A5081383102- Perovskite Materials and Applications
- Conducting polymers and applications
- Organic Electronics and Photovoltaics
- Chalcogenide Semiconductor Thin Films
- Organic Light-Emitting Diodes Research
- Thin-Film Transistor Technologies
- solar cell performance optimization
- Quantum Dots Synthesis And Properties
- Solid-state spectroscopy and crystallography
- Advanced optical system design
- Force Microscopy Techniques and Applications
- Electrowetting and Microfluidic Technologies
- Polymer crystallization and properties
- X-ray Diffraction in Crystallography
- Carbon Nanotubes in Composites
- Silicon and Solar Cell Technologies
- Electron and X-Ray Spectroscopy Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Ethics and Social Impacts of AI
- Optical properties and cooling technologies in crystalline materials
- Advanced X-ray Imaging Techniques
- Near-Field Optical Microscopy
- Adaptive optics and wavefront sensing
- Optical Wireless Communication Technologies
- Transition Metal Oxide Nanomaterials
University of Sheffield
2016-2020
Sheffield City Council
2019
Masdar Institute of Science and Technology
2013-2015
Institute of Science and Technology
2014
Sadjad University of Technology
2014
Cardiff University
2010-2013
Siemens (Germany)
2011
Halide perovskites are found to exhibit strain patterns over large areas, which influences the lifetimes of charge carriers.
Abstract Crystallization and phase segregation during thermal annealing lead to the increase of power‐conversion efficiency in poly(3‐hexylthiophene) (P3HT):[6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) bulk‐heterojunction solar cells. An understanding length time scale on which crystallization occur is important improve control nanomorphology. monitored by means grazing incidence X‐ray diffraction real annealing. Furthermore, change film density ellipsometry evolution carrier mobilities...
A real-time crystallographic analysis of P3HT/PCBM films during thermal annealing is reported, detailing the temporal variation crystallization, disorder, and orientational spread annealing. Five chlorobenzene solutions with different P3HT concentrations (0, 33, 50, 67, 100 wt %) were spin coated on SiO2 substrates. The thick (∼100 nm) studied (50 min at 140 °C), in situ synchrotron grazing incidence X-ray diffraction (GI-XRD) a sampling time <8 s. For first time, evolution crystal structure...
The power conversion efficiency in a conjugated polymer-functionalized fullerene bulk heterojunction organic photovoltaic (OPV) device is dependent both on the electronic properties of constituent materials and nanoscale morphology active semiconductor layer thin-film. Here we use situ ellipsometry grazing incidence X-ray scattering (GI-XS) to study molecular self-organization poly(3-hexylthiophene) (P3HT) [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend films real time, during drying...
We report significant improvements in the optoelectronic properties of lead halide perovskites with addition monovalent ions ionic radii close to Pb2+. investigate chemical distribution and electronic structure solution processed CH3NH3PbI3 perovskite structures containing Na+, Cu+, Ag+, which are lower valence metal than Pb2+ but have similar radii. Synchrotron X-ray diffraction reveals a pronounced shift main peaks for cation-based films, suggesting incorporation these cations into lattice...
In the last years there has been a renewed interest for zinc oxide semiconductor, mainly triggered by its prospects in optoelectronic applications. particular, thin films are being widely used photovoltaic applications, which determination of electrical conductivity is great importance. Being an intrinsically doped material, quantification doping concentration always challenging. Here we show how to probe charge carrier density Scanning Kelvin Probe Microscopy, technique that allows...
This publication investigates the microstructure of high electron mobility polymer poly([N,N′-bis(2-octyldodecyl)-11 naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-12 biothiopene)) (P(NDI2OD-T2)) using a combination grazing incidence X-ray diffraction (GIXD), near-edge absorption fine structure (NEXAFS), and optical spectroscopies. GIXD measurements confirm extended in-plane lamellae ordering out-of-plane π−π stacking. Angle-resolved surface-sensitive NEXAFS measurements,...
Herein we address the factors controlling photocurrent generation in P3HT:PCBM blend films as a function of composition and annealing treatment. Absorption, photoluminescence, transient absorption spectroscopy are used to distinguish role exciton dissociation, charge pair separation, collection. Variations film microstructure with treatment studied using X-ray diffraction. While trend [Muller, et al., Adv. Mater. 2008, 20, 3510] does not follow it closely follows generation. Moreover,...
Metal-halide perovskites show remarkably clean semiconductor behaviour, as evidenced by their excellent solar cell performance, in spite of the presence many structural and chemical defects. Here, we how this performance sets during earliest phase conversion from metal salts organic-based precursors solvent, using simultaneous situ synchrotron X-ray operando current–voltage measurements on films prepared interdigitated back-contact substrates. These structures function working cells soon...
Grazing incidence wide and small angle X‐ray scattering (GIWAXS GISAXS) measurements have been used to study the crystallization kinetics of organolead halide perovskite CH 3 NH PbI 3– x Cl during thermal annealing. In situ GIWAXS recorded annealing are characterize quantify transition from a crystalline precursor structure. GISAXS indicate an evolution crystallite sizes annealing, with number crystallites having between 30 400 nm increasing through process. Using ex scanning electron...
Abstract The effect of the addition 1,8‐octanedithiol (ODT) during processing on microstructure blend films poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene)‐ alt ‐4,7(2,1,3‐benzothiadiazole)] (PCPDTBT) and [6,6]‐phenyl‐C 71 butyric acid methyl ester ([70]PCBM) is studied. Grazing incidence X‐ray diffraction absorption spectroscopy show that crystalline order PCPDTBT increases when ODT introduced in solution phase either to neat polymer systems or blends with [70]PCBM....
Abstract We explore the degradation behaviour under continuous illumination and direct oxygen exposure of inverted unencapsulated formamidinium(FA) 0.83 Cs 0.17 Pb(I 0.8 Br 0.2 ) 3 , CH NH PbI 3−x Cl x perovskite solar cells. continuously test devices in-situ in-operando with current-voltage sweeps, transient photocurrent, photovoltage measurements, find that in cells due to occurs over shorter timescales than FA mixed-cation devices. attribute these oxygen-induced losses power conversion...
We use grazing-incidence wide-angle X-ray scattering (GIWAXS) and molecular modeling to understand the difference in crystallization of several cyclopentadithiophene–benzothiadiazole polymer derivatives. observe using GIWAXS that when carbon bridging atom is substituted by a silicon atom, π–π stacking distance decreased while lamellar increased. Using modeling, we calculate potential energy surfaces an ordered array oligomers as function distances find two local minima for both analogues....
Synchrotron grazing incidence WAXS is used to track CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> precursor and perovskite crystallites rotation <italic>in situ</italic> during solution-deposition thermal annealing.
Scanning nanofocus X-ray diffraction (nXRD) performed at a synchrotron is used for the first time to simultaneously probe morphology and structural properties of spin-coated CH3NH3PbI3 (MAPI) perovskite films photovoltaic devices. MAPI are on Si/SiO2/PEDOT:PSS substrate held different temperatures during deposition in order tune film coverage, then investigated by nXRD, scanning electron microscopy (SEM) grazing incidence wide angle scatter-ing (GI-WAXS). The advantages nXRD over SEM GI-WAXS...
The self-assembly behaviour, structure, and consequently the electronic properties of electroactive organic molecules can differ significantly from those bulk material when confined to thin films. Here we have examined self-organised in-plane out-of-plane structures aniline oligomers in films using surface-sensitive grazing-incidence X-ray scattering (GIXS). Thin tetramer (TANI) octamer (OANI) were prepared both their native emeraldine base (EB) oxidation state doped salt (ES) (combined with...
The growth-kinetics of PCBM crystals, on two different length-scales, is controlled by the thickness polymer layer within a PCBM–polymer bilayer.
Abstract Grazing incidence X‐ray diffraction (GI‐XRD) is used to characterize the crystallographic dynamics of low molecular weight (LMW) and high (HMW) poly(3‐hexylselenophene) (P3HS) films blend P3HS with [6‐6‐]‐phenyl‐C 61 ‐butyric acid methyl ester (PCBM) as a function ‘step‐by‐step’ thermal annealing, from room temperature 250 °C. The temperature‐dependent GIXRD data show how melting point crystallites decreased by presence PCBM. crystallite domain sizes dramatically increase upon...
We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of contact potential difference and second derivative capacitance between tip sample, along with height information. only required equipment consists microscope lift-mode EFM capable phase shift detection. designate this approach as Scanning Probe Potential (SPP-EFM). An open-source MATLAB Graphical User Interface...
Henry J. Snaith is Professor of Physics in the Clarendon Laboratory at University Oxford and Fellow Royal Society. He has pioneered field perovskite solar cells published more than 300 papers. founder Chief Scientist Officer Photovoltaics, which holds largest patent portfolio worldwide focuses on developing commercialising PV technology. In this interview, he discusses present status future prospects PV. The interview available https://youtu.be/sbe9Z5oEs5o.
The incorporation of noble metal nanoparticles, displaying localized surface plasmon resonance, in the active area donor-acceptor bulk-heterojunction organic photovoltaic devices is an industrially compatible light trapping strategy, able to guarantee better absorption incident photons and give efficiency improvement between 12% 38%. In present work, we investigate effect Au Ag nanoparticles blended with P3HT: PCBM on P3HT crystallization dynamics by synchrotron grazing incidence X-ray...