A DFT Study of Optoelectronic and Photo-catalytic Properties in 2D Copper and Silver Halides Through Strain Engineering

Abstract

The results show that all the studied semiconductors have
indirect bandgap while under the strain of (−8% to +8%), the bandgap has changed differently.
Projected density of states revealed that CBM and VBM are mainly contributed by p-orbital and
d-orbital of Cu-atom respectively in the case of all Copper halides (CuCl, CuBr, and CuI). Similarly,
in the case of Silver halides (AgCl, AgBr, and AgI) CBM and VBM are mainly contributed by p-
orbital and d-orbital of Ag-atom respectively. Phonon band structures of all unstrained monolayers
are thermodynamically stable. The computed real part ε 1 (ω) and the imaginary part ε 2 (ω) of
dielectric function revealed that CuCl and CuBr are suitable for the development of devices that
may work in the infrared range while other materials such as CuI, AgCl, AgBr, and AgI are suitable
for the development of devices that may work in the visible range. Both
E V BM and E CBM in CuCl, CuBr, CuI, AgCl, and AgBr (ML) attain favorable positions that’s
why these materials are appropriate for water splitting at pH=0 while AgI (ML) is suitable for the
reduction of water but not for oxidati