Intercalated architecture of Mg₂AlXY₅ monolayer with built-in potential difference and high-power-conversion...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Two-dimensional (2D) layered materials are crucial for 2D optoelectronic devices due to their stability and power-conversion efficiency.
• Centrosymmetric structures hinder photogenerated carrier separation, limiting device performance.

Purpose of the Study:

• To design novel non-centrosymmetric multi-atomic layer monolayers, Mg₂AlXY₅ (X = Ga, In; Y = S, Se, Te).
• To investigate their structural stability, electronic properties, and potential for optoelectronic applications.

Main Methods:

• First-principles calculations were employed to screen and analyze the proposed materials.
• Structural stability, band gaps, electron mobilities, and optical absorption spectra were evaluated.

Main Results:

• Mg₂AlXY₅ monolayers exhibit excellent structural stability and a built-in potential difference that enhances carrier separation.
• Most monolayers possess direct band gaps and high electron mobilities (up to ~10³ cm²V^-1s^-1), with optical absorption across the near-infrared to visible spectrum.
• Spin-orbit coupling induces a band gap transition in specific telluride monolayers.
• The Mg₂AlGaSe₅/InSe heterostructure shows a promising power conversion efficiency of 18.64%.

Conclusions:

• The designed Mg₂AlXY₅ materials are promising candidates for advanced 2D optoelectronic devices.
• Their inherent properties facilitate efficient photogenerated carrier separation and light absorption.
• The Mg₂AlGaSe₅/InSe heterostructure demonstrates significant potential for high-efficiency solar energy conversion.