We report on the fabrication of mesoporous TiO2 nanowire film for PbS/TiO2 heterojuction solar ce... more We report on the fabrication of mesoporous TiO2 nanowire film for PbS/TiO2 heterojuction solar cells. We achieved improved short circuit current and a remarkable power converting efficiency of 5.5% under 8.5 mW/cm2 white light illumination.
ABSTRACT We report high performance enhancement in an all-solution processed polymer LED by incor... more ABSTRACT We report high performance enhancement in an all-solution processed polymer LED by incorporating large density of colloidal Ag nanoparticles. A 11-fold maximum luminance enhancement and a 20-fold maximum current efficiency enhancement are observed.
Frontiers in Optics 2011/Laser Science XXVII, 2011
Abstract We report a solution-based method producing hybrid heterostructures for light-emission i... more Abstract We report a solution-based method producing hybrid heterostructures for light-emission in the near-IR. This low-cost and versatile approach is most useful for flexible or reconfigurable optoelectronics, energy harvesting and biosensing platforms.
ABSTRACT This report demonstrates a surface plasmon-enhanced polymer-based LED (PLED) architectur... more ABSTRACT This report demonstrates a surface plasmon-enhanced polymer-based LED (PLED) architecture incorporating colloidal Ag nanoparticles in an all-solution fabrication process using orthogonal solvents. Oleylamine capping groups on the Ag nanoparticles provide an individual spacer layer for nanoparticles and prevent exciton dissociation and carrier trapping on Ag nanoparticles in this device structure. The large density of localized surface plasmon (SP) modes, strong exciton-SP mode coupling, and reduced cathode quenching achieved by Ag nanoparticles incorporation between the luminescent polymer and the metal cathode lead to a 20-fold luminance enhancement and a 50-fold current efficiency enhancement.
Benzenedithiol (BDT) and ethanedithiol (EDT) ligand-exchange treatments can be used to cross-link... more Benzenedithiol (BDT) and ethanedithiol (EDT) ligand-exchange treatments can be used to cross-link colloidal PbS quantum dots into nanocrystalline film structures with distinct optoelectronic properties. Such structures can provide a unique platform to study the energy transfer between layers of quantum dots with different sizes. In this report, efficient exciton funneling and recycling of surface state-bound excitons is observed in cascaded PbS quantum dot-based multilayered superstructures, where the excitons transfer from the larger band gap or donor layers to the smallest band gap or acceptor layers. In this system, both the BDT- and EDT-treated cascaded structures exhibit dramatically enhanced photoluminescence from the acceptor layers. As we show, the energy transfer mechanisms involved and their efficiencies are significantly different depending on the ligand-exchange treatment. In the future, we believe these efficient exciton recycling and funneling mechanisms could be used to improve significantly the photocurrent, charge-transport, and conversion efficiencies in low-cost nanocrystalline and hybrid solar cells and the emission efficiencies in hybrid light-emitting devices.
We report on the fabrication of mesoporous TiO2 nanowire film for PbS/TiO2 heterojuction solar ce... more We report on the fabrication of mesoporous TiO2 nanowire film for PbS/TiO2 heterojuction solar cells. We achieved improved short circuit current and a remarkable power converting efficiency of 5.5% under 8.5 mW/cm2 white light illumination.
ABSTRACT We report high performance enhancement in an all-solution processed polymer LED by incor... more ABSTRACT We report high performance enhancement in an all-solution processed polymer LED by incorporating large density of colloidal Ag nanoparticles. A 11-fold maximum luminance enhancement and a 20-fold maximum current efficiency enhancement are observed.
Frontiers in Optics 2011/Laser Science XXVII, 2011
Abstract We report a solution-based method producing hybrid heterostructures for light-emission i... more Abstract We report a solution-based method producing hybrid heterostructures for light-emission in the near-IR. This low-cost and versatile approach is most useful for flexible or reconfigurable optoelectronics, energy harvesting and biosensing platforms.
ABSTRACT This report demonstrates a surface plasmon-enhanced polymer-based LED (PLED) architectur... more ABSTRACT This report demonstrates a surface plasmon-enhanced polymer-based LED (PLED) architecture incorporating colloidal Ag nanoparticles in an all-solution fabrication process using orthogonal solvents. Oleylamine capping groups on the Ag nanoparticles provide an individual spacer layer for nanoparticles and prevent exciton dissociation and carrier trapping on Ag nanoparticles in this device structure. The large density of localized surface plasmon (SP) modes, strong exciton-SP mode coupling, and reduced cathode quenching achieved by Ag nanoparticles incorporation between the luminescent polymer and the metal cathode lead to a 20-fold luminance enhancement and a 50-fold current efficiency enhancement.
Benzenedithiol (BDT) and ethanedithiol (EDT) ligand-exchange treatments can be used to cross-link... more Benzenedithiol (BDT) and ethanedithiol (EDT) ligand-exchange treatments can be used to cross-link colloidal PbS quantum dots into nanocrystalline film structures with distinct optoelectronic properties. Such structures can provide a unique platform to study the energy transfer between layers of quantum dots with different sizes. In this report, efficient exciton funneling and recycling of surface state-bound excitons is observed in cascaded PbS quantum dot-based multilayered superstructures, where the excitons transfer from the larger band gap or donor layers to the smallest band gap or acceptor layers. In this system, both the BDT- and EDT-treated cascaded structures exhibit dramatically enhanced photoluminescence from the acceptor layers. As we show, the energy transfer mechanisms involved and their efficiencies are significantly different depending on the ligand-exchange treatment. In the future, we believe these efficient exciton recycling and funneling mechanisms could be used to improve significantly the photocurrent, charge-transport, and conversion efficiencies in low-cost nanocrystalline and hybrid solar cells and the emission efficiencies in hybrid light-emitting devices.
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