MOCA as a dual-function organic semiconductor: Theoretical insights into photoresponsive bandgap engineering and nonlinear optics

ElMansy, Mohamed

doi:10.22034/crl.2026.572300.1776

MOCA as a dual-function organic semiconductor: Theoretical insights into photoresponsive bandgap engineering and nonlinear optics

Document Type : Research Article

Author

Mohamed ElMansy

Department of Physics, College of Science, Qassim University, Qassim, Buraydah 51452, Saudi Arabia

https://doi.org/10.22034/crl.2026.572300.1776

Abstract

This research presents the first theoretical investigation of 5-methyl-2-oxo-1,3-oxazolidine-4-carboxylic acid (MOCA) using Density Functional Theory (DFT) at the B3LYP/6-311G(d,p) level. The primary objective is to explore MOCA’s structural, electronic, and nonlinear optical (NLO) properties, with emphasis on its response to UV illumination. Geometry optimization reveals a stable molecular framework, while Frontier Molecular Orbital (FMO) analysis demonstrates a significant reduction in the HOMO-LUMO energy gap upon UV exposure—from 4.66 eV in the ground state to 2.09–2.22 eV in the excited triplet state—indicating enhanced charge transport characteristics suitable for use as a window layer in photovoltaic devices. Furthermore, computed polarizability and first-order hyperpolarizability (βtot) values show strong NLO activity; βtot decreases from 4.41 × 10⁻³⁰ esu before UV to 3.66 × 10⁻³⁰ esu after irradiation, yet remains substantially higher than urea (0.3728 × 10⁻³⁰ esu), highlighting MOCA’s potential for applications in frequency doubling, optical switching, and electro-optic modulation. The observed photoresponsiveness suggests avenues for developing smart, tunable photonic materials. This work provides foundational computational data for MOCA, filling a critical gap in the literature and paving the way for future experimental validation.

Graphical Abstract