Investigation and fine-tuning of optoelectrical features of tertiary aminophenyl-activated poly(1,3,4-oxadiazole) conjugated system

Abstract

A novel π-conjugated polymer with N-alkyl substituted side chains, viz. poly[(2-N,N′-dibutylaminophenyl)1,3,4-oxadiazole] (PNAPO), possessing tunable optoelectronic properties, has been synthesized and characterized. PNAPO exhibited good solubility, indicating its suitability for easy optoelectronic device fabrication. Flexible films of PNAPO have been fabricated by adopting a blending route using poly(methyl methacrylate) or polystyrene. The effect of PNAPO particle size reduction, in the nanoregion, on the optical characterization was evaluated by a re-precipitation strategy. PNAPO has been found to exhibit an emission wavelength in the region of 522–590 nm with good quantum yield, for different particle size dimensions. Interestingly, it has been observed to exhibit solvatochromism. Z-scan experiments, with Nd: YAG laser, reveal that PNAPO possesses a low optical limiting threshold value. Interestingly, it shows a low turn-on voltage (0.23 V), suitable for fabricating the active layers in optoelectronic devices. PNAPO has been found to be stable up to 240 °C. These results highlight the possible utilization of PNAPO as an emissive layer in optoelectronic devices and for nonlinear optical (NLO) processes. The graphical abstract represents the optical and electrical features of PNAPO. It indicates the structure of PNAPO. It shows the bright emissive property of PNAPO in the bluish green region of the electromagnetic radiation upon excitation with UV light. The light-emitting diode fabrication using PNAPO as an emissive layer is highlighted. A linear I–V characteristic of PNAPO has also been indicated through a current–voltage plot.