A5026683905- Perovskite Materials and Applications
- Photonic and Optical Devices
- Conducting polymers and applications
- Metamaterials and Metasurfaces Applications
- Plasmonic and Surface Plasmon Research
- Neural Networks and Reservoir Computing
- Organic Electronics and Photovoltaics
- Quantum Information and Cryptography
- Nanowire Synthesis and Applications
- Quantum Dots Synthesis And Properties
- Photonic Crystals and Applications
- Optical Network Technologies
- Organic Light-Emitting Diodes Research
- Topological Materials and Phenomena
- 2D Materials and Applications
- Quantum optics and atomic interactions
- Chalcogenide Semiconductor Thin Films
- Solid-state spectroscopy and crystallography
- Luminescence and Fluorescent Materials
- Mechanical and Optical Resonators
- Phase-change materials and chalcogenides
- Advanced Fiber Laser Technologies
- Semiconductor materials and devices
- Advancements in Semiconductor Devices and Circuit Design
- Strong Light-Matter Interactions
Nanyang Technological University
2016-2025
King Abdullah University of Science and Technology
2017-2018
Centre National de la Recherche Scientifique
2012
University of California, San Diego
2007-2010
Jacobs (United States)
2007-2010
Georgia Institute of Technology
2009
Simon Fraser University
2008
University of California, Santa Barbara
2001-2007
Istituto Nazionale di Fisica Nucleare, Sezione di Pavia
2003-2007
University of Pavia
2001-2007
ZnO nanowire (NW) visible-blind UV photodetectors with internal photoconductive gain as high G ∼ 108 have been fabricated and characterized. The photoconduction mechanism in these devices has elucidated by means of time-resolved measurements spanning a wide temporal domain, from 10-9 to 102 s, revealing the coexistence fast (τ 20 ns) slow 10 s) components carrier relaxation dynamics. extremely is attributed presence oxygen-related hole-trap states at NW surface, which prevents charge-carrier...
Abstract Despite the widespread use of solution-processable hybrid organic–inorganic perovskites in photovoltaic and light-emitting applications, determination their intrinsic charge transport parameters has been elusive due to variability film preparation history-dependent device performance. Here we show that screening effects associated ionic can be effectively eliminated by lowering operating temperature methylammonium lead iodide perovskite (CH 3 NH PbI ) field-effect transistors....
Despite their extremely good performance in solar cells with efficiencies approaching 20% and the emerging application for light-emitting devices, organic–inorganic lead halide perovskites suffer from high content of toxic, polluting, bioaccumulative Pb, which may eventually hamper commercialization. Here, we present synthesis two-dimensional (2D) Cu-based hybrid study optoelectronic properties to investigate potential providing a new environmental-friendly alternative Pb. The series...
We report, for the first time, synthesis of high-quality p-type ZnO NWs using a simple chemical vapor deposition method, where phosphorus pentoxide has been used as dopant source. Single-crystal doped have their growth axis along 001 direction and form perfect vertical arrays on a-sapphire. P-type doping was confirmed by photoluminescence measurements at various temperatures studying electrical transport in single field-effect transistors. Comparisons low-temperature PL unintentionally...
Only a selected group of two-dimensional (2D) lead-halide perovskites shows peculiar broad-band photoluminescence. Here we show that the structural distortions perovskite lattice can determine defectivity material by modulating defect formation energies. By selecting and comparing two archetype systems, namely, (NBT)2PbI4 (EDBE)PbI4 (NBT = n-butylammonium EDBE 2,2-(ethylenedioxy)bis(ethylammonium)), find only latter, subject to larger deformation Pb-X bond length X-Pb-X angles, sees VF color...
The use of nanowires and nanowire structures as photodetectors is an emerging research topic. Despite the large amount reports on photoresponse that appeared in literature over last decade, mechanism leading to high photosensitivity photoconductive gain aspect ratio nanostructures has been elucidated only recently. Novel device architectures integrated single devices are also being actively studied developed. In this article, general photodetector concepts reviewed, together with a detailed...
Abstract The photoconductive properties of a novel low‐bandgap conjugated polymer, poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4 H ‐cyclopenta[2,1‐ b ;3,4‐ ′]dithiophene)‐ alt ‐4,7‐(2,1,3‐benzothiadiazole)], PCPDTBT, with an optical energy gap E g ∼ 1.5 eV, have been studied. results photoluminescence and photoconductivity measurements indicate efficient electron transfer from PCPDTBT to PCBM ([6,6]‐phenyl‐C61 butyric acid methyl ester, fullerene derivative), where acts as the donor acceptor....
Catalyst-free, direct heteroepitaxial growth of vertical InAs nanowires on Si(111) substrates was accomplished over a large area by metal−organic chemical vapor deposition. Nanowires showed very uniform diameters and zinc blende crystal structure. The heterojunctions formed at the interface between n-type p-type Si substrate were exploited to fabricate array photodiode devices which an excellent rectification ratio low reverse leakage current. Temperature-dependent current transport across...
Plasmonics is a rapidly developing field at the boundary of physical optics and condensed matter physics. It studies phenomena induced by associated with surface plasmons—elementary polar excitations bound to surfaces interfaces good nanostructured metals. This Roadmap written collectively prominent researchers in plasmonics. encompasses selected aspects nanoplasmonics. Among them are fundamental aspects, such as quantum plasmonics based on quantum-mechanical properties both underlying...
For application as a pseudocapacitor electrode, highly porous CoO nanowalls are fabricated directly on 3D macroporous nickel foam (see images). A relatively high areal capacitance is achieved because of the structure. By grafting with another pseudocapacitive oxide, can be further significantly boosted, owing to increased surface area caused by hierarchically structure well possible synergetic effect between two oxides. Detailed facts importance specialist readers published "Supporting...
We demonstrate an efficient core-shell GaAs/AlGaAs nanowire photodetector operating at room temperature. The design of this nanoscale detector is based on a type-I heterostructure combined with metal-semiconductor-metal (MSM) radial architecture, in which built-in electric fields the semiconductor heterointerface and metal/semiconductor Schottky contact promote photogenerated charge separation, enhancing photosensitivity. spectral photoconductive response shows that supports resonant optical...
Ultra-broadband photoluminescence in two-dimensional (2D) perovskites (EDBE)PbX<sub>4</sub> (where X = Cl, Br) is shown to originate from self-trapped polaronic excitons localised at specific inorganic lattice sites.
The technologies of heating, photovoltaics, water photocatalysis and artificial photosynthesis depend on the absorption light novel approaches such as coherent from a standing wave promise total dissipation energy. Extending control down to very low levels eventually single photon regime is great interest yet remains largely unexplored. Here we demonstrate photons in deeply sub-wavelength 50% absorber. We show that while travelling probabilistic, can be observed deterministically, with...
Three novel hole-conducting molecules (T101, T102 and T103) based on a triptycene core have been synthesized using short routes with high yields. The optical electrochemical properties were tuned by modifying the functional groups, through linking to diphenylamines via phenyl and/or thienyl groups. mesoporous perovskite solar cells fabricated T103 as hole transporting material (HTM) showed power conversion efficiency (PCE) of 12.24% 12.38%, respectively, which is comparable that obtained...
Structural properties closely affect the photophysical processes underlying photoluminescence broadening and white-light emission in low-dimensional perovskites.
Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to presence heavy atoms, solution-grown hybrid lead halide perovskite single exhibit short absorption length and excellent efficiency. Here we compare characteristics three-dimensional (3D) MAPbI3 MAPbBr3 two-dimensional (2D) (EDBE)PbCl4 crystals. excited thermoluminescence measurements...
Recent attempts to synthesize hybrid perovskites with large chirality have been hampered by size mismatch and weak interaction between their structure the wavelength of light. Here we adopt a planar nanostructure design overcome these limitations realize all-dielectric perovskite metasurfaces giant superstructural chirality. We identify direct spectral correspondence near- far- field chirality, tune electric magnetic multipole moments resonant chiral metamolecules obtain anisotropy factor...
Various topological laser concepts have recently enabled the demonstration of robust light-emitting devices that are immune to structural deformations and tolerant fabrication imperfections. Current realizations photonic cavities with boundaries often limited by outcoupling issues or poor directionality require complex design hinder operation at small wavelengths. Here we propose a cavity based on interface states between two one-dimensional crystals distinct Zak phases. Using few monolayers...
The authors poly(3-hexylthiophene)/[6,6]-phenyl C61-butyric acid methyl ester present a technique for modifying the internal structure of bulk heterojunction films which yields significantly improved photoconductivity. This method comprises addition alkyl thiol molecules to polymer/fullerene solution prior spin coating. Based on steady-state and transient photoconductivity measurements, photoresponsivity is an order magnitude greater than that in spun from pristine solvent; additionally,...
Ambipolar light-emitting field-effect transistors are fabricated with two different metals for the top-contact source and drain electrodes; a low-work-function metal defining channel electrode high-work-function electrode. A thin film of polypropylene-co-1-butene on SiNx is used as gate dielectric an n++-Si wafer, which functioned substrate Transport data show ambipolar behavior. Recombination electrons holes results in narrow zone light emission within channel. The location controlled by bias.
Photoinduced electron transfer in a small band gap bulk heterojunction material (see figure) is studied by ultrafast spectroscopic methods. In this composite, the photo excitation initiates from polymer to fullerene, as most materials. From analysis of carrier recombination dynamics, we infer existence an intermediate charge transferred state which long-lived mobile positive and negative carriers are generated.
Hollow core–shell nanorods with a nanogap are designed and constructed the assistance of atomic layer deposition (ALD) for energy storage applications. As demonstration, CoO NiO nanowalls enclosed by TiO2 nanotube shell, forming "wire in tube" "wall box" structures, respectively. A thin sacrificial Al2O3 is deposited ALD removed eventually, between core (or nanowall) shell. When they tested as supercapacitor electrodes, an evident difference solid nanostructure hollow ones can be found;...
We theoretically characterize the unusual white-light emission properties of two-dimensional (2D) hybrid organic–inorganic perovskites with an APbX4 structure (where A is a bidentate organic cation and X = Cl, Br). In addition to band calculations including corrections due spin–orbit couplings electron–hole interactions, computationally intensive molecular cluster approach exploited describe excitonic polaronic these 2D at atomistic level. Upon adding or removing electron from neutral...
We report a new hybrid integration scheme that offers for the first time nanowire-on-lead approach, which enables independent electrical addressability, is scalable, and has superior spatial resolution in vertical nanowire arrays. The fabrication of these arrays demonstrated to be scalable down submicrometer site-to-site spacing can combined with standard integrated circuit technologies. utilize perform electrophysiological recordings from mouse rat primary neurons human induced pluripotent...