Thermally Activated\nDelayed Fluorescence of Dibenzophenazine-Cored\nPhenazaborines in Solid State: Anion Modulation of Photophysics

The relentless pursuit of high-performance organic light-emitting\ndiodes (OLEDs) necessitates the exploration of novel materials with\nefficient light emission. Herein, we report donor–acceptor–donor\n(D–A–D) compounds, incorporating dibenzo[<i>a,j</i>]phenazine (DBPHZ) as the acceptor (A) and phenazaborine (PAzB) derivatives\nas the donors (D), embedded in various hosts, and investigate their\nimpact on emission mechanisms. This study examines the effect of strategic\nfluorination of the trivalent boron center on the performance of the\nD–A–D compounds as solid-state emitters. The incorporation\nof fluoride into the D–A–D compounds within the matrix\nfilms resulted in a red shift in the photoluminescence (PL) emission.\nAdditionally, we evaluated the influence of fluoride addition on the\ndelayed emission characteristics of the D–A–D-containing\nfilms. This solid-state modulation technique demonstrated a potential\napplicability to OLEDs. Quantum chemical calculations elucidated how\nfluoride incorporation alters the photophysical properties of the\ncompounds by modifying the electronic characteristics of the excited\nstates.