902518-11-0Relevant articles and documents
Modulation of the Physicochemical Properties of Donor–Spiro–Acceptor Derivatives through Donor Unit Planarisation: Phenylacridine versus Indoloacridine—New Hosts for Green and Blue Phosphorescent Organic Light-Emitting Diodes (PhOLEDs)
Thiery, Sébastien,Tondelier, Denis,Geffroy, Bernard,Jeannin, Olivier,Rault-Berthelot, Jo?lle,Poriel, Cyril
, p. 10136 - 10149 (2016)
This work reports a detailed structure–property relationship study of a series of efficient host materials based on the donor–spiro–acceptor (D-spiro-A) design for green and sky-blue phosphorescent organic light-emitting diodes (PhOLEDs). The electronic and physical effects of the indoloacridine (IA) fragment connected through a spiro bridge to different acceptor units, namely, fluorene, dioxothioxanthene or diazafluorene moiety, have been investigated in depth. The resulting host materials have been easily synthesised through short, efficient, low-cost, and highly adaptable synthetic routes by using common intermediates. The dyes possess a very high triplet energy (ET) and tuneable HOMO/LUMO levels, depending on the strength of the donor/acceptor combination. The peculiar electrochemical and optical properties of the IA moiety have been investigated though a fine comparison with their phenylacridine counterparts to study the influence of planarisation. Finally, these molecules have been incorporated as hosts in green and sky-blue PhOLEDs. For the derivative SIA-TXO2as a host, external quantum efficiencies as high as 23 and 14 % have been obtained for green and sky-blue PhOLEDs, respectively.
Spiro?type TADF emitters based on acridine donors and anthracenone acceptor
Hong, Jong-In,Huh, Jin-Suk,Yang, Dongwook
, (2021/10/27)
Two rigid spiro-type TADF emitters (CBZANQ, PXZANQ) were designed and synthesized via a two-step route. CBZANQ and PXZANQ both contain an anthracenone acceptor along with a carbazole?acridine-fused donor and a phenoxazine?acridine-fused donor, respectively, where each donor and acceptor are linked by a spiro bridge to form D-σ-A structures with an orthogonal arrangement. Both CBZANQ and PXZANQ have the difference between the singlet and triplet energy values (ΔEST) of 0.05 eV and 0.03 eV, respectively, which are sufficiently small for efficient triplet harvesting. CBZANQ with a weak electron donor (carbazole) exhibited a weak intramolecular charge transfer (ICT) character, resulting in a low photoluminescence quantum yield (PLQY) of 18%. On the other hand, when combined with a strong electron donor (phenoxazine), PXZANQ exhibited a strong ICT character, resulting in a high PLQY of 71%. Organic light-emitting diode (OLED) devices based on CBZANQ emitter and bis[2-(diphenylphosphino)phenyl] ether oxide (DPEPO) host exhibited sky-blue electroluminescence (EL) at 492 nm with a low external quantum efficiency (EQE) of 6.7%. Conversely, the OLED devices fabricated using PXZANQ emitter and DPEPO host exhibited green emission at 528 nm, along with a high EQE of 22.1%. Additionally, the efficiency of PXZANQ-based devices remained high at high luminance, indicating relatively small efficiency roll-off (13.9% EQE under 500 cd/m2).
Efficient organic light-emitting diodes based on iridium(iii) complexes containing indolo[3,2,1-jk]carbazole derivatives with narrow emission bandwidths and low efficiency roll-offs
Liao, Xiang-Ji,Lu, Jun-Jian,Luo, Xu-Feng,Yan, Zhi-Ping,Yuan, Li,Zhang, Yi-Pin,Zheng, You-Xuan,Zhu, Jin-Jun
, p. 8226 - 8232 (2021/07/13)
In this work, two cyclometalated ligands 2-(pyridin-2-yl)indolo[3,2,1-jk]carbazole (pyidcz) and 2-(4-(trifluoromethyl)pyridin-2-yl)indolo[3,2,1-jk]carbazole (tfpyidcz) containing an indolo[3,2,1-jk]carbazole unit were synthesized for achieving highly efficient iridium(iii) complexes (pyidcz)2Ir(tmd) and (tfpyidcz)2Ir(tmd) (tmd = 2,2,6,6-tetramethyl-3,5-heptanedione). The two Ir(iii) complexes exhibit emissions peaking at 499 and 554 nm, respectively, with narrow full width at half maximum (FWHM) values of 35 and 53 nm, respectively, short phosphorescence lifetimes less than 1 μs and high photoluminescence quantum yields of up to 90% in CH2Cl2solution. The organic light-emitting diodes (OLEDs) with (pyidcz)2Ir(tmd) and (tfpyidcz)2Ir(tmd) emitters show good performances. The (pyidcz)2Ir(tmd)-based device shows a turn-on voltage (Von) of 3.6 V with a maximum brightness (Lmax) of 39123 cd m?2, a maximum current efficiency (ηc,max) of 69.2 cd A?1, a maximum power efficiency (ηp,max) of 36.8 lm W?1and a maximum external quantum efficiency (EQEmax) of 21.2%. In particular, the FWHM bandwidth of the electroluminescence spectrum is only 33 nm, which was rarely reported for Ir(iii) complex-based OLEDs. The performance of the (tfpyidcz)2Ir(tmd)-based device is slightly better with aVonof 3.3 V, aLmaxof 31714 cd m?2, aηc,maxof 78.4 cd A?1, aηp,maxof 54.7 lm W?1and an EQEmaxof 24.0%. Furthermore, the efficiency roll-offs of both devices are small, and theηcvalues at 10?000 cd m?2brightness are still maintained at 60.0 and 71.4 cd A?1, respectively, which provide a powerful reference for developing indolo[3,2,1-jk]carbazole-based Ir(iii) complexes for efficient OLEDs.
