A5020408149- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Solid-state spectroscopy and crystallography
- Conducting polymers and applications
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Porphyrin and Phthalocyanine Chemistry
- Organic Electronics and Photovoltaics
- Surface Chemistry and Catalysis
- Molecular Junctions and Nanostructures
- Organic Light-Emitting Diodes Research
- Transition Metal Oxide Nanomaterials
- Optical properties and cooling technologies in crystalline materials
- Organic and Molecular Conductors Research
- Gas Sensing Nanomaterials and Sensors
- Photochromic and Fluorescence Chemistry
- Advanced Chemical Physics Studies
- 2D Materials and Applications
- Electronic and Structural Properties of Oxides
- Crystallography and molecular interactions
- Copper-based nanomaterials and applications
- Graphene research and applications
- nanoparticles nucleation surface interactions
- Organometallic Compounds Synthesis and Characterization
University of Oxford
2016-2024
University of Sheffield
2023-2024
Clarendon College
2016-2020
Oxfam
2016-2020
University of Warwick
2016
Coventry (United Kingdom)
2016
Imperial College London
2014-2016
Science Oxford
2016
Bridge University
2016
Transnational Press London
2014-2015
Longevity has been a long-standing concern for hybrid perovskite photovoltaics. We demonstrate high-resilience positive-intrinsic-negative solar cells by incorporating piperidinium-based ionic compound into the formamidinium-cesium lead-trihalide absorber. With bandgap tuned to be well suited perovskite-on-silicon tandem cells, this piperidinium additive enhances open-circuit voltage and cell efficiency. This also retards compositional segregation impurity phases pinhole formation in...
Lead halide perovskites are materials with excellent optoelectronic and photovoltaic properties. However, some hurdles remain prior to commercialization of these materials, such as chemical stability, phase sensitivity moisture, potential issues due the toxicity lead. Here, we report a new type lead-free perovskite related compound, Cs2PdBr6. This compound is solution processable, exhibits long-lived photoluminescence, an optical band gap 1.6 eV. Density functional theory calculations...
Double perovskites have recently emerged as possible alternatives to lead-based halide for photovoltaic applications. In particular, Cs2AgBiBr6 has been the subject of several studies because its environmental stability, low toxicity, and promising optoelectronic features. Despite these encouraging features, performances solar cells based on this double perovskite are still low, suggesting severe limitations that need be addressed. work we combine experimental theoretical show short electron...
Intrinsic organic–inorganic metal halide perovskites (OIHP) based semiconductors have shown wide applications in optoelectronic devices. There been several attempts to incorporate heterovalent (e.g., Bi3+) ions the an attempt induce electronic doping and increase charge carrier density semiconductor. It has reported that inclusion of Bi3+ decreases band gap material considerably. However, contrary earlier conclusions, despite a clear change appearance crystal as observed by eye, here we show...
Abstract Perovskite solar cells have achieved the highest power conversion efficiencies on metal oxide n‐type layers, including SnO 2 and TiO . Despite ZnO having superior optoelectronic properties to these oxides, such as improved transmittance, higher conductivity, closer conduction band alignment methylammonium (MA)PbI 3 , is largely overlooked due a chemical instability when in contact with halide perovskites, which leads rapid decomposition of perovskite. While surface passivation...
We identify the limiting factors of wide bandgap metal halide perovskite solar cells. To overcome these losses, we developed an efficient optimisation strategy and outline necessary steps for continued development perovskites.
In this work, we couple theoretical and experimental approaches to understand reduce the losses of wide bandgap Br-rich perovskite pin devices at open-circuit voltage (VOC) short-circuit current (JSC) conditions. A mismatch between internal quasi-Fermi level splitting (QFLS) external VOC is detrimental for these devices. We demonstrate that modifying top-surface with guanidinium-Br imidazolium-Br forms a low-dimensional phase n-interface, suppressing QFLS-VOC mismatch, boosting VOC....
By correlating photovoltaic and material properties with metal content, we identify compositional ranges of low high optoelectronic quality in (FA<sub>0.83</sub>Cs<sub>0.17</sub>)(Pb<sub>1−y</sub>Sn<sub>y</sub>)I<sub>3</sub> perovskites.
Light-emitting diodes (LEDs) made from metal halide perovskites have demonstrated external electroluminescent quantum efficiencies (EQEEL) in excess of 20%. However, their poor operational stability, resulting lifetimes only tens to hundreds hours, needs be dramatically improved prior commercial use. There is little consensus the community upon which factors limit stability these devices. Here, we investigate role played by ammonium cations on stability. We vary amount phenylethylammonium...
As perovskite-based photovoltaics near commercialization, it is imperative to develop industrial-scale defect-passivation techniques. Vapor deposition a solvent-free fabrication technique that widely implemented in industry and can be used fabricate metal-halide perovskite thin films. We demonstrate markably improved growth optoelectronic properties for vapor-deposited [CH(NH2)2]0.83Cs0.17PbI3 solar cells by partially substituting PbI2 PbCl2 as the inorganic precursor. find partial...
Abstract Semiconducting lead halide perovskite nanocrystals (PNCs) are regarded as promising candidates for next‐generation optoelectronic devices due to their solution processability and outstanding properties. While the field of light‐emitting diodes (LEDs) photovoltaics (PVs), two prime examples devices, has recently seen a multitude efforts toward high‐performance PNC‐based realizing both with high efficiencies stabilities through single PNC processing strategy remained challenge. In...
Formamidinium lead triiodide (FAPbI3) is the leading candidate for single-junction metal-halide perovskite photovoltaics, despite metastability of this phase. To enhance its ambient-phase stability and produce world-record photovoltaic efficiencies, methylenediammonium dichloride (MDACl2) has been used as an additive in FAPbI3. MDA2+ reported incorporated into lattice alongside Cl-. However, precise function role remain uncertain. Here, we grow FAPbI3 single crystals from a solution...
Fully textured perovskite silicon tandem solar cells are promising for future low-cost photovoltaic deployment. However, the fill factor and open-circuit voltage of these devices currently limited by high density defects at grain boundaries interfaces with charge transport layers. To address this, we devise a strategy to simultaneously enhance crystallization passivate perovskite/C60 interface. By incorporating urea (CO(NH2)2) as an additive in solution step hybrid evaporation/spin-coating...
Charge transport layers strongly influence the performance of perovskite solar cells (PSCs). To date, compact and mesoporous scaffolds titanium dioxide have emerged as good electron (ETL), enabling record power conversion efficiencies (PCE). However, these ETLs require sintering above 400 °C, which excludes them from low-temperature applications such flexible devices silicon-heterojunction tandems. Furthermore, instability TiO2 under prolonged exposure to sunlight appears be a critical...
Abstract Metal‐halide perovskites (MHP) are highly promising semiconductors for light‐emitting and photovoltaic applications. The colloidal synthesis of nanocrystals (NCs) is an effective approach obtaining nearly defect‐free MHP that can be processed into inks low‐cost, high‐performance device fabrication. However, disentangling the effects surface ligands, morphology, boundaries on charge‐carrier transport in thin films fabricated with these high‐quality NCs inherently difficult. To...
Vacuum deposition is a solvent-free method suitable for growing thin films of metal halide perovskite (MHP) semiconductors. However, most reports high-efficiency solar cells based on such vacuum-deposited MHP incorporate solution-processed hole transport layers (HTLs), thereby complicating prospects industrial upscaling and potentially affecting the overall device stability. In this work, we investigate organometallic copper phthalocyanine (CuPc) zinc (ZnPc) as alternative, low-cost, durable...
Abstract Two dimensional/three‐dimensional (2D/3D) metal halide perovskite heterostructures have attracted great interest in photovoltaic and light‐emitting diode (LEDs) applications. In both, their implementation results an improvement device efficiency yet the understanding of these remains incomplete. this work role organic cations, essential for formation 2D structures is unraveled, a range heterostructures. These are used to fabricate efficient green LEDs strong dependence between...
Abstract Quaternary copper‐silver‐bismuth‐iodide compounds represent a promising new class of wide‐bandgap (2 eV) semiconductors for photovoltaic and photodetector applications. In this study, vapor phase co‐evaporation is utilized to fabricate Cu 2 AgBiI 6 thin films devices. The findings show that the properties vapor‐deposited are highly dependent upon processing temperature, exhibiting increased pinhole density transforming into mixture quaternary, binary, metallic phases depending on...
We propose a computational methodology that highlights the intimate connection between surface and interface dipoles work functions or valence band alignments. apply to inspect energy level alignments of halide perovskites considering: (i) effect termination ability fine-tune interpret shift in via (ii) coating (iii) functionalization and/or passivation with molecules. highlight importance local strain relaxation at surfaces interfaces revisit classical approaches based on capacitor models....
Halide perovskite light-emitting diodes (PeLEDs) exhibit great potential for use in next-generation display technologies. However, scale-up will be challenging due to the requirement of very thin transport layers high efficiencies, which often present spatial inhomogeneities from improper wetting and drying during solution processing. Here, we show how a Al2O3 layer grown by atomic deposition can used preferentially cover regions imperfect hole form an intermixed composite with organic...
Cesium lead triiodide (CsPbI3) is an attractive material for photovoltaic applications due to its appropriate band gap, strong optical absorption, and high thermal stability. However, the perovskite phase suffers from moisture induced structural instability. Previous studies have utilized a range of solvent systems establish role choice in instabilities. Despite this, effects different solvents on electronic structure this not been compared. We report substantial chemical compositional...