Title Tert-butylcarbazole and methoxycarbazole substituted on the phenazine group exhibit mechano and thermoresponsivity for TADF LEECs
Authors Rabiei, Marzieh ; Hosseinnezhad, Mozhgan ; Ghahary, Raheleh ; Nutalapati, Venkatramaiah ; Nasiri, Sohrab ; Nunzi, Jean-Michel ; Padgurskas, Juozas ; Rukuiza, Raimundas
DOI 10.1021/acsaom.5c00065
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Is Part of ACS Applied optical materials.. Washington, DC : American Chemical Society. 2025, vol. 3, iss. 7, p. 1483-1498.. ISSN 2771-9855
Keywords [eng] phenazine ; tert-butylcarbazole ; methoxycarbazole ; mechanochromism ; thermochromism ; TADF ; LEECs
Abstract [eng] Two new well-defined donor–acceptor–donor (D–A–D′) thermally activated delayed fluorescence (TADF) molecules with mechanochromic and thermochromic architectures were designed and synthesized based on tert-butylcarbazole and methoxycarbazole substituents attached to a phenazine derivative. Density functional theory (DFT) studies revealed molecular structures with extended π-conjugation and low singlet–triplet energy gaps (ΔEST), which enhance reverse intersystem crossing (RISC) for efficient TADF. Single-crystal X-ray diffraction confirms differences in molecular packing. The dye composed of tert-butylcarbazole exhibits lower aggregation and higher photoluminescence quantum yield (PLQY) upon spin-coating in a solid film, owing to its bulkier structure. Thermal stability studies demonstrated high decomposition temperatures (Td > 300 °C) and improved rigidity of the dye consisting of tert-butylcarbazole. Photophysical investigations revealed that the dyes dispersed in a tetrahydrofuran (THF):water mixture showed aggregation-induced emission enhancement (AIEE). Incorporation of the complex organometallic [Ir(buoppy)2(dmapzpy)]PF6 as a host in LEECs favors the energy transfer and yields single emission peaks at 588 and 587 nm with 60 wt % host content. The improved device attains maximum current (28.97 cd A–1), power (22.11 lm W–1), and external quantum efficiency (4.02%). These findings underline the significance of substituent design and host:guest interactions in improving TADF LEEC performance and provide new insights for high-efficiency optoelectronic devices.
Published Washington, DC : American Chemical Society
Type Journal article
Language English
Publication date 2025
CC license CC license description