Interface properties of CsPbBr$_3$ /CsPbI$_3$ perovskite heterostructure for solar cell

TL;DR

This study investigates the interface properties of CsPbBr$_3$/CsPbI$_3$ perovskite heterostructures using first-principles calculations, revealing structural and electronic features relevant for solar cell applications.

Contribution

It provides new insights into the atomic bonding, band structure, and optical properties of CsPbBr$_3$/CsPbI$_3$ heterostructures, highlighting their potential for solar energy devices.

Findings

Bond lengths of Cs-Br and Cs-I are approximately 4.106 Å and 3.922 Å.

Band gap differences are mainly due to I-5p and Br-4p orbital energies.

Iodine contributes more to absorption spectra in bilayer structures.

Abstract

We explore the interface properties of perovskite heterostructure CsPbBr$_3$/CsPbI$_3$ through first-principles calculations. The structural interface is formed by the bonding of Cs-Br and Cs-I with bond length of $\sim$4.106 and 3.922 \AA. The upshift of Goldsmith tolerance factor in the range $0.8<t<1$ from $t<0.8$ is revealed for the bi-layer interface, from bulk, reflecting the structural rearrangement from anisotropy to isotropy in confinement. The band gap arises mainly due to the energy difference of I-5p orbital than that of Br-4p at the valence band and Pb-6p at the conduction band. Heavier halide shows the red shift in the absorption spectra, for the pristine monolayer component. For the bilayer geometry, iodine contribution is more observed than that of bromine and the underlying interface properties may be useful for solar cell devices application.