Near-Infrared (NIR) polymer light-emitting diode (PLED) based on organo-Yb3+-complex-grafted poly(N-vinylcarbazole) (PVK)

Through free-radical copolymerization of the Yb3+-centered near-infrared (NIR) luminescent complex monomer [Zn(L-1)(4-vinyl-Py)Yb(L-2)(3)] (2) (H2L1 = N, N'-bis(salicylidene) -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) with NVK (N-vinylcarbazole), the obtained [Zn(L-1)(4-vinyl-Py) Yb(L-2)(3)]-grafted polymer Poly(NVK-co-2) with additional PVK (Poly(N-vinylcarbazole)) to Yb3+ ion Foster energy transfer is used as the emitting material of polymer light-emitting diode (PLED), exhibiting the Yb3+-centered NIR outputs at 980 nm with a maximum efficiency of 0.049% (at 5.62 mA/cm(2)) and a maximum irradiance of 78.68 mu W/cm(2) (at 16 V), respectively. This superior performance to those of previously reported organo-Yb3+-doped polymer systems, together with the characters of low turn-on voltage of 7 V and weak efficiency-roll-off (0.049-0.031% upon 5.62-233.6 mA/cm(2)), indicates that organo-Yb3+-grafted polymer is an effective strategy to develop PLEDs with the wavelength extended to 980 nm.