Highly efficient non-doped blue organic light emitting diodes based on a D–π–A chromophore with different donor moieties

Abstract

The non-doped OLED based on MPPIS-Cz exhibits blue emission with CIE of (0.16, 0.08), maximum current and external quantum efficiency of 1.52 cd A−1 and of 1.42%, respectively.

Recent progress in imidazole based efficient near ultraviolet/blue hybridized local charge transfer (HLCT) characteristic fluorophores for organic light-emitting diodes

“…21). 127 The non-doped OLED based on the MPPIS-Cz 78 fluorophore showed blue EL emission with CIEs of (0.16, 0.08) and maximum efficiencies of a CE of 1.52 cd A À1 and an EQE of 1.42% (Table 8). However, the device efficiency is low as compared to Cz-BPIS 76 but the device based on the MPPIS-Cz 78 fluorophore showed deeper blue EL emission.…”

“…Researchers have used the styryl moiety as a spacer in the design strategy of the molecular structure, and it will increase the twisting nature of the molecules, and more twisting nature of the molecules push emission toward lower wavelength, due to restricting p-conjugation in the molecules. [126][127][128][129] In 2017, V. Thanikachalam et al designed and synthesized three blueemitting fluorophores, TPA-BDIS 74, TPA-BPIS 75, and Cz-BPIS 76, by connecting donor TPA/Cz and acceptor BI/PI through the styryl as a spacer (Fig. 21).…”

Rational design of hybridized local and charge transfer emitters towards deep blue emission by incorporating extra cyano-based acceptor moieties

“…11,12 Conversely, hybridized local and charge transfer (HLCT) type emitters have a short excitation lifetime, which is conducive to the manufacture of inexpensive and efficient non-doped OLEDs. [13][14][15] Similar to the TADF mechanism, HLCT materials achieve full utilization of excitons through high-lying reverse intersystem crossing (hRISC) between the high trilinear state T n (n Z 2) and the singlet state S m (m Z 1). [16][17][18][19] The charge transfer (CT) excited state component of the HLCT excited state facilitates an efficient RISC process, characterized by a smaller energy gap between T n and S m , resulting in higher EUE.…”

Benzoxazole-Based Hybridized Local and Charge-Transfer Deep-Blue Emitters for Solution-Processable Organic Light-Emitting Diodes and the In fluences of Hexahydrophthalimido

“…Based on the HLCT strategy, many HLCT blue materials have been developed. − Most of them are developed from imidazole, such as 1,2-diphenyl-1H-phenanthro­[9,10- d ]-imidazole (PPI), 9,10-diphenylimidazole, and pyrene-imidazole. It is necessary to develop more excellent acceptors for expanding HLCT material systems and realize high-efficiency OLEDs. ,− As shown in Figure a, benzoxazole has good planarity, high lowest unoccupied molecular orbital (LUMO) energy, and weak electron-withdrawing ability, which are good for deep-blue light emission but has been rarely reported .…”