Sensitized Fluorescence Organic Light-Emitting Diodes with Reduced Efficiency Roll-Off

Abstract

Thermally activated delayed fluorescence (TADF)-sensitized fluorescence is a promising strategy to maintain the advantage of TADF materials and fluorescent materials. Nevertheless, the delayed lifetime of the TADF sensitizer is still relatively long, which causes heavy efficiency roll-off. Here we reported a valid tactic to construct fluorescent devices with low-efficiency roll-off by utilizing the TADF sensitizer with a reduced delayed lifetime. By the construction of the sensitization system, the energy transfer efficiency can reach up to 90%. The high-energy transfer efficiency and the TADFʼs short delayed lifetime result in high sensitization over 95% and the maximum external quantum efficiency of 16.2%. Meanwhile, the TADF-sensitized fluorescent devices exhibit reduced efficiency roll-off with an “onset” current density of 23 mA · cm⁻². Our results provide an effective strategy to reduce the efficiency roll-off of the TADF sensitization system.

Key words

OLED - fluorescence - TADF

Publication History

Received: 11 October 2021

Accepted: 17 November 2021

Accepted Manuscript online:
02 December 2021

Article published online:
27 December 2021

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