Synthesis and characterization of one star-shaped polymer with charged iridium complex as luminescent core

One new three-arm star-shaped polymer was synthesized by the core-first way using atom transfer radical polymerization (ATRP) method. This polymer contained charged iridium (Ir) complex as the luminescent core and 2-(carbazol-9-yl) ethyl methacrylate as the arm repeat unit. Its structure was confirmed by elemental analysis, nuclear magnet resonance (NMR) and photoluminescence (PL). The polymer has a relatively low polydispersity index (PDI) of 1.30 with excellent thermal stability. It also possesses significant redox behavior with a HOMO level of -5.21 eV, which will be of benefit to hole-injection. The PL spectrum of the polymer in film state has a stable peak at 565 nm, however, its PL in dichloromethane solution varied with its concentration. It demonstrated effective energy transfer from the arm unit to the core in the hostguest system. This indicated that when the length of the arm is properly designed, highly luminescent materials can be achieved with emission at 565 nm.