A5101495213- TiO2 Photocatalysis and Solar Cells
- Advanced Photocatalysis Techniques
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Copper-based nanomaterials and applications
- Catalytic Processes in Materials Science
- Supercapacitor Materials and Fabrication
- Perovskite Materials and Applications
- Catalysis and Oxidation Reactions
- Electrocatalysts for Energy Conversion
- Advanced Nanomaterials in Catalysis
- Advancements in Battery Materials
- Transition Metal Oxide Nanomaterials
- Electrochemical sensors and biosensors
- Advanced battery technologies research
- Gold and Silver Nanoparticles Synthesis and Applications
- Nanocluster Synthesis and Applications
- Semiconductor materials and interfaces
- Solar-Powered Water Purification Methods
- Carbon and Quantum Dots Applications
- Electronic and Structural Properties of Oxides
- Conducting polymers and applications
- Polyoxometalates: Synthesis and Applications
- Hydrogen Storage and Materials
Los Alamos National Laboratory
2017-2020
University of Pennsylvania
2014-2016
Yeungnam University
2014
Seoul National University
2008-2013
Yonsei University
2009
Colloidal semiconductor quantum dots (QDs) are a highly promising materials platform for implementing solution-processable light-emitting diodes (LEDs). They combine high photostability of traditional inorganic semiconductors with chemical flexibility molecular systems, which makes them well-suited large-area applications such as television screens, solid-state lighting, and outdoor signage. Additional beneficial features include size-controlled emission wavelengths, narrow bandwidths,...
The light reaction in natural photosynthesis is generally recognized as one of the most efficient mechanisms for converting solar energy into other sources. We report herein on a novel strategy generating H(2) fuel via an artificial Z-scheme mechanism by mimicking that occurs green plants. Designing desirable photocatalyst leads to conduction band sufficiently high reduce protons, thus decreasing probability charge recombination. combined two visible sensitive photocatalysts, CdS and...
A variety of shape-controlled TiO2 nanoparticles, such as spheres, short ellipsoidal rods with a low aspect ratio (low AR), and long high (high were synthesized by gel−sol method. X-ray diffractometer ultraviolet diffuse reflectance spectroscopy analyses revealed that the nanoparticles have same anatase structure band-gap energy (Eg) 3.2 eV regardless nanoparticle shape. Electrochemical impedance (EIS) results showed increasing was accompanied increases in charge-transfer rate between...
Luminescent CuInS2 (CIS) quantum dots (QDs) exhibit highly efficient intragap emission and long, hundreds-of-nanoseconds radiative lifetimes. These spectral properties, distinct from structurally similar II–VI QDs, can be explained by the involvement of defect states containing a localized hole capable coupling with conduction band electron for transition. However, absolute energies band-edge states, structure emissive defect(s), role origin nonemissive decay channels still remain poorly...
The use of semiconductor nanocrystal quantum dots (QDs) in optoelectronic devices typically requires postsynthetic chemical surface treatments to enhance electronic coupling between QDs and allow for efficient charge transport QD films. Despite their importance solar cells infrared (IR) light-emitting diodes photodetectors, advances these lead chalcogenide (PbE; E = S, Se, Te) have lagged behind those of, instance, II–VI QDs. Here, we introduce a method fast effective ligand exchange PbE...
Colloidal quantum dots (QDs) of I-III-VI ternary compounds such as copper indium sulfide (CIS) and selenide (CISe) have been under intense investigation due to both their unusual photophysical properties considerable technological utility. These materials feature a toxic-element-free composition, tunable bandgap that covers near-infrared visible spectral energies, highly efficient photoluminescence (PL) whose spectrum is located in the reabsorption-free intragap region. make them attractive...
Enhancement of the charge transfer rate in CdSe quantum dot (QD) sensitized solar cells is one most important criteria determining cell efficiency. We report a novel strategy for enhancing by exchanging native, long organic chain to an atomic ligand, S(2-), with simple solid exchange process. S(2-)-ligand easily executed dipping QDs photoanode into formamide solution K2S. The results show that this process leads enhancement electronic coupling between QD and TiO2 removing insulating barrier...
A simple method is described for the preparation of Fe-doped TiO2 nanoparticles (Ti1−xFexO2) that can be used as a high performance support material CO oxidation catalyst. The allows one to fabricate Ti1−xFexO2 with uniform sizes and shapes. Microstructural studies using XRD, Raman spectroscopy EPR analyses indicate Fe dopant substitutionally incorporated by replacing Ti4+ cations. Electrochemical results that, when small amount molecules (less than 8 atomic%) are into structure, has greatly...
Light absorption and electron injection are important criteria determining solar energy conversion efficiency. In this research, monodisperse CdSe quantum dots (QDs) synthesized with five different diameters, the size-dependent efficiency of dot sensitized cell (QDSSCs) is investigated by employing atomic inorganic ligand, S(2-). Absorbance measurements transmission microscopy show that diameters uniform QDs 2.5, 3.2, 4.2, 6.4, 7.8 nm. Larger generate a larger amount charge under irradiation...
We present a general synthesis for family of n-type transparent conducting oxide nanocrystals through doping with aliovalent cations. These monodisperse exhibit localized surface plasmon resonances tunable in the mid- and near-infrared increasing dopant concentration. employ battery electrical measurements to demonstrate that plasmonic resonance isolated particles is consistent electronic properties nanocrystal thin films. Hall Seebeck show form degenerately doped solids free electron...
The emerging technology of colloidal quantum dot electronics provides an opportunity for combining the advantages well-understood inorganic semiconductors with chemical processability molecular systems. So far, most research on electronic devices has focused materials based Pb- and Cd chalcogenides. In addition to environmental concerns associated presence toxic metals, these dots are not well suited applications in CMOS circuits due difficulties integrating complementary n- p-channel...
Pt/TiO2 nanospheres and nanorods were used to generate hydrogen via water splitting the effect of shapes TiO2 nanoparticles evaluated for evolution. exhibited an increase in charge transfer rate between nanoparticle surface electrolyte. This led improvement photo-catalytic evolution during decomposition water.
Colloidal quantum dots (QDs) have attracted considerable attention as promising materials for solution-processable electronic and optoelectronic devices. Copper indium selenium sulfide (CuInSexS2–x or CISeS) QDs are particularly attractive an environmentally benign alternative to the much more extensively studied containing toxic metals such Cd Pb. Carrier transport properties of CISeS-QD films, however, still poorly understood. Here, we aim elucidate factors that control charge conductance...
The efficiency of TiO2-based dye-sensitized solar cells (DSSCs) has been limited because charge transfer is not fully achieved, and the injected electrons always recombine with acceptor species before electrode can collect them. novel device architecture offering graded bands into TiO2 photoanode network DSSCs presented to enhance power conversion (PCE). Mono (x %) as well (w–x–y–z W-doped films are prepared form intermediate in bandgap TiO2. A significant enhancement PCE achieved when mono...
Carbazole dimer enhances the charge injection and reduces recombination to exhibit superior p-type performance of DSSCs.