Experimental and theoretical investigation of tris-(8-hydroxy-quinolinate) aluminum (Alq3) photo degradation

We investigate the stability of tris-(8-hydroxyquinolinato) aluminum (Alq3) under UV photo degradation using a combination of experimental and theoretical techniques. Alq3 thin films were irradiated with He–Xe lamp discharges, as a function of the exposition time, at a wavelength λ = 307 nm. The irradiated and non-irradiated films were analyzed by Fourier transform infrared (FTIR) spectroscopy. The experimental FTIR spectrum of the exposed sample exhibits a band at 1697 cm−1, attributed to a carbonyl group. Theoretical calculations of Gibbs free energy and molecular vibrational properties for a variety of possible degradation products allow us to determine the most likely products and produce insight into the degradation mechanisms.