Investigation of the structural, electronic and optical properties of C9H17NO2 phases with promising potential for optoelectronic devices

Abstract

Gabapentin (C₉H₁₇NO₂) is a small organic molecule known for its pharmaceutical use, but in its solid-state crystalline forms, it exhibits promising structural and optoelectronic properties. In this work, we employed density functional theory (DFT) to investigate the structural, electronic, and optical properties of three anhydrous polymorphs (α, β, and γ) of gabapentin. The calculated band gaps for the α, β, and γ polymorphs of C₉H₁₇NO₂ were found to be 4.73 eV, 4.55 eV, and 4.37 eV, respectively, based on GGA-PBE. To improve the accuracy, we also used the mBJ-GGA method, which yielded band gaps of 5.5 eV, 5.1 eV, and 5.9 eV, respectively, and these values indicated that all the three phases absorb in the ultraviolet (UV) region. Additionally, the static dielectric constants were calculated to be 2.64, 2.57, and 2.40, respectively, confirming their excellent insulating properties. These results highlight the potential of gabapentin polymorphs for UV optoelectronic applications such as UV detectors, reflective coatings, and high-frequency insulators.