Design and characterization of novel 2D TlPt2X3 (X = S, Se, Te) semiconductor monolayers for electronic and optoelectronic applications

The energy crisis and environmental issues have stimulated an increasing interest in developing novel materials, such as two-dimensional (2D) materials, with customized photocatalytic and photovoltaic features for sustainable energy production. In this study, we thoroughly investigated the stability, physical characteristics, electronic properties, optical behaviors, and photocatalytic potential of TlPt2X3 (X = S, Se, Te) monolayers (MLs) using state-of-the-art density functional theory calculations at HSE06 and PBE-GGA levels of theory. Our calculations show that these MLs are dynamically, thermally, mechanically, and thermodynamically stable. The elastic constant calculations indicate that these MLs possess high mechanical flexibility owing to their small Young's modulus. The HSE06 approach calculations reveal that the TlPt2S3, TlPt2Se3, and TlPt2Te3 MLs possess band gaps of 1.364 eV (indirect), 1.896 eV (indirect), and 1.174 eV (direct), respectively. The optical characteristics of these MLs demonstrate a wide absorption spectrum that can be activated by visible light, with considerable absorption intensity in the near ultraviolet range. Our findings demonstrate that the TlPt2Se3 (TlPt2Te3) ML exhibits remarkable hydrogen-oxygen (oxygen) evolution performance with an increase (decrease) in pH value, suggesting they can be used for photocatalytic water splitting under visible light. These results provide new directions for the use of these materials in photocatalytic water splitting and optical devices. [Display omitted] •Novel 2D-TlPt2X3 semiconducting materials whose layered bulk parent was experimentally synthesized are designed.•2D-TlPt2X3 monolayers are dynamically, mechanically and thermodynamically stable.•2D-TlPt2X3 monolayers are highly mechanical flexibility.•TlPt2S3 and TlPt2Se3 have indirect band gaps while TlPt2Te3 has direct band gap.•TTlPt2Se3 (TlPt2Te3) exhibits remarkable potential for application in solar water splitting.