Kwang-Sup Lee

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Water soluble porphyrins were designed and prepared by Williamson ether synthesis reaction between tetrakis(p-bromomethylphenyl)porphyrin and polyethylene glycol (PEG) for photodynamic therapy. The quantum yields for the generation of singlet oxygen of tetra-polyethylene glycol branched porphyrin shows above 80% in D2O. Luminescence of singlet state oxygen(More)
The precise mechanism and dynamics of charge generation and recombination in bulk heterojunction polymer:fullerene blend films typically used in organic photovoltaic devices have been intensively studied by many research groups, but nonetheless remain debated. In particular the role of interfacial charge-transfer (CT) states in the generation of free charge(More)
We report polymeric nanomicelles doped with organic fluorophores (StCN, (Z)-2,3-bis[4-(N-4-(diphenylamino)styryl)phenyl]-acrylonitrile), which have the property of aggregation-enhanced fluorescence. The fluorescent nanomicelles have two unique features: (1) They give much brighter fluorescence emission than mono-fluorophores. (2) The nanomicelles with(More)
We have functionalized core-shell CdSe/ZnS quantum dots (QDs) with a photosensitive monolayer, rendering them solution processable and photopatternable. Upon exposure to ultraviolet radiation, films composed of this material were found to polymerize, forming interconnected arrays of QDs. The photoluminescence properties of the nanocrystal films increased(More)
In this study, we report a neo-conceptive three-dimensionally (3D) crossing manifold micromixer (CMM) embedded in microchannel. Fabricated by sequential processes of photolithography and two photon absorption stereolithography, this leads to a microfluidic system with a built-in micromixer in a site controlled manner. The effectiveness of CMM is(More)
We report an approach to produce predefined patterns of quantum dots and multipod nanocrystals using optical lithography for direct writing of films for optoelectronic and electronic devices. To obtain photopatternability, the nanostructures (for example, CdSe, CdTe, and PbSe nanocrystals) were functionalized by incorporation of the functional ligand(More)
This study reports the synthesis and the investigation of optical behaviors of a stilbene derivative, (Z)-2,3-bis[4-(N-4-(diphenylamino)styryl)phenyl]acrylonitrile (StCN). The nanoaggregates of StCN in 50% water/DMF have exhibit an increased fluorescence intensity and a blue shift with emission maximum wavelength with respect to StCN in 100% N,(More)
A novel method for the fabrication of polypyrrole nanotubes (PPyNTs) possessing quantum dots (QDs) was developed for optoelectronic devices. PbSe QDs were effectively attached to the thiolated PPyNT-SH without affecting the dispersion stability of QDs and hence ensuring their homogeneous distribution in the polymer. Transmission electron microscopic images(More)
In this paper, the surface modification of CdSe- and CdZnS-based quantum dots (QDs) with a functional silica shell is reported. Functionalized silica shells are prepared by two routes: either by ligand exchange and a modified Stöber process or by a miniemulsion process with amphiphilic poly(oxyethylene) nonylphenylether also know as Igepal CO-520 (IG) as(More)
Quantum dots (QDs) are semiconductor nanocrystals with peculiar optoelectronic properties. Their wide application in light-emitting diodes, solar cells, and the medical and defense fields makes them a potential candidate in the area of photonics and biophotonics. In this feature issue of Optical Materials Express, together with Optics Express we focus on(More)