Deep blue light emitting Cyno-DPQ phosphor with large stokes shift and high thermal stability for OLEDs and display applications

Abstract

A deep blue light emitting organic phosphor namely, 2-(4-cynophenyl)-4 Phenyl quinoline (CN-DPQ) has been synthesized successfully by acid-catalyzed Friedlander reaction. The synthesized phosphor was characterized for its structural, thermal and optical properties. Fourier Transform Infrared (FTIR) spectra of CN-DPQ confirm the formation of the complex. Thermo gravimetric and differential thermal analysis (TGA/DTA) was employed to probe the thermal stability and melting point of the synthesized complex. Scanning electron microscopy (SEM) demonstrates the formation of agglomerated nano rods in CN-DPQ. Energy dispersive analysis of X-ray (EDAX) spectroscopy confirms the organic nature of the synthesized complex. UV–vis optical absorption spectra of CN-DPQ in different solvents illustrate two absorption bands in the range of 301–330nm. This spectrum was also employed to calculate the energy band gap (Eg) and oscillator strength (f) of solvated Cyno-DPQ. Photoluminescence (PL) spectra of CN-DPQ demonstrates emission in deep blue region of visible spectrum at 442nm in solid state with large stokes shift when excited at 385nm. CIE co-ordinates (0.1516, 0.045) with full width at half maximum (FWHM) value of 57nm were obtained for the synthesized organic phosphor. These parameters prove its applications in organic light-emitting diodes (OLEDs), light-emitting electrochemical cells and solid-state lighting and display applications.