ORCID Profile
0000-0002-0149-9128
Current Organisation
Nanyang Technological University
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Publisher: Wiley
Date: 03-09-2015
Abstract: A novel hole‐transporting molecule (F101) based on a furan core has been synthesized by means of a short, high‐yielding route. When used as the hole‐transporting material (HTM) in mesoporous methylammonium lead halide perovskite solar cells (PSCs) it produced better device performance than the current state‐of‐the‐art HTM 2,2′,7,7′‐tetrakis‐( N , N ‐di‐ p ‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD). The F101‐HTM‐based device exhibited both slightly higher J sc (19.63 vs. 18.41 mA cm −2 ) and V oc (1.1 vs. 1.05 V) resulting in a marginally higher power conversion efficiency (PCE) (13.1 vs. 13 %). The steady‐state and time‐resolved photoluminescence show that F101 has significant charge extraction ability. The simple molecular structure, short synthesis route with high yield and better performance in devices makes F101 an excellent candidate for replacing the expensive spiro‐OMeTAD as HTM in PSCs.
Publisher: Elsevier BV
Date: 04-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA01776B
Abstract: A power conversion efficiency of 11% has been obtained from a perovskite solar cell using a new silafluorene-based hole transporting material made by a short efficient synthesis.
Publisher: Wiley
Date: 10-06-2021
Abstract: Solution‐processed hybrid organic–inorganic perovskite light‐emitting transistors (PeLETs) suffer from low brightness and environmental instability induced by temperature‐activated trapping, ionic motion, and polarization effects, which so far have been hindering the realization of devices operating at room temperature. Here high quality thermally co‐evaporated methylammonium lead iodide perovskite films are employed to minimize ionic motion and significantly improve the electroluminescence characteristics of the perovskite active layer, enabling stable device operation up to ≈ 310 K. The demonstration of PeLETs operating at and beyond room‐temperature paves the way for practical applications in the rapidly evolving area of solid‐state lighting, active‐matrix displays, and visible light communications.
Publisher: AIP Publishing
Date: 02-11-2012
DOI: 10.1063/1.4766279
Abstract: We report on the tunable photovoltaic effect of self-doped single-crystal SrTiO3 (STO), a prototypical perovskite-structured complex oxide, and evaluate its performance in Schottky junction solar cells. The photovaltaic characteristics of vacuum-reduced STO single crystals are dictated by a thin surface layer with electrons donated by oxygen vacancies. Under UV illumination, a photovoltage of 1.1 V is observed in the as-received STO single crystal, while the s le reduced at 750 °C presents the highest incident photon to carrier conversion efficiency. Furthermore, in the STO/Pt Schottky junction, a power conversion efficiency of 0.88% was achieved under standard AM 1.5 illumination at room temperature. This work establishes STO as a high-mobility photovoltaic semiconductor with potential of integration in self-powered oxide electronics.
Publisher: OSA
Date: 2016
Publisher: American Chemical Society (ACS)
Date: 16-11-2022
Publisher: American Chemical Society (ACS)
Date: 07-09-2017
Publisher: American Chemical Society (ACS)
Date: 02-05-2023
Publisher: Wiley
Date: 09-11-2016
Publisher: Wiley
Date: 22-11-2022
Abstract: Metasurfaces supporting optical bound states in the continuum (BICs) are emerging as simple and compact optical cavities to realize polarization-vortex lasers. The winding of the polarization around the singularity defines topological charges which are generally set by the cavity design and cannot be altered without changing geometrical parameters. Here, a subwavelength-thin phase-change halide perovskite BIC metasurface functioning as a tunable polarization vortex microlaser is demonstrated. Upon the perovskite structural phase transitions, both its refractive index and gain vary substantially, inducing reversible and bistable switching between distinct polarization vortexes underpinned by opposite topological charges. Dynamic tuning and switching of the resulting vector beams may find use in microscopy imaging, particle trapping and manipulation, and optical data storage.
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEO_SI.2020.SF3F.5
Abstract: We report the first dielectric perovskite metasurfaces with continuously tenable optical response across the visible spectmm via a small temperatere gradient around room temperature, bearing potential applications in active light-emitting devices and spatial-light-modulators.
Publisher: Royal Society of Chemistry (RSC)
Date: 15-05-2014
DOI: 10.1039/C4SC00814F
Publisher: Wiley
Date: 25-07-2023
Abstract: Unbalanced mobility and injection of charge carriers in metal‐halide perovskite light‐emitting devices pose severe limitations to the efficiency and response time of the electroluminescence. Modulation of gate bias in methylammonium lead iodide light‐emitting transistors has proven effective in increasing the brightness of light emission up to MHz frequencies. In this work, a new approach is developed to improve charge carrier injection and enhance electroluminescence of perovskite light‐emitting transistors by independent control of drain–source and gate–source bias voltages to compensate for space‐charge effects. Optimization of bias pulse synchronization induces a fourfold enhancement of the emission intensity. Interestingly, the optimal phase delay between biasing pulses depends on modulation frequency due to the capacitive nature of the devices, which is well captured by numerical simulations of an equivalent electrical circuit. These results provide new insights into the electroluminescence dynamics of AC‐driven perovskite light‐emitting transistors and demonstrate an effective strategy to optimize device performance through independent control of the litude, frequency, and phase of the biasing pulses.
Publisher: Wiley
Date: 14-02-2022
Abstract: The Rashba effect, i.e., the splitting of electronic spin‐polarized bands in the momentum space of a crystal with broken inversion symmetry, has enabled the realization of spin‐orbitronic devices, in which spins are manipulated by spin–orbit coupling. In optics, where the helicity of light polarization represents the spin degree of freedom for spin–momentum coupling, the optical Rashba effect is manifested by the splitting of optical states with opposite chirality in the momentum space. Previous realizations of the optical Rashba effect relied on passive devices determining the surface plasmon or light propagation inside nanostructures, or the directional emission of chiral luminescence when hybridized with light‐emitting media. An active device underpinned by the optical Rashba effect is demonstrated here, in which a monolithic halide perovskite metasurface emits highly directional chiral photoluminescence. An all‐dielectric metasurface design with broken in‐plane inversion symmetry is directly embossed into the high‐refractive‐index, light‐emitting perovskite film, yielding a degree of circular polarization of photoluminescence of 60% at room temperature.
Publisher: OSA
Date: 2014
Publisher: Wiley
Date: 23-11-2022
Abstract: Emerging immersive visual communication technologies require light sources with complex functionality for dynamic control of polarization, directivity, wavefront, spectrum, and intensity of light. Currently, this is mostly achieved by free space bulk optic elements, limiting the adoption of these technologies. Flat optics based on artificially structured metasurfaces that operate at the sub‐wavelength scale are a viable solution, however, their integration into electrically driven devices remains challenging. Here, a radically new approach to monolithic integration of a dielectric metasurface into a perovskite light‐emitting transistor is demonstrated. It is shown that nanogratings directly structured on top of the transistor channel yield an 8‐fold increase of electroluminescence intensity and dynamic tunability of polarization. This new light‐emitting metatransistor device concept opens unlimited opportunities for light management strategies based on metasurface design and integration.
Publisher: American Chemical Society (ACS)
Date: 15-11-2019
Publisher: American Chemical Society (ACS)
Date: 04-2015
DOI: 10.1021/ACS.JPCLETT.5B00431
Abstract: Solar cells based on organic-inorganic lead iodide perovskite (CH3NH3PbI3) exhibit remarkably high power conversion efficiency (PCE). One of the key issues in solution-processed films is that often the polycrystalline domain orientation is not well-defined, which makes it difficult to predict energy alignment and charge transfer efficiency. Here we combine ab initio calculations and photoelectron spectroscopy to unravel the electronic structure and charge redistribution at the interface between different surfaces of CH3NH3PbI3 and typical organic hole acceptor Spiro-OMeTAD and electron acceptor PCBM. We find that both hole and electron interfacial transfer depend strongly on the CH3NH3PbI3 surface orientation: while the (001) and (110) surfaces tend to favor hole injection to Spiro-OMeTAD, the (100) surface facilitates electron transfer to PCBM due to surface delocalized charges and hole/electron accumulation at the CH3NH3PbI3/organic interfaces. Molecular dynamic simulations indicate that this is due to strong orbital interactions under thermal fluctuations at room temperature, suggesting the possibility to further improve charge separation and extraction in perovskite-based solar cells by controlling perovskite film crystallization and surface orientation.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2022
DOI: 10.1038/S41467-022-29253-0
Abstract: Recent attempts to synthesize hybrid perovskites with large chirality have been h ered by large size mismatch and weak interaction between their structure and the wavelength of light. Here we adopt a planar nanostructure design to overcome these limitations and realize all-dielectric perovskite metasurfaces with giant superstructural chirality. We identify a direct spectral correspondence between the near- and the far- field chirality, and tune the electric and magnetic multipole moments of the resonant chiral metamolecules to obtain large anisotropy factor of 0.49 and circular dichroism of 6350 mdeg. Simulations show that larger area metasurfaces could yield even higher optical activity, approaching the theoretical limits. Our results clearly demonstrate the advantages of nanostructrure engineering for the implementation of perovskite chiral photonic, optoelectronic, and spintronic devices.
Publisher: IEEE
Date: 21-06-2021
No related grants have been discovered for Cesare Soci.