Electronic and Optical Sensitivity of Aluminum-Doped Boron Phosphide Monolayers for DNA Base Detection: A First-Principles Study.

Genetic testing has become increasingly important for the early diagnosis of diseases, as it can significantly improve treatment success rates and patient survival. A new type of two-dimensional (2D) material, the boron phosphide (BP) monolayer, has recently been recognized as a semiconductor material with excellent electronic properties, high surface reactivity, and environmental friendliness. In this study, density functional theory (DFT) calculations are employed to investigate the adsorption behavior of nucleobases (A = Adenine, T = Thymine, C = Cytosine, G = Guanine) on an aluminum-doped BP monolayer (Al-doped BP). The optical sensitivity, electronic sensitivity, and work function of the material are also analyzed. The results demonstrate that the presence of aluminum enhances the adsorption ability of the BP monolayer, especially in the case of the adsorption of Adenine, which presents the highest adsorption energy of -2.27 eV. Additionally, the adsorption of Adenine on Al-doped BP shows remarkable optical sensitivity with significant changes, and both Adenine and Guanine exhibit the largest conductivity change on the Al-doped BP monolayer. These computational results contribute to a better understanding of the application mechanisms of aluminum-doped BP materials in detecting nucleobases. The findings indicate that the Al-doped BP monolayer demonstrates superior selectivity toward Adenine, making it a promising candidate for biosensor applications.