A5012925335- Perovskite Materials and Applications
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Solid-state spectroscopy and crystallography
- Conducting polymers and applications
- Organic and Molecular Conductors Research
- 2D Materials and Applications
- Advancements in Battery Materials
- Optical properties and cooling technologies in crystalline materials
- Semiconductor materials and devices
- Organic Light-Emitting Diodes Research
- Silicon and Solar Cell Technologies
- Fuel Cells and Related Materials
- Catalytic Processes in Materials Science
- TiO2 Photocatalysis and Solar Cells
- Congenital gastrointestinal and neural anomalies
- Electronic and Structural Properties of Oxides
- Graphene research and applications
- Gastroesophageal reflux and treatments
- Gas Sensing Nanomaterials and Sensors
- Gastrointestinal motility and disorders
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Battery Technologies Research
Argonne National Laboratory
2016-2020
University of Utah
2019
Northwestern University
2014-2018
King Abdulaziz University
2014
We report on the fabrication and properties of semiconducting 2D (CH3(CH2)3NH3)2(CH3NH3)(n-1)Pb(n)I(3n+1) (n = 1, 2, 3, 4) perovskite thin films. The band gaps series decrease with increasing n values, from 2.24 eV (CH3(CH2)3NH3)2PbI4 1) to 1.52 CH3NH3PbI3 ∞). compounds exhibit strong light absorption in visible region, accompanied by photoluminescence at room temperature, rendering them promising absorbers for photovoltaic applications. Moreover, we find that films semi-2D perovskites...
The hybrid two-dimensional (2D) halide perovskites have recently drawn significant interest because they can serve as excellent photoabsorbers in perovskite solar cells. Here we present the large scale synthesis, crystal structure, and optical characterization of 2D (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 (n = 1, 2, 3, 4, ∞) perovskites, a family layered compounds with tunable semiconductor characteristics. These materials consist well-defined inorganic layers intercalated bulky butylammonium...
Tin-based halide perovskite materials have been successfully employed in lead-free solar cells, but the tendency of these to form leakage pathways from p-type defect states, mainly Sn4+ and Sn vacancies, causes poor device reproducibility limits overall power conversion efficiencies (PCEs). Here, we present an effective process that involves a reducing vapor atmosphere during preparation Sn-based cells solve this problem, using MASnI3, CsSnI3, CsSnBr3 as representative absorbers. This...
Low electrical resistivity (high dark carrier concentration) of CH3NH3SnI3 often leads to short-circuiting in solar cells, and appropriate thin-film modifications are required ensure functional devices. The long-term durability organic–inorganic perovskite cells necessitates the protection thin films from moisture prevent material decomposition. Herein, we report that stability two-dimensional (2D) Ruddlesden–Popper (CH3(CH2)3NH3)2(CH3NH3)n−1SnnI3n+1 perovskites considerably improved...
The development of Sn-based perovskite solar cells has been challenging because devices often show short-circuit behavior due to poor morphologies and undesired electrical properties the thin films. A low-temperature vapor-assisted solution process (LT-VASP) employed as a novel kinetically controlled gas-solid reaction film fabrication method prepare lead-free CH3NH3SnI3 We that solid SnI2 substrate temperature is key parameter in achieving films with high surface coverage excellent...
In the fast-evolving field of halide perovskite semiconductors, 2D perovskites (A')2(A) n-1M n X3n+1 [where A = Cs+, CH3NH3+, HC(NH2)2+; A' ammonium cation acting as spacer; M Ge2+, Sn2+, Pb2+; and X Cl-, Br-, I-] have recently made a critical entry. The value defines thickness layers, which controls optical electronic properties. demonstrated preliminary optoelectronic device lifetime superior to their 3D counterparts. They also attracted fundamental interest solution-processed quantum...
Perovskite-containing solar cells were fabricated in a two-step procedure which PbI2 is deposited via spin-coating and subsequently converted to the CH3NH3PbI3 perovskite by dipping solution of CH3NH3I. By varying time from 5 s 2 h, we observe that device performance shows an unexpectedly remarkable trend. At times below 15 min current density voltage are enhanced 10.1 mA/cm2 933 mV (5 s) 15.1 1036 (15 min). However, upon further conversion, decreases 9.7 846 after h. Based on X-ray...
The optoelectronic properties of hybrid perovskites can be easily tailored by varying their components. Specifically, mixing the common short organic cation (methylammonium (MA)) with a larger one (e.g., butyl ammonium (BA)) results in 2-dimensional thicknesses inorganic layers separated large cation. In both these applications, detailed understanding dissociation and recombination electron–hole pairs is prime importance. this work, we give clear experimental demonstration interconversion...
A low hole carrier concentration in methylammonium tin halide (MASnX3) perovskite semiconductors is a prerequisite for nonshorting solar cell device. In-depth film characterizations were performed on MASnI3–xBrx films, fabricated by both low-temperature vapor-assisted solution process (LT-VASP) and conventional one-step methods, to reveal the origin of lower from films former approach. We found that vaporization CH3NH3I solid at 150 °C, temperature which LT-VASP occurs, does not supply...
Despite rapid advances in conversion efficiency (>22%), the environmental stability of perovskite solar cells remains a substantial barrier to commercialization. Here, we show significant improvement inverted against liquid water and high operating temperature (100 °C) by integrating an ultrathin amorphous oxide electron extraction layer via atomic deposition (ALD). These unencapsulated devices exhibit stable operation over at least 10 h when subjected thermal stress ambient environments, as...
A low-temperature (<120 °C) route to pinhole-free amorphous TiO2 compact layers may pave the way more efficient, flexible, and stable inverted perovskite halide device designs. Toward this end, we utilize thermal atomic layer deposition (ALD) synthesize ultrathin (12 nm) underlayers for planar PV. Although performance with as-deposited films is poor, identify room-temperature UV–O3 treatment as a efficiency comparable crystalline thin synthesized by higher temperature methods. We further...
Organic–inorganic hybrid halide perovskites are a promising class of materials for photovoltaic application with reported power efficiencies over ∼22%. However, not much is known about the influence organic dipole rotation and phase transitions on charge carrier dynamics. Here, we report substantial changes in mobility lifetime carriers CH3NH3PbI3 after low-temperature tetragonal (β) to orthorhombic (γ) transition. By using microwave conductivity measurements, observed that ionized increase...
Impurities in semiconductors, for example, lead-based hybrid perovskites, have a major influence on their performance as photovoltaic (PV) light absorbers. While impurities could create harmful trap states that lead to nonradiative recombination of charge carriers and adversely affect PV efficiency, they also potentially increase absorption via midgap energy levels act stepping stones subgap photons or introduce doping. To unearth trends impurity states, we use first principles density...
ADVERTISEMENT RETURN TO ISSUEPREVViewpointNEXTIntroducing Perovskite Solar Cells to UndergraduatesSameer Patwardhan*, Duyen H. Cao, Shelby Hatch, Omar K. Farha, Joseph T. Hupp, Mercouri G. Kanatzidis, and George C. Schatz*View Author Information Argonne−Northwestern Energy Research (ANSER) Center Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States*E-mail: [email protected] (S.P.).*E-mail: (G.C.S.).Cite this: J. Phys. Chem. Lett. 2015, 6, 2,...
Abstract Organic-inorganic hybrid perovskites such as methylammonium lead iodide (CH 3 NH PbI ) are game-changing semiconductors for solar cells and light-emitting devices owing to their defect tolerance exceptionally long carrier lifetimes diffusion lengths. Determining whether the dynamically disordered organic cations with large dipole moment benefit optoelectronic properties of CH has been an outstanding challenge. Herein, via transient absorption measurements employing infrared pump...
We computationally design and experimentally corroborate the atomic layer deposition (ALD) of metal oxides with tailorable nucleation on selected self-assembled monolayers (SAMs) decorated terminal functional groups. The low-temperature ALD processes for Al2O3, MnO, especially ZnO are inhibited nonpolar alkyl-terminated SAMs high efficacy, in agreement thermodynamics calculated reactivity as well potentially physisorbed precursors. Functional-SAM surfaces also considered uniform oxides,...
Abstract Hybrid organic–inorganic perovskites such as methylammonium lead iodide have emerged promising semiconductors for energy‐relevant applications. The interactions between charge carriers and lattice vibrations, giving rise to polarons, been invoked explain some of their extraordinary optoelectronic properties. Here, time‐resolved optical spectroscopy is performed, with off‐resonant pumping electronic probing, examine several representative perovskites. temporal oscillations bandgaps...
Lead halide perovskites present a versatile class of solution-processable semiconductors with highly tunable bandgaps that span ultraviolet, visible, and near-infrared portions the spectrum. We explore phase-separated chloride iodide lead perovskite mixtures as candidate materials for intermediate band applications in future photovoltaics. X-ray diffraction scanning electron microscopy reveal deposition precursor solutions across MAPbCl3/MAPbI3 composition space affords quasi-epitaxial...
Fifty atomic layer deposition (ALD) cycles of trimethylaluminum and water were applied to single-layer graphene on copper Nafion membranes that result in alumina coatings fully block photoelectron emission from the underlying substrate materials (copper Nafion, respectively). This finding is consistent with relatively uninhibited ALD nucleation growth a thickness ∼5 nm further suggests continuous no uncoated regions exposed. The ALD-derived are good barriers large ions, e.g., aqueous ferric...
Intrinsic and extrinsic defects play a major role in determining solar cell efficiencies of lead halide hybrid perovskite absorbers. Here, we present the results first-principles computations performed on MAPbBr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (MA= methylammonium) to study energetics defect levels intrinsic point defects, namely vacancy, self-interstitial anti -site, Pbsubstitution defects. While vacancies are lowest...
Titanium dioxide (TiO 2 ) thin films have been utilized in a wide range of applications optoelectronics and solar energy conversion. In particular, TiO has exclusively used photovoltaic devices photoelectrochemical cells owing to its ability efficiently transport electrons passivate photoactive materials against aqueous media. However, exhibits optimal properties the crystalline anatase phase, thus requires high temperature annealing, which significantly limits application sensitive...
Titanium dioxide (TiO 2 ) thin films have been utilized in a wide range of applications optoelectronics and solar energy conversion. In particular, TiO has exclusively used photovoltaic (PV) devices photoelectrochemical (PEC) cells owing to its ability efficiently transport electrons passivate photoactive materials against aqueous media. However, exhibits optimal properties the crystalline anatase phase, thus requires high temperature annealing step at 500 °C, which significantly limits...