Quantum Dot-Block Copolymer Hybrids with Improved Properties and Their Application to Quantum Dot Light-Emitting Devices

To combine the optical properties of CdSe@ZnS quantum dots (QDs) with the electrical properties of semiconducting polymers, we prepared QD/polymer hybrids by grafting a block copolymer (BCP) containing thiol-anchoring moieties (poly(para-methyl triphenylamine-b-cysteamine acrylamide)) onto the surfaces of QDs through the ligand exchange procedure. The prepared QD/polymer hybrids possess improved processability such as enhanced solubility in various organic solvents as well as the film formation properties along with the improved colloidal stability derived from the grafted polymer shells. We also demonstrated light-emitting diodes based on QD/polymer hybrids, exhibiting the improved device performance (i.e., 3-fold increase in the external quantum efficiency) compared with the devices prepared by pristine (unmodified) QDs.This work was financially supported by the International Research Training Group: Self Organized Materials for Optoelectronics Mainz-Seoul jointly supported by the DFG (stipend for M.Z.) and the Korea Science and Engineering Foundation (KOSEF). This work was also supported in part by the KOSEF through the Acceleration Research Program (R17-2007-059-01000-0), the NANO Systems Institute-National Core Research Program (NSI-NCRC) (R15-2003-032-02002-0), World Class University (WCU) Program (400-2008-0230), and the National Research Laboratory (NRL) Program grant (R0A-2008-000-20108-0)