Accurate structural descriptor enabled screening for nitrogen and oxygen vacancy codoped TiO2 with a large bandgap narrowing

Nitrogen (N) doping has been widely adopted to improve the light absorption of TiO 2 . However, the newly introduced N-2 p states are largely localized thus barely overlap with O-2 p states in the valence band of TiO 2 , resulting in a shoulder-like absorption edge. To realize an apparent overlap between N-2 p and O-2 p states, charge compensation between N 3 - and O 2 - via electron transfer from oxygen vacancies (V O ) to N dopants is one possible strategy. To verify this, in numerous doping configurations of N/V O -codoped anatase TiO 2 , we identified two types of V O position independent N-dopant spatial orderings by efficient screening enabled with a newly designed structural descriptor. Compared with others, these two types of the N-dopant spatial orderings are highly beneficial for charge compensation to produce an apparent overlap between N-2 p and O-2 p states, therefore achieving a large bandgap narrowing. Furthermore, the two types of the N-dopant spatial orderings can also be generalized to N/V O -codoped rutile TiO 2 for bandgap narrowing. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.