Diphenylimidazole Based Fluorophores for Explosive Chemosensors and as Efficient Host Materials for Green Phosphorescent Organic Light Emitting Diodes
Sandhya Rani Nayak, Iram Siddiqui, Shahnawaz Shahnawaz, Jwo‐Huei Jou, Sivakumar Vaidyanathan
Abstract
Efficient near-ultraviolet light-emitting materials are pivotal for organic light-emitting devices (OLEDs) because of their long lifetime and energy savings for high-quality flat panel displays. In this study, a series of luminophores having electron-donating and electron-withdrawing groups with N1 functionalization were designed that can act as host and chemosensor. All TPTI luminophores show deep blue emission in the respective phase (solution, thin film, and solid) with reasonable quantum yield. Electrochemical analysis and theoretical calculations show a similar trend for HOMO–LUMO energy gap calculations, and all of them have high triplet energies (2.76–2.91 eV). High triplet energies of the TPTI luminophores are extensively applied for green (Ir(ppy)3 2.4 eV) emitting materials. It has been observed that the host TPTI-1 possesses the highest efficiency and luminance among all four hosts in all respects at 15.0 wt % with a maximum power efficacy (PEmax) of 24.0 lm W–1, a maximum current efficacy (CEmax) of 38.2 cd A–1, and a maximum external quantum efficiency (EQEmax) of 6.8% with a maximum luminance of 7549 cd m–2 at a turn-on voltage of 4.4 V. With their structural functionality, the TPTI luminophores were used for the recognition of nitro aromatic compounds (including picric acid (PA)). All the luminophores showed good selectivity and high catching toward the PA, and the sensing mechanism was thoroughly investigated theoretically and experimentally.