A5007621639- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Silicon Nanostructures and Photoluminescence
- solar cell performance optimization
- Semiconductor materials and interfaces
- Photovoltaic System Optimization Techniques
- Nanowire Synthesis and Applications
- Force Microscopy Techniques and Applications
- Chalcogenide Semiconductor Thin Films
- Photodynamic Therapy Research Studies
- Optical Coatings and Gratings
- Mechanical and Optical Resonators
- Advanced Radiotherapy Techniques
- Nanoplatforms for cancer theranostics
- Medical Imaging and Pathology Studies
- Semiconductor materials and devices
- Elbow and Forearm Trauma Treatment
- NMR spectroscopy and applications
- Semiconductor Quantum Structures and Devices
- Electrohydrodynamics and Fluid Dynamics
- Photonic Crystals and Applications
- Cardiac pacing and defibrillation studies
- Transition Metal Oxide Nanomaterials
- Phase-change materials and chalcogenides
- Advanced Breast Cancer Therapies
University of Maryland, College Park
2021-2025
National Institutes of Health Clinical Center
2023-2024
National Cancer Institute
2023-2024
Incyte (United States)
2024
Nanchong Central Hospital
2023
China University of Petroleum, Beijing
2023
National Institutes of Health
2022
Lucile Packard Children's Hospital
2022
American Solar (United States)
2000-2013
National Renewable Energy Laboratory
1998-2011
We have achieved 14.6% initial and 13.0% stable conversion efficiencies using an amorphous silicon-based alloy in a spectrum-splitting, triple-junction structure. These been confirmed independently by the National Renewable Energy Laboratory. Key factors leading to this major advance include improvements made low band-gap silicon–germanium cell, pn tunnel junction between component cells, top conducting oxide.
We present our development of n-type nano-structured hydrogenated silicon oxide (nc-SiOx:H) as a dual-function layer in multi-junction solar cells. optimized nc-SiOx:H and attained conductivity suitable for doped optical property an inter-reflection layer. tested the effectiveness by replacing normal n between middle bottom cells a-Si:H/a-SiGe:H/nc-Si:H triple-junction structure. A significant gain cell current density ∼1.0 mA/cm2 is achieved. further component structures initial active-area...
We investigate why high levels of hydrogen dilution the process gas lead to enhanced light soaking stability amorphous silicon (a-Si) alloy solar cells by studying microstructural properties material using high-resolution transmission electron microscopy (TEM) and Raman spectroscopy. The TEM results show that a-Si (with or without dilution) is a heterogeneous mixture network linear-like objects evidence order along their length. volume fraction these ordered regions increases with increasing...
We have developed a microcrystalline fluorinated p+ silicon alloy which has high dark conductivity and low optical loss. Incorporation of this material in single tandem amorphous based solar cells resulted increased open circuit voltage conversion efficiency.
We have developed an amorphous silicon alloy based solar cell with a novel structure in which the optical gap of intrinsic layer changes substantial portion bulk. Computer simulation studies show that for given short circuit current, it is possible this to obtain higher open voltage and fill factor than conventional design. Experimental structures been made confirm theoretical prediction. The new design shows considerable improvement efficiency. Incorporation bottom triple device has...
High-hydrogen-diluted films of hydrogenated amorphous Si (a-Si:H) 0.5 μm in thickness and optimized for solar cell efficiency stability, are found to be partially microcrystalline (μc) if deposited directly on stainless steel (SS) substrates but fully a thin n layer a-Si:H or μc-Si:H is first the SS. In these latter cases, partial microcrystallinity develops as grown thicker (1.5–2.5 μm) this accompanied by sharp drops open circuit voltage. For films, x-ray diffraction (XRD) shows improved...
We have studied the effect of texture in Ag/ZnO back reflectors (BRs) on performance hydrogenated nanocrystalline silicon (nc-Si:H) solar cells. While a larger provides superior light trapping, it also deteriorates nc-Si:H quality. used total and diffused reflection atomic force microscopy to evaluate BR texture. A with textured Ag thin ZnO layers has been found give best cell performance. Using optimized BR, we achieved an initial active-area efficiency 10.2% single-junction stable...
The structural properties of hydrogenated microcrystalline silicon solar cells are investigated using Raman, x-ray diffraction, and atomic force microscopy. experimental results showed a significant increase volume fraction grain size with increasing film thickness. correlation between the cell performance microstructure suggests that thickness is main reason for deterioration as intrinsic layer increases. By varying hydrogen dilution in gas mixture during deposition, evolution has been...
Using a combination of infrared absorption and small-angle x-ray scattering on hydrogenated amorphous silicon alloy films efficiency measurements solar cells with intrinsic layers prepared under nominally identical conditions to those for the deposition films, we observe correlation between microstructure in cell performance. With increasing microvoid density, both initial light-degraded performance are found deteriorate.
CDK2 is a critical regulator of the cell cycle. For variety human cancers, dysregulation CDK2/cyclin E1 can lead to tumor growth and proliferation. Historically, early efforts develop inhibitors with clinical applications proved unsuccessful due challenges in achieving selectivity over off-target CDK isoforms associated toxicity. In this report, we describe discovery (4-pyrazolyl)-2-aminopyrimidines as potent class that display CDKs 1, 4, 6, 7, 9. SAR studies led identification compound 17,...
Using infrared absorption (ir) spectroscopy, H evolution, and x-ray diffraction (XRD), the structure of high-H-dilution, plasma-enhanced chemical vapor deposition $a\ensuremath{-}\mathrm{S}\mathrm{i}:\mathrm{H}$ films ``on edge crystallinity'' is examined. From ir Si-H wag mode peak frequency XRD results, we postulate existence very small Si crystallites contained within as-grown amorphous matrix with majority bonded located on these crystallite surfaces. Upon annealing, a low-temperature...
Light-induced metastability in hydrogenated nanocrystalline silicon (nc-Si:H) single-junction solar cells has been studied under different light spectra. The nc-Si:H contains a certain fraction of amorphous (a-Si:H). We observe no light-induced degradation when the photon energy used is lower than bandgap a-Si:H, while occurs higher bandgap. conclude that defect generation mainly phase. Light soaking experiments on a-Si:H∕a-SiGe:H∕nc-Si:H triple-junction show bottom cell, because a-Si:H top...
Abstract This paper reviews our progress of using nc‐Si:H as a low bandgap absorber material to substitute for a‐SiGe:H alloys in multi‐junction solar cells. We have focused on three topics: (1) high deposition rate, (2) large area uniformity thickness and properties, (3) cell module efficiencies. Initially, we investigated various methods, including RF, VHF, microwave glow discharges. After several years systematic studies, been convinced that VHF discharge is an applicable method attain...
Metal-insulator-semiconductor-type photovoltaic devices using amorphous Si:F:H alloys have been fabricated. Conversion efficiencies of up to 6.3% under AM:1 illumination observed. These represent the highest yet reported for thin-film solar cells.
We have investigated the effects of both forward bias current soaking in dark and prolonged light exposure on photovoltaic properties lightly doped, n- p-type hydrogenated amorphous silicon Schottky barrier diodes. The results show that recombination rather than single carrier trapping is responsible for light-induced changes.
The performance of dual-band gap, double-junction amorphous silicon alloy-based solar cells in which the component have different degrees current mismatch has been studied under annealed and light-soaked conditions. Using a profiled band gap silicon-germanium alloy bottom cell, stabilized active-area efficiency 11.16% achieved.