Investigation of the effects of light sources on the optoelectronic properties of pain relievers

In this thesis, the optoelectronic properties of three widely used analgesic drugs—Paracetamol (Parol), Ibuprofen, and Morphine—were systematically and comparatively investigated. Solutions of the drugs were prepared and optical measurements were carried out both without UV irradiation and under UV light sources with wavelengths of 254 nm, 365 nm, and 400 nm. Absorbance and transmittance spectra were recorded in the UV–visible region, and the optical band gaps were determined using the Tauc method. The results clearly demonstrate that all three drugs exhibit direct allowed electronic transitions and behave as wide band gap organic semiconductor-like materials. Refractive index analyses revealed pronounced normal and anomalous dispersion regions, while UV irradiation led to a reduction in maximum refractive index values and shifts in resonance frequencies. These findings indicate that UV irradiation induces significant modifications in the electronic structure and light–matter interaction mechanisms of the investigated drugs. The results suggest that Paracetamol, Ibuprofen, and Morphine can be considered not only as pharmaceutical compounds but also as UV-sensitive functional organic materials with potential applications in optoelectronic devices, biomedical photonics, UV sensors, and optical dosimetry systems.