title: Fabrication of high quantum yield quantum dot/polymer films by enhancing dispersion of quantum dots using silica particles.
abstract: We have fabricated quantum dot (QD)/polymer films of high quantum yield by coating silica particles with quantum dots. When particles were dispersed in tetrahydrofuran, free QD suspension exhibited higher quantum yield than QD-coated silica particles. Scattering is a most likely reason for the drop in quantum yield for the QD-coated silica particles, as supported by results of silica particles with varying morphologies: for example, QD-coated hollow silica particles showed higher quantum yield than filled silica particles, as the hollowness gave rise to reduced scattering. In the QD/polymer films, however, QD-coated filled/hollow silica particles showed significant enhancement in quantum yield (i.e., up to 2.4 times higher than that of free QDs). Confocal microscopy revealed that the enhanced quantum yield likely results from improved dispersion of QD-coated silica particles. In addition, the quantum yield of QD-coated hollow silica particles in films was lower than that of filled particles because of lower structural stability. Introducing silica (either filled or hollow) particles prevents spectral redshift of emission peak when prepared in the form of film, as opposed to QD-only sample. Our findings point to the possibility that QD-coated filled/hollow silica particles exhibit superior stability, quantum efficiency, and color accuracy, which render them potentially useful for the next-generation light-emitting devices and photovoltaics.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, Republic of Korea.
authors.forename: Hyun Chang
authors.initials: HC
authors.lastname: Kim
authors.forename: Hyun-Guk
authors.initials: HG
authors.lastname: Hong
authors.forename: Cheolsang
authors.initials: C
authors.lastname: Yoon
authors.forename: Hoon
authors.initials: H
authors.lastname: Choi
authors.forename: Ik-Sung
authors.initials: IS
authors.lastname: Ahn
authors.forename: Doh C
authors.initials: DC
authors.lastname: Lee
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Kangtaek
authors.initials: K
authors.lastname: Lee
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D010316:Particle Size; D045663:Quantum Dots; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon; D012822:Silicon Dioxide