Thermally Activated Delayed Fluorescence of Dibenzophenazine-Cored Phenazaborines in Solid State: Anion Modulation of Photophysics

The relentless pursuit of high-performance organic light-emitting diodes (OLEDs) necessitates the exploration of novel materials with efficient light emission. Herein, we report donor–acceptor–donor (D–A–D) compounds, incorporating dibenzo[a,j]phenazine (DBPHZ) as the acceptor (A) and phenazaborine (PAzB) derivatives as the donors (D), embedded in various hosts, and investigate their impact on emission mechanisms. This study examines the effect of strategic fluorination of the trivalent boron center on the performance of the D–A–D compounds as solid-state emitters. The incorporation of fluoride into the D–A–D compounds within the matrix films resulted in a red shift in the photoluminescence (PL) emission. Additionally, we evaluated the influence of fluoride addition on the delayed emission characteristics of the D–A–D-containing films. This solid-state modulation technique demonstrated a potential applicability to OLEDs. Quantum chemical calculations elucidated how fluoride incorporation alters the photophysical properties of the compounds by modifying the electronic characteristics of the excited states.