Highly stable and efficient copper(I) sensitizer for narrowband red organic light-emitting diodes with an operational lifetime (LT<sub>95</sub>) of up to 3689 h at 1000 cd m<sup>-2</sup>.

Tang, Rui; Xu, Shuo; Cheng, Gang; Low, Kam-Hung; Zhang, Dongdong; Duan, Lian; Che, Chi-Ming · Nat Commun · 2025

basic_science · Level V

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Abstract

Copper-based organic light-emitting diodes (OLEDs) are low-cost alternatives to precious metal-based OLEDs, but currently no such OLEDs can meet the practical requirements for high colour purity, device efficiency, and operational stability. Carbene-Cu(I)-amide emitters reported here exhibited thermally activated delayed fluorescent emission with quantum efficiencies up to 0.90 and radiative decay rates of 2.7 × 10<sup>6</sup> s<sup>-1</sup>. These enable blue to near-infrared Cu(I)-OLEDs with high brightness (265,000 cd m<sup>-2</sup>) and extended LT<sub>95</sub> lifetime (3582 hours at 1000 cd m<sup>-2</sup>). Deuteriation and π-extension of carbazole significantly enhance OLED stability. Cu(I)-sensitized fluorescence OLEDs showed efficient narrowband electroluminescence (λ<sub>max</sub> 612-614 nm; full-width half maximum of 33-38 nm; maximum external quantum efficiencies reach 21.9%) and prolonged LT<sub>95</sub> lifetime (up to 3689 h at 1000 cd m<sup>-2</sup>). This work highlights earth-abundant metal-based sensitized-OLEDs that exhibit high colour purity and long device lifetime comparable to the best non-iridium metal-based OLEDs.