Title From donor-donor exciplex-forming interfaces to detection of an explosive compound with phenylethenyl derivatives redefining OLED efficiency and extremely high sensitivity to picric acid
Authors Rashid, Ehsan Ullah ; Cekaviciute, Monika ; Simokaitiene, Jūratė ; Ghasemi, Melika ; Volyniuk, Dmytro ; Ivaniuk, Khrystyna ; Stakhira, Pavlo ; Grazulevicius, Juozas Vidas
DOI 10.1021/acsaelm.5c00123
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Is Part of ACS Applied electronic materials.. Washington, DC : American Chemical Society. 2025, vol. 7, iss. 9, p. 3877-3891.. ISSN 2637-6113
Keywords [eng] aggregation-induced emission enhancement ; doping-free organic light-emitting diode ; exciplex ; phenothiazine ; phenoxazine ; picric acid sensing ; tetraphenylethylene
Abstract [eng] In this study, three derivatives of phenylethenyl-substituted phenoxazine and phenothiazine are synthesized via Buchwald-Hartwig cross-coupling, targeting multifunctionality as exciplex-forming materials and efficient cyan emitters for organic light-emitting diodes (OLEDs) and sensitive dectectors of picric acid. Advanced density functional theory (DFT) calculations at the mPW1PW91/6-31G(d,p) level unveil the intricate electronic architectures of these compounds, emphasizing their spatial molecular orbitals and the charge-transfer dynamics governing excited-state properties. Reorganization energy calculations indicate superior hole mobility, particularly for derivatives with tetraphenylethenyl groups. Photophysical investigations reveal aggregation-induced emission enhancement (AIEE) in water-THF mixtures, with cyan fluorescence intensifying at high water fractions (fw% = 99) due to the formation of emissive aggregates. Photoluminescence quantum yields (PLQYs) are significantly higher of solid films (13.5-53%) compared to those of dilute toluene solutions (3-26%). This observation is attributed to enhanced intermolecular interactions and aggregate formation. The emissive aggregates of the compounds exhibit extremely high sensitivity to electron-deficient picric acid via noncovalent interactions with Stern-Volmer constants up to 2.96 × 104 M-1. This is attributed to their strong donor-acceptor charge-transfer mechanisms. OLEDs employing these materials as emitters display bluish-cyan electroluminescence (λmax≈500 nm), with brightness surpassing 1000 cd/m2 and external quantum efficiencies (EQEs) ranging from 2.5 to 6%. The relatively high EQEs are explained by triplet harvesting from interface donor-donor exciplexes.
Published Washington, DC : American Chemical Society
Type Journal article
Language English
Publication date 2025
CC license CC license description