A5064811091- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Perovskite Materials and Applications
- Iron-based superconductors research
- Rare-earth and actinide compounds
- Inorganic Chemistry and Materials
- 2D Materials and Applications
- Quantum Dots Synthesis And Properties
- Crystal Structures and Properties
- Chalcogenide Semiconductor Thin Films
- Magnetic Properties of Alloys
- Solid-state spectroscopy and crystallography
- Organic and Molecular Conductors Research
- Luminescence and Fluorescent Materials
- Advanced Thermoelectric Materials and Devices
- Luminescence Properties of Advanced Materials
- Organic Light-Emitting Diodes Research
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Corporate Taxation and Avoidance
- Advanced Condensed Matter Physics
- Intellectual Capital and Performance Analysis
- Advanced Photocatalysis Techniques
- Nanocluster Synthesis and Applications
- Metal-Organic Frameworks: Synthesis and Applications
University of Oklahoma
2017-2025
University of Delaware
2007-2022
Norman Regional Hospital
2018-2020
Duke University
2015-2017
Oak Ridge National Laboratory
2011-2016
Naval Research Laboratory Materials Science and Technology Division
2015
Oak Ridge Associated Universities
2014
McMaster University
2014
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...
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%.
In this work, we describe details of a two-step deposition approach that enables the preparation continuous and well-structured thin films Cs2SnI6, which is one-half Sn-deficient 0-D perovskite derivative (i.e., compound can also be written as CsSn0.5I3, with structure consisting isolated SnI64– octahedra). The were characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), UV–vis spectroscopy, photoluminescence (PL),...
Application of zinc‐blende‐related chalcogenide absorbers such as CdTe and Cu(In,Ga)Se 2 (CIGSe) has enabled remarkable advancement in laboratory‐ commercial‐scale thin‐film photovoltaic performance; however concerns remain regarding the toxicity (CdTe) scarcity (CIGSe/CdTe) constituent elements. Recently, kesterite‐based Cu ZnSn(S,Se) 4 (CZTSSe) materials have emerged attractive non‐toxic earth‐abundant absorber candidates. Despite similarities between CZTSSe CIGSe/CdTe, record power...
Through density functional theory calculations, we show that the alloy perovskite system BaZr1–xTixS3 (x < 0.25) is a promising candidate for producing high power conversion efficiency (PCE) solar cells with ultrathin absorber layers. To maximize minority carrier lifetime, which important achieving PCE, defect calculations films should be synthesized under moderate (i.e., near stoichiometric) growth conditions to minimize formation of deep-level defects. The BaZrS3 also found exhibit...
Recently, interest in developing efficient, low-cost, nontoxic, and stable metal halide emitters that can be incorporated into solid-state lighting technologies has taken hold. Here we report stable, highly efficient blue-light-emitting Cs3Cu2Br5–xIx (0 ≤ x 5). Room-temperature photoluminescence measurements show bright blue emission the 456 to 443 nm range with near-unity quantum yield for Cs3Cu2I5. Density functional theory calculations power-dependent PL suggest results from self-trapped...
Zero-dimensional (0D) halides perovskites, in which anionic metal-halide octahedra (MX<sub>6</sub>)<sup>4−</sup> are separated by organic or inorganic countercations, have recently shown promise as excellent luminescent materials.
Inexpensive and highly efficient luminescent materials based on multinary halides have received increased attention in recent years. Among those considered most promising are the perovskites such as CsPbX3 because of their tunable emission through precise control chemical composition nanostructuring. However, presence toxic heavy metal Pb relatively poor stability among major challenges for introduction lead-halide-based into marketplace. Here, we report optical properties nontoxic emissive...
Low-dimensional hybrid organic–inorganic materials (HOIMs) are being widely investigated for their unique optoelectronic properties. Some of them exhibit broadband white-light (WL) luminescence upon UV excitation, providing a potential the fabrication single-component white-light-emitting diodes. Here, we report new examples low-dimensional HOIMs, based on 4-aminopyridinium (4AMP) and group 12 metals (Hg Zn), WL emission. The 4AMP cation containing structures feature HgBr4 ZnBr4 isolated...
All-inorganic and hybrid copper(I) halides have recently emerged as candidate optical materials due to their extremely high light emission efficiencies, nontoxic earth-abundant elemental compositions, low-cost solution processability. Originally inspired motivated by the research on halide perovskites family, development of emitters has been following its unique path. In this perspective, we discuss distinct low-dimensional crystal structures all-inorganic halides, which enable strong charge...
Chalcogenides such as CdTe, Cu(In,Ga)(S,Se)2 (CIGSSe), and Cu2ZnSn(S,Se)4 (CZTSSe) have enabled remarkable advances in thin-film photovoltaic performance, but concerns remain regarding (i) the toxicity (CdTe) (ii) scarcity (CIGSSe/CdTe) of constituent elements (iii) unavoidable antisite disordering that limits further efficiency improvement (CZTSSe). In this work, we show a different materials class, BaCu2SnSexS4–x (BCTSSe) system, offers prospective path to circumvent difficulties (i–iii)...
We explore the photovoltaic-relevant properties of 2D MA2Pb(SCN)2I2 (where MA = CH3NH3+) perovskite using a combination materials synthesis, characterization and density functional theory calculation, determine electronic that are significantly different from those previously reported in literature. The layered with mixed-anions exhibits an indirect bandgap ∼2.04 eV, slightly larger direct ∼2.11 eV. carriers (both electrons holes) also found to be confined within layers. Our results suggest...
Recently, copper(I) halides have been gaining increased attention as highly luminescent nontoxic alternatives to lead halide perovskites for optoelectronic applications. Here, we report preparation of blue emitting, free, all-inorganic K2CuX3 (X = Cl, Br) through five synthetic methods including traditional solid-state and solution methods. The photoluminescence (PL) emission spectra K2CuCl3 K2CuBr3 exhibit narrow peaks centered at 392 388 nm with full widths half-maximum (fwhm) values ∼54...
Abstract All‐inorganic metal halides such as Cs 4 PbX 6 and CsPbX 3 (X = Cl, Br, I) are attracting global attention owing to their promise in optoelectronic applications. However, the presence of toxic heavy lead (Pb) these materials is a major concern. Here, family nontoxic high‐efficiency blue‐emitting all‐inorganic Rb 2 CuX Br Cl) reported; compounds exhibit 1D crystal structures featuring anionic 2− ribbons separated by + cations. The measured record high photoluminescence quantum yield...
Recent work has identified a non-zinc-blende-type quaternary semiconductor, Cu2BaSnS4–xSex (CBTSSe), as promising candidate for thin-film photovoltaics (PVs). CBTSSe circumvents difficulties of competing PV materials regarding (i) toxicity (e.g., CdTe), (ii) scarcity constituent elements Cu(In,Ga)(S,Se)2/CdTe), and (iii) unavoidable antisite disordering that limits further efficiency improvement in Cu2ZnSnS4–xSex). In this work, we build on the paradigm by computationally scanning improved,...
Triplet excitons form in quasi-2D hybrid inorganic-organic perovskites and diffuse over 100 nm before radiating with >11% photoluminescence quantum efficiency (PLQE) at low temperatures.
We report the synthesis, crystal and electronic structures, as well optical properties of hybrid organic–inorganic compounds MA2CdX4 (MA = CH3NH3; X Cl, Br, I). MA2CdI4 is a new compound, whereas, for MA2CdCl4 MA2CdBr4, structural investigations have already been conducted but structures are reported here first time. Single crystals were grown through slow evaporation solutions with optimized conditions yielding mm-sized colorless (X Br) pale yellow I) crystals. variable temperature powder...
We report syntheses, crystal and electronic structures, characterization of three new hybrid organic-inorganic halides (R)ZnBr3(DMSO), (R)2CdBr4·DMSO, (R)CdI3(DMSO) (where (R) = C6(CH3)5CH2N(CH3)3, DMSO dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals bulk polycrystalline powders using a DMSO-methanol solvent system. On the basis single-crystal X-ray diffraction results carried out at room temperature 100 K, all have zero-dimensional (0D) structures...
Abstract Copper(I) halides are emerging as attractive alternatives to lead halide perovskites for optical and electronic applications. However, blue‐emitting all‐inorganic copper(I) suffer from poor stability lack of tunability their photoluminescence (PL) properties. Here, the preparation silver(I) A 2 AgX 3 (A = Rb, Cs; X Cl, Br, I) through solid‐state synthesis is reported. In contrast Cu(I) analogs, broad‐band emitters sensitive site substitutions. First‐principle calculations show that...
Low-dimensional hybrid organic–inorganic metal halides have received increased attention because of their outstanding optical and electronic properties. However, the most studied compounds contain lead long-term stability issues, which must be addressed for use in practical applications. Here, we report a new zero-dimensional halide, RInBr4, featuring photoemissive trimethyl(4-stilbenyl)methylammonium (R+) cations nonemissive InBr4– tetrahedral anions. The crystal structure RInBr4 is...
Lead-free halide light-emitting diodes (LEDs) are fabricated using nontoxic and earth-abundant CsCu2I3 with a strong yellow emission at peak wavelength of 568 nm. CsCu2I3-based host–dopant emitters formed by vacuum thermal evaporation (VTE) film codeposition process instead the commonly used solution-based deposition process. Using VTE process, extremely thin (30 nm) have successfully been dopant various organic host molecules. A bright photoluminescence quantum yield value 84.8% is achieved...
We report a new hybrid organic-inorganic Cu(I) halide, (TMS)3Cu2I5 (TMS = trimethylsulfonium), which demonstrates high efficiency and stable yellow light emission with photoluminescence quantum yield (PLQY) over 25%. The zero-dimensional crystal structure of the compound is comprised isolated face-sharing photoactive [Cu2I5]3- tetrahedral dimers surrounded by TMS+ cations. This promotes strong confinement electron-phonon coupling, leading to highly efficient from self-trapped excitons....
Abstract Highly sensitive stimuli‐responsive luminescent materials are crucial for applications in optical sensing, security, and anticounterfeiting. Here, we report two zero‐dimensional (0D) copper(I) halides, (TEP) 2 Cu Br 4 , 6 1D 3 Ag 9 which comprised of isolated [Cu ] 2− [Ag 3− polyanions, respectively, separated by TEP + (tetraethylphosphonium [TEP]) cations. demonstrate greenish‐white orange‐red emissions, with near unity photoluminescence quantum yields, while is a poor light...