Electronic and optical properties of Cr and Cr-N doped anatase TiO2 from screened Coulomb hybrid calculations

TL;DR

This study uses hybrid density functional theory to analyze how Cr and N doping alter the electronic structure of anatase TiO2, reducing its band gap and enhancing its potential for photoactivity.

Contribution

It introduces a hybrid functional approach to accurately model doped TiO2, revealing the effects of Cr and N on electronic properties and magnetization.

Findings

Cr and N doping significantly reduce the band gap of TiO2.

Doped TiO2 exhibits improved potential for photoactivity.

Hybrid functional calculations better describe impurity states.

Abstract

We studied the electronic and atomic structures of anatase TiO2 codoped with Cr and N using hybrid density functional theory calculations. Nonlocal screened Hartree-Fock exchange energy is partially mixed with traditional semilocal exchange part. This not only heals the band gap underestimation but also improves the description of anion/cation-driven impurity states and magnetization of the dopants. Cr and/or N doping modifies the valence and conduction band edges of TiO2 leading to significant band gap reduction. Hence, Cr, N and Cr-N doped TiO2 are promising for enhanced photoactivity.