A study of the optical band gap of zinc phthalocyanine nanoparticles using UV-Vis spectroscopy and DFT function

In the present work, we used the ultraviolet-Visible (UV-Vis) spectroscopy technique to find the optical band gap of zinc phthalocyanine nanoparticles (ZnPcNP) experimentally. Moreover, we used a time-dependent density functional theory (TDDFT) to simulate the UV-Vis absorption spectrum of ZnPc molecule in gas and solution phases. The ZnPc-NP absorption spectrum shows a shift toward higher energies compared to the bulk ZnPc. The simulated UV-Vis and the experimental nanoparticle's spectrum were found to have a good agreement. The ZnPc energy band gap from the DFT calculations shows how it's possible to get wider range of energy band gap for the ZnPc. The ZnPc-NP's size and shape were examined using the transmission electron microscope (TEM).