A5088860714- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Quantum Dots Synthesis And Properties
- Copper-based nanomaterials and applications
- ZnO doping and properties
- Conducting polymers and applications
- Advanced Photocatalysis Techniques
- Semiconductor materials and interfaces
- Solid-state spectroscopy and crystallography
- Advanced Semiconductor Detectors and Materials
- Ga2O3 and related materials
- Electronic and Structural Properties of Oxides
- X-ray Diffraction in Crystallography
- Gas Sensing Nanomaterials and Sensors
- Silicon and Solar Cell Technologies
- Thin-Film Transistor Technologies
- solar cell performance optimization
- Quasicrystal Structures and Properties
- Semiconductor materials and devices
- Crystallization and Solubility Studies
- Silicon Nanostructures and Photoluminescence
- Mineralogy and Gemology Studies
- Transition Metal Oxide Nanomaterials
- Organic Electronics and Photovoltaics
- Organic Light-Emitting Diodes Research
University of Toledo
2016-2025
Beihang University
2024
National Renewable Energy Laboratory
2006-2023
Oak Ridge National Laboratory
1997-2023
University of Toronto
2023
Sandia National Laboratories
2022
University of Washington
2022
University of Manitoba
1997-2022
United States Department of State
2020
Iowa State University
2020
Thin-film solar cells based on Methylammonium triiodideplumbate (CH3NH3PbI3) halide perovskites have recently shown remarkable performance. First-principle calculations show that CH3NH3PbI3 has unusual defect physics: (i) Different from common p-type thin-film cell absorbers, it exhibits flexible conductivity good p-type, intrinsic to n-type depending the growth conditions; (ii) Dominant defects create only shallow levels, which partially explain long electron-hole diffusion length and high...
Halide perovskites solar cells have the potential to exhibit higher energy conversion efficiencies with ultrathin films than conventional thin-film based on CdTe, CuInSe2, and Cu2ZnSnSe4. The superior solar-cell performance of halide may originate from its high optical absorption, comparable electron hole effective mass, electrically clean defect properties, including point defects grain boundaries.
Lead halide perovskite solar cells with the high efficiencies typically use high-temperature processed TiO2 as electron transporting layers (ETLs). Here, we demonstrate that low-temperature solution-processed nanocrystalline SnO2 can be an excellent alternative ETL material for efficient cells. Our best-performing planar cell using such a has achieved average efficiency of 16.02%, obtained from measured both reverse and forward voltage scans. The outstanding performance ETLs is attributed to...
Molecular piezoelectrics are highly desirable for their easy and environment-friendly processing, light weight, low processing temperature, mechanical flexibility. However, although 136 years have passed since the discovery in 1880 of piezoelectric effect, molecular with a coefficient d33 comparable piezoceramics such as barium titanate (BTO; ~190 picocoulombs per newton) not been found. We show that trimethylchloromethyl ammonium trichloromanganese(II), an organic-inorganic perovskite...
Efficient all-perovskite tandem cells Organic-inorganic perovskite films can boost the output of conventional silicon solar in geometries by utilizing more light at blue end spectrum. Tandem that use only have been less successful because lack a suitable material with low bandgap replace silicon. Tong et al. report mixed tin-lead organic-inorganic containing small fraction guanidinium thiocyanate has bandgap, long charge-carrier lifetime, and efficiencies around 25%. Science , this issue p. 475
Computational, thin-film deposition, and characterization approaches have been used to examine the ternary halide semiconductor Cs3Sb2I9. Cs3Sb2I9 has two known structural modifications, 0-D dimer form (space group P63/mmc, no. 194) 2-D layered (P3̅m1, 164), which can be prepared via solution solid-state or gas-phase reactions, respectively. Our computational investigations suggest that form, is a one-third Sb-deficient derivative of ubiquitous perovskite structure, potential candidate for...
Efficient lead (Pb)-free inverted planar formamidinium tin triiodide (FASnI3 ) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversion efficiencies (PCEs) of 5.41% ± 0.46% and a maximum PCE 6.22% under forward voltage scan. The exhibit small photocurrent-voltage hysteresis high reproducibility. champion cell shows steady-state efficiency ≈6.00% for over 100 s.
We report the first-principles electronic structure of BiVO4, a promising photocatalyst for hydrogen generation. BiVO4 is found to be direct band gap semiconductor, despite having extrema away from Brillouin zone center. Coupling between Bi 6s and O 2p forces an upward dispersion valence at boundary; however, maintained via coupling V 3d, 2p, 6p, which lowers conduction minimum. These interactions result in symmetric hole electron masses. Implications design ambipolar metal oxides are discussed.
The concept of electronic dimensionality,<italic>i.e.</italic>, the connectivity atomic orbitals that comprise lower conduction band and upper valence band, is introduced to better account for device performance perovskite-based solar cells.
Searching for novel functional materials represents an important direction in the research and development of renewable energy. Due to their unique structural compositional flexibility high material stability, oxide perovskites derivatives have recently been extensively explored as a class versatile applications electrocatalysis (EC), photocatalysis (PC) photovoltaics (PV), showing great promise terms catalytic activity device stability. In this review, we firstly discuss extreme...
Utilizing Fe3O4 nanorods as the active Li+ storage material and 5 wt% carbon single-walled nanotubes (SWNTs) a "conductive net," Li-ion anode with high reversible capacity of 1000 mAh g−1 (∼2000 cm−3) at C rate is demonstrated. The electrodes exhibit high-rate capability stable capacities 800 5C ∼600 10C.
Using density-functional theory calculations, we analyze the optical absorption properties of lead (Pb)-free metal halide perovskites (AB$^{2+}$X$_3$) and double (AB$^+$B$^{3+}$X$_6$) (A = Cs or monovalent organic ion, B$^{2+}$ non-Pb divalent metal, B$^+$ B$^{3+}$ trivalent X halogen). We show that, if is not Sn Ge, Pb-free exhibit poor absorptions because their indirect bandgap nature. Among nine possible types perovskites, six have direct bandgaps. Of these types, four inversion...
Lead thiocyanate in the perovskite precursor can increase grain size of a thin film and reduce conductivity boundaries, leading to solar cells with reduced hysteresis enhanced fill factor. A planar cell boundary interface passivation achieves steady-state efficiency 18.42%.
Abstract The double perovskite family, A 2 M I III X 6 , is a promising route to overcome the lead toxicity issue confronting current photovoltaic (PV) standout, CH 3 NH PbI . Given generally large indirect band gap within most known perovskites, band‐gap engineering provides an important approach for targeting outstanding PV performance this family. Using Cs AgBiBr as host, through alloying of In /Sb has been demonstrated in work. Ag(Bi 1− x )Br (M=In, Sb) accommodates up 75 % with...
Abstract Quantum efficiencies of organic-inorganic hybrid lead halide perovskite light-emitting devices (LEDs) have increased significantly, but poor device operational stability still impedes their further development and application. All-inorganic perovskites show better than the counterparts, performance respective films used in LEDs is limited by large grain sizes, which lowers radiative recombination probability results boundary related trap states. We realize smooth pinhole-free,...
We report on the synthesis and electrochemical properties of oriented NiO-TiO(2) nanotube (NT) arrays as electrodes for supercapacitors. The morphology films prepared by electrochemically anodizing Ni-Ti alloy foils was characterized scanning transmission electron microscopies, X-ray diffraction, photoelectron spectroscopies. morphology, crystal structure, composition NT were found to depend preparation conditions (anodization voltage postgrowth annealing temperature). Annealing as-grown a...
Efficient lead halide perovskite solar cells use hole-blocking layers to help collection of photogenerated electrons and achieve high open-circuit voltages. Here, we report the realization efficient grown directly on fluorine-doped tin oxide-coated substrates without using any layers. With ultraviolet–ozone treatment substrates, a planar Au/hole-transporting material/CH3NH3PbI3-xClx/substrate cell processed by solution method has achieved power conversion efficiency over 14% an voltage 1.06...