Influence of Hydrogen Impurity on the ZnSb2O6 Transparent Conductive Oxide (TCO) Used in Solar Cells

Transparent conductive oxides (TCOs) are, today, essential components of modern solar cells, display technology, and optoelectronic devices. The new synthesized ZnSb2O6 is used as a transparent electrode with electron affinity (EA) greater than most of the used TCOs, giving it great implications for organic and perovskite solar cells. It is well established that some unintentional impurities can greatly alter the electrical and optical properties of TCOs. One of these defects is hydrogen, as it is ubiquitous and very difficult to remove from the synthesized material. In this study, we use density functional theory (DFT) interfaced with the genetic algorithm (GA) to explore the influence of the hydrogen impurity on the physical properties of the new transparent conducting oxide, ZnSb2O6. Due to this metal oxide’s structural and chemical complexity, the stable site for the H atoms is not trivial. Thus, we use the genetic algorithm to explore the preferred position for hydrogen impurity due to the complexity of the search space for its position. Also, to study its influence on the host’s structural, electronic, and electrical properties, we use ab-initio simulation. The H atom prefers to occupy the anti-bonding site forming an angle of 96.55° with the nearest Sb–O bond. The n-type conductivity of the H-doped ZnSb2O6 is confirmed through the DOS plot. The obtained results can guide experimenters in the fabrication of high-performance and low-cost TCOs based on ZnSb2O6.