Electronic and optical properties of Cr-, B-doped, and (Cr, B)-codoped SrTiO3

Energy band engineering of semiconductors plays a crucial role in exploring high-efficiency visible-light response photocatalysts. Herein, we systematically study the electronic properties and optical response of Cr-, B-doped SrTiO 3 , and (Cr, B)-codoped SrTiO 3 by using first-principles calculations to explore the mechanism for its superior photocatalytic activities in the visible light region. Special emphasis is placed on uncovering the synergy effects of nonmetal B dopant with metal Cr dopant at different cation sites. It is found that the electronic properties and optical absorption of SrTiO 3 can be dramatically engineered by mono- or co-doping. In particular, the intermediate levels lying in the bandgap of the codoped SrTiO 3 relay on the Cr impurity doped at Sr or Ti cation sites. Moreover, the (Cr@Sr, B@O)-SrTiO 3 retains the charge balancing without the generation of unexpected oxygen vacancies, and is more desirable for solar light harvesting due to its higher absorption than others in the entire visible light. The findings can rationalize the available experimental results and are helpful in designing SrTiO 3 -based photocatalysts with high-efficiency performance.