Yttrium Doped α-Fe2O3 Nanorods for Enhanced Optoelectronic Properties and Increased Photocurrent Density

Abstract

Hematite (α-Fe₂O₃) has received a lot of attention and has potential use in a variety of applications such as energy storage and photovoltaic solar cells despite its short diffusion length and extremely low conductivity. A possible strategy to enhance its structural and optoelectronic properties is element doping. In this work, we report on the successful preparation of α-Fe₂O₃ nanorods thin film via a simple low-cost hydrothermal process, and the crucial effect of yttrium doping. We analyzed the effects of Y-doping of α-Fe₂O₃ by varying the amount of yttrium 1, 3, 5, and 8 at %. The optical study revealed that Y-doping reduces the optical band gap, with a shift from 2.11 eV for pure hematite NRs films to 1.94 eV for 5 at % Y-doped NRs. Our study proved that Y-doping obviously reduced the recombination activities in α-Fe₂O₃ as demonstrated by the photoluminescence study. Amongst all doped α-Fe₂O₃ NRs films with different Y dopant concentration, the 5 at % exhibited best structural and optoelectronic properties with the highest photocurrent density and incident photon to current efficiency (IPCE). The photocurrent density was increased from 0.25 (undoped) to 1.25 mA/cm² in the doped NRs with 5 at % Y content at 0.4 V vs. (Ag/AgCl) under illumination, which is 5 times higher than that measured in the pristine α-Fe₂O₃. The high photo-response of Y-doped NRs in the visible range suggests that the grown NRs thin films are excellent candidates for optoelectronic applications, particularly in solar cells and large light-harvesting devices.