Design, fabrication and optical characterizations of pyrimidine fused quinolone carboxylate moiety for photodiode applications

Abstract

A novel ethyl 3-amino-2-cyano-6-hydroxy-7, 12-dioxo-2, 7, 12, 12a-tetrahydro-1H-benzo[g]pyrimido[1, 2-a]quinoline-5-carboxylate(3ABPQC)was synthesized by treating ethyl 2-amino-4-hydroxy-5, 10-dioxo-1, 5, 10, 10a-tetrahydrobenzo [g]quinoline-3-carboxylate 1 with methylidene malononitrile(2). Thin films of ABPQC were prepared to utilize thermal evaporation technique at room temperature under a certain condition for obtaining a high-quality film. The molecular, structural, and morphological characterizations were employed using Fourier transform IR, X-ray diffraction, and scanning electron microscopy. The analysis proved two available band gaps of 1.51 and 3.55 eV for the onset and optical gaps, respectively. The experimental optical gap was compared with those obtained using density functional theory (DFT). The spectral dependence of refractive index was explained based on single oscillator model and the main important parameters were extracted using the formula of Wemple and DiDomenico and found to be 2.91, 4.97, 0.34 and 0.21 for the oscillator energy, E0, dispersion energy, Ed, and the rth moments, M-1 and M-3, respectively. The remarkable optical behavior with the unique optical response representations of ABPQC allows designing and manufacturing organic- photodiodes based on ABPQC nanostructured films.