Dispelling the Myth of Passivated Codoping in TiO2

Benjamin A.D. Williamson; John Buckeridge; Nicholas P. Chadwick; Sanjayan Sathasivam; Claire J. Carmalt; Ivan P. Parkin; David O. Scanlon

doi:10.1021/acs.chemmater.9b00257

Dispelling the Myth of Passivated Codoping in TiO₂

Benjamin A.D. Williamson, John Buckeridge, Nicholas P. Chadwick, Sanjayan Sathasivam, Claire J. Carmalt, Ivan P. Parkin, David O. Scanlon^*

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

Modification of TiO₂ to increase its visible light activity and promote higher performance photocatalytic ability has become a key research goal for materials scientists in the past 2 decades. One of the most popular approaches proposed this as "passivated codoping", whereby an equal number of donor and acceptor dopants are introduced into the lattice, producing a charge neutral system with a reduced band gap. Using the archetypal codoping pairs of [Nb + N]- and [Ta + N]-doped anatase, we demonstrate using hybrid density functional theory that passivated codoping is not achievable in TiO₂. Our results indicate that the natural defect chemistry of the host system (in this case n-type anatase TiO₂) is dominant, and so concentration parity of dopant types is not achievable under any thermodynamic growth conditions. The implications of passivated codoping for band gap manipulation in general are discussed.

Original language	English
Pages (from-to)	2577-2589
Number of pages	13
Journal	Chemistry of Materials
Volume	31
Issue number	7
DOIs	https://doi.org/10.1021/acs.chemmater.9b00257
Publication status	Published - 9 Apr 2019

Bibliographical note

Funding Information:
This work made use of the ARCHER U.K. National Supercomputing Service (http://www.archer.ac.uk) via our membership of the U.K.’s HEC Materials Chemistry Consortium, which is also funded by the EPSRC (EP/ L000202). B.A.D.W. would like to acknowledge the use of the “bapt” python-package by A. Ganose (https://github.com/utf/ bapt) to plot the band alignment in Figure 6. The UCL Legion and Grace HPC Facilities (Legion@UCL and Grace@UCL) were also used in the completion of this work. D.O.S, C.J.C., and I.P.P. would like to acknowledge support from the EPSRC (EP/N01572X/1). D.O.S. acknowledges support from the European Research Council, ERC, (grant no. 758345). We are grateful to the U.K. Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1).

Publisher Copyright:
© 2019 American Chemical Society.

ASJC Scopus subject areas

General Chemistry
General Chemical Engineering
Materials Chemistry

Access to Document

10.1021/acs.chemmater.9b00257

Cite this

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title = "Dispelling the Myth of Passivated Codoping in TiO2",

abstract = "Modification of TiO2 to increase its visible light activity and promote higher performance photocatalytic ability has become a key research goal for materials scientists in the past 2 decades. One of the most popular approaches proposed this as {"}passivated codoping{"}, whereby an equal number of donor and acceptor dopants are introduced into the lattice, producing a charge neutral system with a reduced band gap. Using the archetypal codoping pairs of [Nb + N]- and [Ta + N]-doped anatase, we demonstrate using hybrid density functional theory that passivated codoping is not achievable in TiO2. Our results indicate that the natural defect chemistry of the host system (in this case n-type anatase TiO2) is dominant, and so concentration parity of dopant types is not achievable under any thermodynamic growth conditions. The implications of passivated codoping for band gap manipulation in general are discussed.",

author = "Williamson, {Benjamin A.D.} and John Buckeridge and Chadwick, {Nicholas P.} and Sanjayan Sathasivam and Carmalt, {Claire J.} and Parkin, {Ivan P.} and Scanlon, {David O.}",

note = "Funding Information: This work made use of the ARCHER U.K. National Supercomputing Service (http://www.archer.ac.uk) via our membership of the U.K.{\textquoteright}s HEC Materials Chemistry Consortium, which is also funded by the EPSRC (EP/ L000202). B.A.D.W. would like to acknowledge the use of the “bapt” python-package by A. Ganose (https://github.com/utf/ bapt) to plot the band alignment in Figure 6. The UCL Legion and Grace HPC Facilities (Legion@UCL and Grace@UCL) were also used in the completion of this work. D.O.S, C.J.C., and I.P.P. would like to acknowledge support from the EPSRC (EP/N01572X/1). D.O.S. acknowledges support from the European Research Council, ERC, (grant no. 758345). We are grateful to the U.K. Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1). Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",

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AU - Scanlon, David O.

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