An efficient solution-processable non-doped hybridized local and charge-transfer (HLCT) emitter for a simplified organic light-emitting diode. (21st September 2022)

• Record Type: Journal Article
• Authors: Loythaworn, Thidarat; Petdee, Sujinda; Chasing, Pongsakorn; Chantanop, Nuttapong; Therdkatanyuphong, Pattarawadee; Waengdongbung, Wijitra; Sudyoadsuk, Taweesak; Promarak, Vinich
• Is Part Of: Materials chemistry frontiers. Volume 6:Number 21(2022)
• Page Start: 3225
• Page End: 3236
• Publication Date: 2022-09-21
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/d2qm00401a
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : A solution-processable HLCT fluorescent molecule realizes a highly efficient non-doped OLED with a high brightness of 30 800 cd m −2, a maximum external quantum efficiency (EQEmax ) of 6.74% and a maximum current efficiency (CEmax ) of 14.38 cd A −1 . Abstract : Here, a new solution-processable hybridized local and charge-transfer (HLCT) fluorescent molecule, CPBzFC, is designed and synthesized as an efficient emitter for low-cost and simple-structured electroluminescent devices. CPBzFC contains 7-(4-(carbazol- N -yl)phenyl)benzothiadiazole as an HLCT fragment directly linked to a hole-transporting and highly soluble 7-(3, 6-di- tert -butylcarbazol- N -yl)-9, 9′-bis(8-(3, 6-di- tert -butylcarbazol- N -yl)octyl)fluorene part. The photophysical results and theoretical calculations unveil an HLCT excited-state character with a strong yellowish-green fluorescence emission (a solid-state photoluminescence quantum yield of 82%), decent hole-transporting mobility, good film morphology, and thermal and electrochemical stabilities. CPBzFC is successfully utilized as a solution-processed non-doped emitter in simple structured OLEDs. This device achieves excellent electroluminescence (EL) performance with an ultra-high brightness of 30 800 cd m −2, a maximum external quantum efficiency (EQEmax )of 6.74%, a maximum current efficiency (CEmax ) of 14.38 cd A −1, and a high exciton utilization efficiency (EUE) of 41%.