Title Ornamenting of blue thermally activated delayed fluorescence emitters by anchor groups for the minimization of solid-state solvation and conformation disorder corollaries in non-doped and doped organic light-emitting diodes /
Authors Mahmoudi, Malek ; Gudeika, Dalius ; Kutsiy, Stepan ; Simokaitiene, Jurate ; Butkute, Rita ; Skhirtladze, Levani ; Woon, Kai Lin ; Volyniuk, Dmytro ; Grazulevicius, Juozas Vidas
DOI 10.1021/acsami.2c12475
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Is Part of ACS applied materials & interfaces.. NW, Washington, DC : American chemical society. 2022, vol. 14, iss. 35, p. 40158-40172.. ISSN 1944-8244. eISSN 1944-8252
Keywords [eng] acceptor ; blue TADF ; donor ; organic light-emitting diodes ; tert-butyl carbazole ; trifluoromethyl group
Abstract [eng] Motivated to minimize the effects of solid-state solvation and conformation disorder on emission properties of donor-acceptor-type emitters, we developed five new asymmetric multiple donor-acceptor type derivatives of tert-butyl carbazole and trifluoromethyl benzene exploiting different electron-accepting anchoring groups. Using this design strategy, for a compound containing four di-tert-butyl carbazole units as donors as well as 5-methyl pyrimidine and trifluoromethyl acceptor moieties, small singlet-triplet splitting of ca. 0.03 eV, reverse intersystem crossing rate of 1 × 106 s-1, and high photoluminescence quantum yield of neat film of ca. 75% were achieved. This compound was also characterized by the high value of hole and electron mobilities of 8.9 × 10-4 and 5.8 × 10-4 cm2 V-1 s-1 at an electric field of 4.7 × 105 V/cm, showing relatively good hole/electron balance, respectively. Due to the lowest conformational disorder and solid-state solvation effects, this compound demonstrated very similar emission properties (emission colors) in non-doped and differently doped organic light-emitting diodes (OLEDs). The lowest conformational disorder was observed for the compound with the additional accepting moiety inducing steric hindrance, limiting donor-acceptor dihedral rotational freedom. It can be exploited in the multi-donor-acceptor approach, increasing the efficiency. Using an emitter exhibiting the minimized solid-state solvation and conformation disorder effects, the sky blue OLED with the emitting layer of this compound dispersed in host 1,3-bis(N-carbazolyl)benzene displayed an emission peak at 477 nm, high brightness over 39 000 cd/m2, and external quantum efficiency up to 15.9% along with a maximum current efficiency of 42.6 cd/A and a maximum power efficiency of 24.1 lm/W.
Published NW, Washington, DC : American chemical society
Type Journal article
Language English
Publication date 2022
CC license CC license description