Monochromic Red-Emitting Nonconjugated Copolymers Containing Double-Carrier-Trapping Phosphine Oxide Eu3+ Segments: Toward Bright and Efficient Electroluminescence

Abstract

Two metallopolymers P1 and P2 were prepared by using a novel polymerizable Eu3+ complex Eu(TTA)3VBADPO (EuMA) (TTA = 2-thenoyltrifluoroacetonate) and vinylcarbazole as the monomers in the ratios of 1:99 and 3:97, respectively, in which VBADPO is 2-(diphenylphosphoryl)-N-(2-(diphenylphosphoryl)-4-methoxyphenyl)-4-methoxy-N-(4-vinylbenzyl)aniline as a polymerizable aryl phosphine oxide ligand with a bipolar structure. The copolymers exhibit the excellent optical properties with photoluminescence quantum yield more than 60% in film. Both Gaussian simulation and electrochemical analysis indicated that the Eu3+-complexed segments form double-carrier traps (Eu-trap) in the copolymers with depth of 0.1 eV for the hole and 0.7 eV for the electron. The single-layer spin-coated devices of P1 and P2 realized the pure red emissions from Eu3+ ions. The biggest luminance of 149.1 cd m–2 was achieved, which is the highest among those of electroluminescent (EL) Eu3+-containing copolymers reported so far. The unusual effi...