang Jiang, Yingwei Lu and Shizhong Wei *
Affiliation:
- School of Materials Science and Engineering, Hefei University of Technology, Hefei,China
- National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials, & Henan Key Laboratory of High-temperature Structural and Functional Materials, Henan University of Science and Technology, Luoyang,China
Keywords:
Absorbers, rare earth, semiconductors, perovskite, crystal and electronic structures, orthoferrites.
Abstract:
Background: Great achievements have been made in improving the power conversion efficiencies
of solar cells. However, the price of photovoltaic (PV)-generated electricity still cannot compete
with that of conventionally generated power. Thus, novel solar cells made from non-toxic, earth-abundant,
and chemically stable materials are desirable to decrease the costs of PV electricity generation.
Objective: All-oxide solar cells are a promising next-generation PV technology, fulfilling the requirement
of low-cost manufacturing under ambient conditions. This work aims to search for nontoxic,
earth-abundant, and chemically stable narrow-bandgap semiconductors for energy applications
like all-oxide solar cells.
Methods: This work examines a family of perovskite rare-earth (i.e., Y, La, Ce, Pr, Nd, Sm, Gd, Tb,
Dy, Ho, Er, and Yb) orthoferrites with XRD analysis, SEM, photoresponse, absorption spectra, Xray
photoelectron spectroscopy, fluorescence spectra measured with the laser Raman spectrometer,
valence band spectra, the Kelvin probe, the Hall Effect experiment, and theoretical calculation on
band structure and the density of states, to screen for the narrow-bandgap semiconductors.
Results: The novel Pb-free perovskite narrow-bandgap absorbers, CeFeO3, PrFeO3, TbFeO3,
DyFeO3, HoFeO3, and YbFeO3, which are earth-abundant and non-toxic, were screened out potentially
for use in all-oxide solar cells or other photovoltaic and optoelectronic applications. Among
them, YbFeO3 is approved, having an indirect bandgap of approximately 1.0 eV with a maximum
Shockley-Queisser efficiency of 31% for single p-n junction solar cells.
Conclusion: The chemically stable, non-toxic, earth-abundant, and narrow-bandgap semiconductors
of rare-earth orthoferrites promisingly serve as absorbers, photocatalysts, photoelectrodes, photodetectors,
and photoelectronic materials. This work breaks new ground in the search for narrow
bandgap all-oxide semiconductors potential for energy applications.
