Cesium-Magnesium based cubic halide perovskites CsMgX3 (X = Cl,Br) with
engrossing thermoelectric and optical properties suitable for energy
conversion and solar cell based applications: A DFT speculation
Abstract
We have performed a study on two cubic structured halide perovskites,
CsMgX3 (X = Cl, Br) using ab-initio simulations in the outline of
density functional theory. In this context, we extensively explored
their structural, electronic, thermoelectric and optical properties. The
cubic phases of these compounds were optimized and were found to be
stable and energetically feasible. Their band structures implied that
they are indirect wide gap semiconductors with band gaps of 6.35 and
4.26 eV for CsMgCl3 and CsMgBr3 respectively. Further, their
thermoelectric properties comprised of high Seebeck coefficient and
electrical conductivities with p-type as the majority charge carriers.
Also their high figure of merit (ZT) of values 0.69 and 0.75 at room
temperature, showed their efficient thermoelectric response along with
the potential to be used for power generation and energy conversion
applications. The wide band gaps and their optical behavior consisting
of zero absorption, electron energy loss and negligible reflectance in
visible region signified a important possibility to use these compounds
as hole transport materials (HTM) in the solar cells, which can augment
the efficiency of solar cell to a huge level. Moreover, the other
calculated optical properties showed contrasting behavior in varying
ranges of the electromagnetic spectrum. Thus, we speculate that the
studied halide perovskites can emerge as very useful materials for
thermoelectric energy conversion and solar cell applications.