A5087270945- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Conducting polymers and applications
- Organic Electronics and Photovoltaics
- Solid-state spectroscopy and crystallography
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Advanced Photocatalysis Techniques
- Graphene research and applications
- Fullerene Chemistry and Applications
- Organic and Molecular Conductors Research
- Optical properties and cooling technologies in crystalline materials
- Advanced Memory and Neural Computing
- Organic Light-Emitting Diodes Research
- Advancements in Solid Oxide Fuel Cells
- Advanced Nanomaterials in Catalysis
- 2D Materials and Applications
- Renal function and acid-base balance
- Supercapacitor Materials and Fabrication
- Hemodynamic Monitoring and Therapy
- Advanced Sensor and Energy Harvesting Materials
- ZnO doping and properties
- TiO2 Photocatalysis and Solar Cells
- Crystal Structures and Properties
University of Oxford
2013-2024
SLAC National Accelerator Laboratory
2023
National Renewable Energy Laboratory
2023
Monash University
2023
Center for Nano Science and Technology
2015-2022
Italian Institute of Technology
2015-2022
Clarendon College
2014-2020
Oxfam
2018-2020
Mylan (Switzerland)
2015-2018
Mylan (South Africa)
2017
Perovskite solar cells have rapidly risen to the forefront of emerging photovoltaic technologies, exhibiting rising efficiencies. This is likely continue rise, but in development these there are unusual characteristics that arisen, specifically an anomalous hysteresis current-voltage curves. We identify this phenomenon and show some examples factors make more or less extreme. also demonstrate stabilized power output under working conditions suggest a useful parameter present, alongside scan...
We have reduced the processing temperature of bulk absorber layer in CH3NH3PbI3−xClx perovskite solar cells from 500 to <150 °C and achieved power conversion efficiencies up 12.3%. Remarkably, we find that devices with planar thin-film architecture, where ambipolar transports both holes electrons, convert absorbed photons into collected charge close 100% efficiency.
It has been proposed that organic-inorganic perovskites may provide the ``disruptive'' technology needed to deliver widespread and affordable solar power. To reach this goal, a detailed understanding of their material properties behavior in working devices is needed. The authors present robust model explains charge recombination presence subgap trap states these materials. This study provides concrete predictions regarding most important parameters for improved solar-cell performance perovskites.
The highest efficiencies in solution-processable perovskite-based solar cells have been achieved using an electron collection layer that requires sintering at 500 °C. This is unfavorable for low-cost production, applications on plastic substrates, and multijunction device architectures. Here we report a low-cost, solution-based deposition procedure utilizing nanocomposites of graphene TiO2 nanoparticles as the layers meso-superstructured perovskite cells. nanoflakes provide superior...
Perovskite cells benefit from a good night's sleep.
We report the low-frequency resonant Raman spectrum of methylammonium lead-iodide, a prototypical perovskite for solar cells applications, on mesoporous Al2O3. The measured assignment is assisted by DFT simulations spectra suitable periodic and model systems. bands at 62 94 cm(-1) are assigned respectively to bending stretching Pb-I bonds, thus diagnostic modes inorganic cage. also assign librations organic cations 119 154 cm(-1). broad, unstructured 200-400 features torsional mode cations,...
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...
Electron/hole traps related to interstitial iodine defects show the typical features of photo-electrochemistry, inducing MAPbI<sub>3</sub> defect tolerance.
We report optical measurements on MAPbI<sub>3</sub>solar cells, together with<italic>ab initio</italic>simulations, to investigate the material property changes across tetragonal cubic phase transition.
Thorough measurements of the optical constants CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>are used to determine limiting parasitic losses in solar cells revealing up 100% IQE and excellent performance at oblique incidence.
We show that trapped electrons recombine with free holes unexpectedly slowly, on microsecond time scales, relaxing the limit obtainable open circuit voltage.
Space-charge-limited current (SCLC) measurements have been widely used to study the charge carrier mobility and trap density in semiconductors. However, their applicability metal halide perovskites is not straightforward, due mixed ionic electronic nature of these materials. Here, we discuss pitfalls SCLC for perovskite semiconductors, especially effect mobile ions. We show, using drift-diffusion (DD) simulations, that ions strongly affect measurement usual analysis interpretation need be...
Solution-processed organometal trihalide perovskite solar cells are attracting increasing interest, leading to high performances over 15% in thin film architectures. Here, we probe the presence of sub gap states both solid and mesosuperstructured films determine that they strongly influence photoconductivity response splitting quasi-Fermi levels cells. We find while planar superior terms charge carrier mobility (in excess 20 cm(2) V(-1) s(-1)) emissivity, heterojunction limited photovoltage...
The loss from halide-segregation in wide bandgap perovskite solar cells is quantified, revealing that the performance bottleneck currently is, fact, non-radiative recombination.
Metal halide perovskite semiconductors have sprung to the forefront of research into optoelectronic devices and materials, largely because their remarkable photovoltaic efficiency records above 25% in single-junction 28% tandem solar cells, achieved within a decade research. Despite this rapid progress, ionic conduction semiconductor still puzzles community can significant impact on all metal perovskite-based its influence upon electronic processes. This phenomenon thus also makes...
For lead halide perovskite solar cells to be considered for large‐scale commercial applications, the active material must proven fundamentally stable under relevant operating conditions, such as exposure light, heat, ambient environment, and electrical bias. Reversible irreversible effects upon applying an electric field different environmental conditions are identified. The application of in inert leads only a reversible poling on time scale minutes, whose distribution is mapped throughout...
Organic–inorganic metal halide perovskite solar cells have emerged in the past few years to promise highly efficient photovoltaic devices at low costs. Here, temperature‐sensitive core–shell Ag@TiO 2 nanoparticles are successfully incorporated into through a low‐temperature processing route, boosting measured device efficiencies up 16.3%. Experimental evidence is shown and theoretical model developed which predicts that presence of polarizable enhances radiative decay excitons increases...
Charge extracting layers play a key role in the elimination of hysteresis from J–V characteristics inverted hybrid perovskite solar cells. Methanofullerene electron stabilize short-circuit photocurrents very first scan, while preconditioning cycles are needed to open-circuit voltage owing interaction between migrating iodide ions and charge extraction layer. As service our authors readers, this journal provides supporting information supplied by authors. Such materials peer reviewed may be...
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....
Abstract Charge carrier mobility is a fundamental property of semiconductor materials that governs many electronic device characteristics. For metal halide perovskites, wide range charge mobilities have been reported using different techniques. Mobilities are often estimated via transient methods assuming an initial population after pulsed photoexcitation and measurement photoconductivity non-contact or contact nanosecond to millisecond methods, early-time recombination...