Premium
Improved Photoactivity of Pyroxene Silicates by Cation Substitutions
Author(s) -
Legesse Merid,
Park Heesoo,
El Mellouhi Fedwa,
Rashkeev Sergey N.,
Kais Sabre,
Alharbi Fahhad H.
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201701155
Subject(s) - pyroxene , electronegativity , band gap , materials science , chemistry , mineralogy , optoelectronics , olivine , organic chemistry
We investigated the possibility of band structure engineering of pyroxene silicates with chemical formula A +1 B +3 Si 2 O 6 by proper cation substitution. Typically, band gaps of naturally formed pyroxene silicates such as NaAlSi 2 O 6 are quite high (≈5 eV). Therefore, it is important to find a way to reduce band gaps for these materials below 3 eV to make them usable for optoelectronic applications operating at visible light range of the spectrum. Using first‐principles calculations, we found that appropriate substitutions of both A + and B 3+ cations can reduce the band gaps of these materials to as low as 1.31 eV. We also discuss how the band gap in this class of materials is affected by cation radii, electronegativity of constituent elements, spin‐orbit coupling, and structural modifications. In particular, the replacement of Al 3+ in NaAlSi 2 O 6 by another trivalent cation Tl 3+ results in the largest band‐gap reduction and emergence of intermediate bands. We also found that all considered materials are still thermodynamically stable. This work provides a design approach for new environmentally benign and abundant materials for use in photovoltaics and optoelectronic devices.