Optical and electrical properties of new NLO active ethynylated chalcone as solution-processed OLEDs material: Experimental and theoretical approaches

Abstract

This present study investigated the contribution of new hybrid moieties of ethynylated (C≡C) and chalcone (–CO–CHCH-) units as nonlinear optically active and successfully applied to solution-processed OLEDs material. The simulated data from Density Functional Theory (DFT) indicates that 3-(pyren-1-yl)-1-((4-phenylethylyn)phenyl)-2-propen-1-one (MM-1a) reveals good polarizability properties of total first hyperpolarizability βtot at 842.32 × 10−30 esu associated with low HOMO-LUMO gap at 3.04 eV. The structure-property relationship also was highlighted using TD-DFT calculations for frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) maps and global chemical reactivity descriptors (GCRD). The photophysical behaviours of MM-1a presented emission maxima at 520 nm with large Stokes shifts at 95 nm where this emission shows fluoresce characters and intramolecular charge transfer (ICT) state. Remarkably, a response from the open and closed aperture Z-scan analysis reveals that MM-1a displays reverse saturable absorption (RSA) performance and self-defocusing effects under 532 nm continuous wave (CW) laser. Further, solution-processed OLED featuring single-layer of ITO/PEDOT:PSS/MM-1a/Au displayed electroluminescence effect by intense yellow emission obtained under direct current (DC) voltages supply. From the obtained result, the introduction of ethynyl as spacer in chalcone system facilitated intramolecular charge transfer and finely tuned the electronic properties to enhance NLO response and promising emissive layer for OLED applications.