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Yantara N, Bruno A, Iqbal A, Jamaludin NF, Soci C, Mhaisalkar S, Mathews N. Designing Efficient Energy Funneling Kinetics in Ruddlesden-Popper Perovskites for High-Performance Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800818. [PMID: 29971842 DOI: 10.1002/adma.201800818] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/17/2018] [Indexed: 05/11/2023]
Abstract
Mixed Ruddlesden-Popper (RP) perovskites are of great interest in light-emitting diodes (LEDs), due to the efficient energy transfer (funneling) from high-bandgap (donor) domains to low-bandgap (acceptor) domains, which leads to enhanced photoluminescence (PL) intensity, long PL lifetime, and high-efficiency LEDs. However, the influence of reduced effective emitter centers in the active emissive film, as well as the implications of electrical injection into the larger bandgap donor material, have not been addressed in the context of an active device. The electrical and optical signatures of the energy cascading mechanisms are critically assessed and modulated in a model RP perovskite series ((C8 H17 NH3 )2 (CH(NH2 )2 )m-1 Pbm Br3m+1 ). Optimized devices demonstrate a current efficiency of 22.9 cd A-1 and 5% external quantum efficiency, more than five times higher than systems where funneling is absent. The signature of nonideal funneling in RP perovskites is revealed by the appearance of donor electroluminescence from the device, followed by a reduction in the LED performance.
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Bargigia I, Zucchetti E, Kandada ARS, Moreira M, Bossio C, Wong WPD, Miranda PB, Decuzzi P, Soci C, D'Andrea C, Lanzani G. The Photophysics of Polythiophene Nanoparticles for Biological Applications. Chembiochem 2018; 20:532-536. [DOI: 10.1002/cbic.201800167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Indexed: 11/12/2022]
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Alonzo M, Moscatelli D, Bastiani L, Belardini A, Soci C, Fazio E. All-Optical Reinforcement Learning In Solitonic X-Junctions. Sci Rep 2018; 8:5716. [PMID: 29632391 PMCID: PMC5890259 DOI: 10.1038/s41598-018-24084-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/27/2018] [Indexed: 11/26/2022] Open
Abstract
Ethology has shown that animal groups or colonies can perform complex calculation distributing simple decision-making processes to the group members. For example ant colonies can optimize the trajectories towards the food by performing both a reinforcement (or a cancellation) of the pheromone traces and a switch from one path to another with stronger pheromone. Such ant’s processes can be implemented in a photonic hardware to reproduce stigmergic signal processing. We present innovative, completely integrated X-junctions realized using solitonic waveguides which can provide both ant’s decision-making processes. The proposed X-junctions can switch from symmetric (50/50) to asymmetric behaviors (80/20) using optical feedbacks, vanishing unused output channels or reinforcing the used ones.
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Jamaludin NF, Yantara N, Ng YF, Li M, Goh TW, Thirumal K, Sum TC, Mathews N, Soci C, Mhaisalkar S. Grain Size Modulation and Interfacial Engineering of CH3
NH3
PbBr3
Emitter Films through Incorporation of Tetraethylammonium Bromide. Chemphyschem 2018; 19:1075-1080. [DOI: 10.1002/cphc.201701380] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Indexed: 11/09/2022]
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Vázquez MR, Bharadwaj V, Sotillo B, Lo SZA, Ramponi R, Zheludev NI, Lanzani G, Eaton SM, Soci C. Optical NP problem solver on laser-written waveguide platform. OPTICS EXPRESS 2018; 26:702-710. [PMID: 29401952 DOI: 10.1364/oe.26.000702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/26/2017] [Indexed: 06/07/2023]
Abstract
Cognitive photonic networks are researched to efficiently solve computationally hard problems. Flexible fabrication techniques for the implementation of such networks into compact and scalable chips are desirable for the study of new optical computing schemes and algorithm optimization. Here we demonstrate a femtosecond laser-written optical oracle based on cascaded directional couplers in glass, for the solution of the Hamiltonian path problem. By interrogating the integrated photonic chip with ultrashort laser pulses, we were able to distinguish the different paths traveled by light pulses, and thus infer the existence or the absence of the Hamiltonian path in the network by using an optical correlator. This work proves that graph theory problems may be easily implemented in integrated photonic networks, down scaling the net size and speeding up execution times.
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Neogi I, Bruno A, Bahulayan D, Goh TW, Ghosh B, Ganguly R, Cortecchia D, Sum TC, Soci C, Mathews N, Mhaisalkar SG. Broadband-Emitting 2 D Hybrid Organic-Inorganic Perovskite Based on Cyclohexane-bis(methylamonium) Cation. CHEMSUSCHEM 2017; 10:3765-3772. [PMID: 28752545 DOI: 10.1002/cssc.201701227] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Indexed: 05/06/2023]
Abstract
A new broadband-emitting 2 D hybrid organic-inorganic perovskite (CyBMA)PbBr4 based on highly flexible cis-1,3-bis(methylaminohydrobromide)cyclohexane (CyBMABr) core has been designed, synthesized, and investigated, highlighting the effects of stereoisomerism of the templating cation on the formation and properties of the resulting perovskite. The new 2 D material has high exciton binding energy of 340 meV and a broad emission spanning from 380 to 750 nm, incorporating a prominent excitonic band and a less intense broad peak at room temperature. Significant changes in the photoluminescence (PL) spectrum were observed at lower temperatures, showing remarkable enhancement in the intensity of the broadband at the cost of excitonic emission. Temperature-dependent PL mapping indicates the effective role of only a narrow band of excitonic absorption in the generation of the active channel for emission. Based on the evidences obtained from the photophysical investigations, we attributed the evolution of the broad B-band of (CyBMA)PbBr4 to excitonic self-trapped states.
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Glaeske M, Kumar M, Bisswanger T, Vaitiekenas S, Soci C, Narula R, Bruno A, Setaro A. Relaxation lifetimes of plasmonically enhanced hybrid gold-carbon nanotubes systems. NANOTECHNOLOGY 2017; 28:255202. [PMID: 28520555 DOI: 10.1088/1361-6528/aa7409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recently, we introduced a novel hybridization route for carbon nanotubes using gold nanoparticles, whose close proximity neatly enhances their radiative emission. Here we investigate the mechanisms behind the enhancement by monitoring the de-excitation dynamics of our π-hybrids through two-color pump-probe time-resolved spectroscopy. The de-excitation process reveals a fast component and a slow component. We find that the presence of gold prominently affects the fast processes, indicating a stronger influence of the gold nanoparticle on the intra-band non-radiative relaxation than on the inter-band recombination of the single-walled carbon nanotube. By evaluating the de-excitation times, we estimate the balance between near-field pumping and the faster metal-induced de-excitation contributions, proving the enhanced pumping to be the leading mechanism.
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Liu R, Chen R, Elthakeb AT, Lee SH, Hinckley S, Khraiche ML, Scott J, Pre D, Hwang Y, Tanaka A, Ro YG, Matsushita AK, Dai X, Soci C, Biesmans S, James A, Nogan J, Jungjohann KL, Pete DV, Webb DB, Zou Y, Bang AG, Dayeh SA. High Density Individually Addressable Nanowire Arrays Record Intracellular Activity from Primary Rodent and Human Stem Cell Derived Neurons. NANO LETTERS 2017; 17:2757-2764. [PMID: 28384403 PMCID: PMC6045931 DOI: 10.1021/acs.nanolett.6b04752] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We report a new hybrid integration scheme that offers for the first time a nanowire-on-lead approach, which enables independent electrical addressability, is scalable, and has superior spatial resolution in vertical nanowire arrays. The fabrication of these nanowire arrays is demonstrated to be scalable down to submicrometer site-to-site spacing and can be combined with standard integrated circuit fabrication technologies. We utilize these arrays to perform electrophysiological recordings from mouse and rat primary neurons and human induced pluripotent stem cell (hiPSC)-derived neurons, which revealed high signal-to-noise ratios and sensitivity to subthreshold postsynaptic potentials (PSPs). We measured electrical activity from rodent neurons from 8 days in vitro (DIV) to 14 DIV and from hiPSC-derived neurons at 6 weeks in vitro post culture with signal amplitudes up to 99 mV. Overall, our platform paves the way for longitudinal electrophysiological experiments on synaptic activity in human iPSC based disease models of neuronal networks, critical for understanding the mechanisms of neurological diseases and for developing drugs to treat them.
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Gholipour B, Adamo G, Cortecchia D, Krishnamoorthy HNS, Birowosuto MD, Zheludev NI, Soci C. Organometallic Perovskite Metasurfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1604268. [PMID: 28054390 DOI: 10.1002/adma.201604268] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/07/2016] [Indexed: 06/06/2023]
Abstract
Organometallic perovskites, solution-processable materials with outstanding optoelectronic properties and high index of refraction, provide a platform for all-dielectric metamaterials operating at visible frequencies. Perovskite metasurfaces with structural coloring tunable across visible frequencies are realized through subwavelength structuring. Moreover, a threefold increase of the luminescence yield and comparable reduction of luminescence decay time are observed.
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Ng YF, Kulkarni SA, Parida S, Jamaludin NF, Yantara N, Bruno A, Soci C, Mhaisalkar S, Mathews N. Highly efficient Cs-based perovskite light-emitting diodes enabled by energy funnelling. Chem Commun (Camb) 2017; 53:12004-12007. [DOI: 10.1039/c7cc06615e] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Incorporation of phenylethylammonium bromide into a fully inorganic CsPbBr3 perovskite framework led to the formation of quasi-2D perovskites with exceptional energy funnelling via an energy cascade.
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Cortecchia D, Neutzner S, Srimath Kandada AR, Mosconi E, Meggiolaro D, De Angelis F, Soci C, Petrozza A. Broadband Emission in Two-Dimensional Hybrid Perovskites: The Role of Structural Deformation. J Am Chem Soc 2016; 139:39-42. [DOI: 10.1021/jacs.6b10390] [Citation(s) in RCA: 264] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Cortecchia D, Soci C, Cametti M, Petrozza A, Martí-Rujas J. Crystal Engineering of a Two-Dimensional Lead-Free Perovskite with Functional Organic Cations by Second-Sphere Coordination. Chempluschem 2016; 82:671. [DOI: 10.1002/cplu.201600603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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Cortecchia D, Soci C, Cametti M, Petrozza A, Martí-Rujas J. Cover Picture: Crystal Engineering of a Two-Dimensional Lead-Free Perovskite with Functional Organic Cations by Second-Sphere Coordination (ChemPlusChem 5/2017). Chempluschem 2016. [DOI: 10.1002/cplu.201600604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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39
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Lova P, Bastianini C, Giusto P, Patrini M, Rizzo P, Guerra G, Iodice M, Soci C, Comoretto D. Label-Free Vapor Selectivity in Poly(p-Phenylene Oxide) Photonic Crystal Sensors. ACS APPLIED MATERIALS & INTERFACES 2016; 8:31941-31950. [PMID: 27808494 DOI: 10.1021/acsami.6b10809] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The lack of sensors for low cost, extensive, and continuous detection of vapor pollutants is a serious concern for health and safety in industrialized urban areas. Colorimetric sensors, such as distributed Bragg reflectors made of polymers, could achieve this task thanks to their low cost and easy signal transduction but are typically affected by low vapor permeability and lack of selectivity without chemical labeling. Here we demonstrate all-polymer Bragg multilayers for label-free selective detection of organic volatile compounds. The system exploits the ability of amorphous poly(p-phenylene oxide), PPO, to uptake large amount of guest molecules and to form cocrystalline phases with distinct optical properties. Bragg stacks embedding PPO active layers show selective colorimetric response to vapors of carbon tetrachloride and aromatic homologues, which can be revealed by the naked eye.
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Cortecchia D, Soci C, Cametti M, Petrozza A, Martí-Rujas J. Crystal Engineering of a Two-Dimensional Lead-Free Perovskite with Functional Organic Cations by Second-Sphere Coordination. Chempluschem 2016; 82:681-685. [DOI: 10.1002/cplu.201600477] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Indexed: 11/11/2022]
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41
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Gholipour B, Bastock P, Cui L, Craig C, Khan K, Hewak DW, Soci C. Lithography Assisted Fiber-Drawing Nanomanufacturing. Sci Rep 2016; 6:35409. [PMID: 27739543 PMCID: PMC5064402 DOI: 10.1038/srep35409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 09/27/2016] [Indexed: 01/10/2023] Open
Abstract
We present a high-throughput and scalable technique for the production of metal nanowires embedded in glass fibres by taking advantage of thin film properties and patterning techniques commonly used in planar microfabrication. This hybrid process enables the fabrication of single nanowires and nanowire arrays encased in a preform material within a single fibre draw, providing an alternative to costly and time-consuming iterative fibre drawing. This method allows the combination of materials with different thermal properties to create functional optoelectronic nanostructures. As a proof of principle of the potential of this technique, centimetre long gold nanowires (bulk Tm = 1064 °C) embedded in silicate glass fibres (Tg = 567 °C) were drawn in a single step with high aspect ratios (>104); such nanowires can be released from the glass matrix and show relatively high electrical conductivity. Overall, this fabrication method could enable mass manufacturing of metallic nanowires for plasmonics and nonlinear optics applications, as well as the integration of functional multimaterial structures for completely fiberised optoelectronic devices.
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Yuan GH, Vezzoli S, Altuzarra C, Rogers ETF, Couteau C, Soci C, Zheludev NI. Quantum super-oscillation of a single photon. LIGHT, SCIENCE & APPLICATIONS 2016; 5:e16127. [PMID: 30167180 PMCID: PMC6059939 DOI: 10.1038/lsa.2016.127] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 05/14/2023]
Abstract
Super-oscillation is a counterintuitive phenomenon describing localized fast variations of functions and fields that happen at frequencies higher than the highest Fourier component of their spectra. The physical implications of this effect have been studied in information theory and optics of classical fields, and have been used in super-resolution imaging. As a general phenomenon of wave dynamics, super-oscillations have also been predicted to exist in quantum wavefunctions. Here we report the experimental demonstration of super-oscillatory behavior of a single-quantum object, a photon. The super-oscillatory behavior is demonstrated by tight localization of the photon wavefunction after focusing with an appropriately designed slit mask to create an interference pattern with a sub-diffraction hotspot (~0.45 λ). Such quantum super-oscillation can be used for low-intensity far-field super-resolution imaging techniques even down to single-photon counting regime, which would be of interest to quantum physics and non-invasive and label-free biological studies.
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Ma L, Hu P, Jiang H, Kloc C, Sun H, Soci C, Voityuk AA, Michel-Beyerle ME, Gurzadyan GG. Single photon triggered dianion formation in TCNQ and F4TCNQ crystals. Sci Rep 2016; 6:28510. [PMID: 27346797 PMCID: PMC4921923 DOI: 10.1038/srep28510] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 06/06/2016] [Indexed: 12/15/2022] Open
Abstract
Excited state dynamics in two strong organic electron acceptor systems, TCNQ and F4TCNQ single crystals, was studied. After absorption of a single photon, dianions are formed in both crystals on ultrashort timescale: TCNQ τ < 50 fs, F4TCNQ τ = 4 ps. By use of transient absorption spectroscopy, we demonstrate that the dianion formation in F4TCNQ is mediated by the radical anion precursor which is described by a two-step model. Our measurements show the phenomenon that in this quinoid acceptor crystals in the absence of additional donor molecule, it is possible to resolve the two step formation of a doubly charged anion upon absorption of a single low energy photon (2.6 eV).
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Hu W, Wu K, Shum PP, Zheludev NI, Soci C. All-Optical Implementation of the Ant Colony Optimization Algorithm. Sci Rep 2016; 6:26283. [PMID: 27222098 PMCID: PMC4879568 DOI: 10.1038/srep26283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/22/2016] [Indexed: 11/09/2022] Open
Abstract
We report all-optical implementation of the optimization algorithm for the famous "ant colony" problem. Ant colonies progressively optimize pathway to food discovered by one of the ants through identifying the discovered route with volatile chemicals (pheromones) secreted on the way back from the food deposit. Mathematically this is an important example of graph optimization problem with dynamically changing parameters. Using an optical network with nonlinear waveguides to represent the graph and a feedback loop, we experimentally show that photons traveling through the network behave like ants that dynamically modify the environment to find the shortest pathway to any chosen point in the graph. This proof-of-principle demonstration illustrates how transient nonlinearity in the optical system can be exploited to tackle complex optimization problems directly, on the hardware level, which may be used for self-routing of optical signals in transparent communication networks and energy flow in photonic systems.
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Nguyen DM, Soci C, Ooi CHR. Coherently Tunable Triangular Trefoil Phaseonium Metamaterial. Sci Rep 2016; 6:21083. [PMID: 26879520 PMCID: PMC4754698 DOI: 10.1038/srep21083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/11/2016] [Indexed: 12/04/2022] Open
Abstract
Phaseonium is a three-level Λ quantum system, in which a coherent microwave and an optical control (pump) beams can be used to actively modulate the dielectric response. Here we propose a new metamaterial structure comprising of a periodic array of triangular phaseonium metamolecules arranged as a trefoil. We present a computational study of the spatial distribution of magnetic and electric fields of the probe light and the corresponding transmission and reflection, for various parameters of the optical and microwave beams. For specific values of the probing frequencies and control fields, the phaseonium can display either metallic or dielectric optical response. We find that, in the metallic regime, the phaseonium metamaterial structure supports extremely large transmission, with optical amplification at large enough intensity of the microwave thanks to strong surface plasmon coupling; while, in the dielectric regime without microwave excitation, the transmission bandwidth can be tuned by varying the control beam intensity. Implementation of such phaseonium metamaterial structure in solid-state systems, such as patterned crystals doped with rare-earth elements or dielectric matrices embedded with quantum dots, could enable a new class of actively tunable quantum metamaterials.
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Cortecchia D, Dewi HA, Yin J, Bruno A, Chen S, Baikie T, Boix PP, Grätzel M, Mhaisalkar S, Soci C, Mathews N. Lead-Free MA2CuCl(x)Br(4-x) Hybrid Perovskites. Inorg Chem 2016; 55:1044-52. [PMID: 26756860 DOI: 10.1021/acs.inorgchem.5b01896] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
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, and bioaccumulative Pb, which may eventually hamper their commercialization. Here, we present the synthesis of two-dimensional (2D) Cu-based hybrid perovskites and study their optoelectronic properties to investigate their potential application in solar cells and light-emitting devices, providing a new environmental-friendly alternative to Pb. The series (CH3NH3)2CuCl(x)Br(4-x) was studied in detail, with the role of Cl found to be essential for stabilization. By exploiting the additional Cu d-d transitions and appropriately tuning the Br/Cl ratio, which affects ligand-to-metal charge transfer transitions, the optical absorption in this series of compounds can be extended to the near-infrared for optimal spectral overlap with the solar irradiance. In situ formation of Cu(+) ions was found to be responsible for the green photoluminescence of this material set. Processing conditions for integrating Cu-based perovskites into photovoltaic device architectures, as well as the factors currently limiting photovoltaic performance, are discussed: among them, we identified the combination of low absorption coefficient and heavy mass of the holes as main limitations for the solar cell efficiency. To the best of our knowledge, this is the first demonstration of the potential of 2D copper perovskite as light harvesters and lays the foundation for further development of perovskite based on transition metals as alternative lead-free materials. Appropriate molecular design will be necessary to improve the material's properties and solar cell performance filling the gap with the state-of-the-art Pb-based perovskite devices.
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Kumar M, Vezzoli S, Wang Z, Chaudhary V, Ramanujan RV, Gurzadyan GG, Bruno A, Soci C. Hot exciton cooling and multiple exciton generation in PbSe quantum dots. Phys Chem Chem Phys 2016; 18:31107-31114. [DOI: 10.1039/c6cp03790a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PbSe QDs show high multiple exciton generation (MEG) quantum yield. Here we have investigated the role of theΣtransition in slowing down the hot exciton cooling, which can help MEG to take over phonon relaxation.
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Raavi SSK, Yin J, Grancini G, Soci C, Rao SV, Lanzani G, Giribabu L. Femtosecond to Microsecond Dynamics of Soret-Band Excited Corroles. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2015; 119:28691-28700. [PMID: 26631153 DOI: 10.1021/acs.jpcc.5b08235] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a comprehensive photophysical investigation on a series of three corroles (TTC, P-TTC, Ge-TTC dissolved in toluene), employing femtosecond and nanosecond transient absorption spectroscopy (TAS) measurements. Systematic analyses of the TAS data determined the rates and corresponding time constants of photophysical processes: internal conversion (τIC) in the 898-525 fs range, vibrational relaxation (τ_VR) in the 7.44-13.6 ps range, intersystem crossing (τISC ) in the 033-1.09 ns range and triplet lifetime (τ_triplet) in the 0.8-3.5μs range. The estimated triplet quantum yields (ΦTriplet) were in the 0.42 - 0.61 range. Comparatively, GeTTC displayed faster τIC and higher(ΦTriplet). Additionally, the time-dependent density functional theory (DFT) calculations were performed for the three molecules. The HOMO/LUMO energy levels and the oscillator strengths of various transitions were determined and presented.
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Raavi SSK, Yin J, Grancini G, Soci C, Rao SV, Lanzani G, Giribabu L. Femtosecond to Microsecond Dynamics of Soret-Band Excited Corroles. J Phys Chem A 2015. [DOI: 10.1021/acs.jpca.5b08235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Krishna A, Sabba D, Yin J, Bruno A, Boix PP, Gao Y, Dewi HA, Gurzadyan GG, Soci C, Mhaisalkar SG, Grimsdale AC. Facile Synthesis of a Furan-Arylamine Hole-Transporting Material for High-Efficiency, Mesoscopic Perovskite Solar Cells. Chemistry 2015; 21:15113-7. [DOI: 10.1002/chem.201503099] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 11/08/2022]
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