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Enhanced Photoluminescence in Quantum Dots–Porous Polymer Hybrid Films Fabricated by Microcellular Foaming
Author(s) -
Yu Shudong,
Fritz Benjamin,
Johnsen Siegbert,
Busko Dmitry,
Richards Bryce S.,
Hippler Marc,
Wiegand Gabriele,
Tang Yong,
Li Zongtao,
Lemmer Uli,
Hölscher Hendrik,
Gomard Guillaume
Publication year - 2019
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201900223
Subject(s) - materials science , photoluminescence , absorption (acoustics) , quantum dot , polymer , optoelectronics , porosity , porous medium , light scattering , chemical engineering , nanotechnology , composite material , scattering , optics , engineering , physics
The color conversion efficiency of thin polymeric layers embedding quantum dots (QDs) is limited by their negligible light scattering ability and by the insufficient absorption of the excitation photons. In this study, a route is presented to tackle these optical shortcomings by introducing a tailored network of micropores inside these hybrid films. This is achieved by exploiting the microcellular foaming approach which is rapid, cost effective and only makes use of a green solvent (supercritical carbon dioxide). With an appropriate combination of the applied pressure and temperature during foaming, and by using a proper film thickness, the photoluminescence (PL) intensity is enhanced by a factor of up to 6.6 compared to an equivalent but unfoamed hybrid film made of CdSe/ZnS QDs in a polymethyl methacrylate matrix. Spectroscopic measurements and ray tracing simulations reveal how the porous network assists UV/blue light absorption by the QDs and the subsequent outcoupling of the converted light. The approach improves the PL for various QD concentrations and can be easily scaled up and extended to other polymeric matrices as well as light converting materials.