Glass-forming derivatives of 2-cyano-2-(4H-pyran-4-ylidene) acetate for light-amplification systems

Abstract

A series of 2-cyano-2-(4H-pyran-4-ylidene) acetate derivatives with triphenyl and 9H-carbazole moieties were synthesized and investigated, mostly for potential applications in organic solid state lasers. Synthesized compounds show remarkable amorphous film formation ability, tunable thermal properties (thermal stability varies from 190 °C to 387 °C and glass transition temperature from 94 °C up to 141 °C) with light absorption from 400 nm to 600 nm and photoluminescence from 600 nm up to 800 nm. Dyes with incorporated mono-styryl- electron donating fragment (KTB, KTBC and KTB3K) showed higher photoluminescence quantum yield (PLQY) (from 16% up to 23%), significantly lower amplified spontaneous emission (ASE) excitation threshold values (24–52 μJ/cm2) in pure thin films comparing to bis-styryl- electron donating fragment containing molecules (Bis-K4C, Bis-K5C and Bis-K4CK) with PLQY of 5–7% and ASE excitation threshold between 165 and 223 μJ/cm2. Some of the investigated KTB-type laser dyes could be perspective materials for organic lasers as well as for laser technology investigation and applications.