Structural, optical and photoelectrochemical properties of p type Ni doped CuFeO2 by hydrothermal method

Abstract

Great efforts have been devoted to delafossite CuFeO2 for exploring its potential application in solar energy conversion. In this study, the structural, band gap, photoelectrochemical properties of pure and Ni doped delafossite CuFeO2 powders synthesized by hydrothermal method were investigated. XRD patterns confirm the formation of a majority of 3R and a small amount of 2H mixed delafossite CuFeO2 crystals. UV-VIS-NIR spectra display gradual narrowing trend of direct band gaps from 3.43 eV to 3.02 eV and indirect band gaps from 1.03 eV to 0.59 eV after Ni doping. The corresponding carrier concentration is promoted from 7.95 × 1019 to 1.14 × 1020 cm−3 together with the anodic shift of flat band potential. The photoresponse performance is enhanced by utilization of Ni doping, mainly due to the evidently narrowed band gap with promoted light absorption ability. The transient decay time of 6% Ni doped CuFeO2 is evidently prolonged from 5.0s to 11.0s, indicating the lower carrier recombination rate as compared with pure CuFeO2. The reduced semicircle radius in EIS spectra indicates the smaller charge transfer resistance and higher interfacial carrier transfer efficiency for Ni doped CuFeO2. In addition, Ni doped CuFeO2 exhibits slightly enhanced magnetic performance which is very easily to be recycled and beneficial for the potential application in suspended status.