First-principles calculations of monolayered Al2Te5: a promising 2D donor semiconductor with ultrahigh visible light harvesting

Atomically thin two-dimensional (2D) crystals have piqued the curiosity of researchers due to their unique features and potential applications, such as catalysis and ion batteries. One essential and desirable aspect of 2D materials is that they have a large photoreactive contact surface for optical absorption. Here, a 2D crystal is proposed that possesses a moderate adjustable indirect band gap of 1.95 eV (HSE06) and exhibits ultrahigh visible light harvesting with a absorption coefficient of up to 10(8) cm(-1) in the similar to 380 to 800 nm range of the visible light spectrum. Besides that, the indirect band gap can be converted to a direct one under biaxial strain. By means of density functional theory, the 2D Al2Te5 monolayer displays great stability and promise of experimental fabrication. These advantages will provide considerable application potential for future photovoltaics (PV) devices.

Automated summary

By using density functional theory, researchers have discovered a two-dimensional crystal Al2Te5 monolayer with a small adjustable indirect band gap, which exhibits strong light absorption performance in the visible light spectrum, with an absorption coefficient of 10(8) cm(-1). In addition, the indirect band gap can be converted to a direct one under biaxial strain. These advantages provide important possibilities for future applications in photovoltaic devices.