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

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 301-330 nm. 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 442 nm in solid state with large stokes shift when excited at 385 nm. CIE co-ordinates (0.1516, 0.045) with full width at half maximum (FWHM) value of 57 nm 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.