An efficient and weak efficiency-roll-off near-infrared (NIR) polymer light-emitting diode (PLED) based on a PVK-supported Zn2+–Yb3+-containing metallopolymer

Abstract

Based on copolymerization of NVK (N-vinylcarbazole) with an efficient Yb³⁺-centered NIR luminescent complex monomer [Zn(L¹)(4-vinyl-Py)Yb(L²)₃] (3) (H₂L¹ = N,N′-bis(salicylidene)cyclohexane-1,2-diamine, 4-vinyl-Py = 4-vinyl-pyridine, and HL² = (Z)-3-methyl-1-phenyl-4-(2,2,2-trifluoro-1-hydroxyethylidene)-1H-pyrazol-5(4H)-one), the obtained single Zn²⁺–Yb³⁺-containing metallopolymer Poly(NVK-co-3) with an additional PVK (poly(N-vinylcarbazole))-to-Yb³⁺ Föster energy transfer was used as the emitting layer for the realization of NIR PLEDs. Moreover, among the Yb³⁺-centered NIR PLEDs, the superior performance (irradiances of 80.14–85.63 μW cm⁻² and efficiencies of 0.05–0.058%) of the 75 : 1 feeding devices, the advantages of a low turn-on voltage (5–8 V), and the weak efficiency-roll-off relative to that of the small-molecule organo-Yb³⁺-based NIR OLEDs render the Yb³⁺-containing metallopolymer a new platform for PLEDs with wavelength above 900 nm.