ORCID Profile
0000-0003-0396-6495
Current Organisation
University of Toronto
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Catalysis and mechanisms of reactions | Electrochemistry | Functional materials | Physical chemistry | Electrochemical energy storage and conversion
Publisher: Springer Science and Business Media LLC
Date: 07-12-2020
Publisher: Springer Science and Business Media LLC
Date: 11-11-2019
Publisher: Springer Science and Business Media LLC
Date: 25-04-2023
DOI: 10.1038/S41467-023-37898-8
Abstract: Performing CO 2 reduction in acidic conditions enables high single-pass CO 2 conversion efficiency. However, a faster kinetics of the hydrogen evolution reaction compared to CO 2 reduction limits the selectivity toward multicarbon products. Prior studies have shown that adsorbed hydroxide on the Cu surface promotes CO 2 reduction in neutral and alkaline conditions. We posited that limited adsorbed hydroxide species in acidic CO 2 reduction could contribute to a low selectivity to multicarbon products. Here we report an electrodeposited Cu catalyst that suppresses hydrogen formation and promotes selective CO 2 reduction in acidic conditions. Using in situ time-resolved Raman spectroscopy, we show that a high concentration of CO and OH on the catalyst surface promotes C-C coupling, a finding that we correlate with evidence of increased CO residence time. The optimized electrodeposited Cu catalyst achieves a 60% faradaic efficiency for ethylene and 90% for multicarbon products. When deployed in a slim flow cell, the catalyst attains a 20% energy efficiency to ethylene, and 30% to multicarbon products.
Publisher: Springer Science and Business Media LLC
Date: 16-12-2019
Publisher: American Chemical Society (ACS)
Date: 25-05-2018
Publisher: Elsevier BV
Date: 06-2023
Publisher: Springer Science and Business Media LLC
Date: 11-02-2019
Publisher: Springer Science and Business Media LLC
Date: 21-01-2019
Publisher: Springer Science and Business Media LLC
Date: 23-07-2020
DOI: 10.1038/S41467-020-17499-5
Abstract: Multi-carbon alcohols such as ethanol are valued as fuels in view of their high energy density and ready transport. Unfortunately, the selectivity toward alcohols in CO 2 /CO electroreduction is diminished by ethylene production, especially when operating at high current densities ( mA cm −2 ). Here we report a metal doping approach to tune the adsorption of hydrogen at the copper surface and thereby promote alcohol production. Using density functional theory calculations, we screen a suite of transition metal dopants and find that incorporating Pd in Cu moderates hydrogen adsorption and assists the hydrogenation of C 2 intermediates, providing a means to favour alcohol production and suppress ethylene. We synthesize a Pd-doped Cu catalyst that achieves a Faradaic efficiency of 40% toward alcohols and a partial current density of 277 mA cm −2 from CO electroreduction. The activity exceeds that of prior reports by a factor of 2.
Publisher: Springer Science and Business Media LLC
Date: 29-11-2019
DOI: 10.1038/S41467-019-13190-6
Abstract: The electroreduction of C 1 feedgas to high-energy-density fuels provides an attractive avenue to the storage of renewable electricity. Much progress has been made to improve selectivity to C 1 and C 2 products, however, the selectivity to desirable high-energy-density C 3 products remains relatively low. We reason that C 3 electrosynthesis relies on a higher-order reaction pathway that requires the formation of multiple carbon-carbon (C-C) bonds, and thus pursue a strategy explicitly designed to couple C 2 with C 1 intermediates. We develop an approach wherein neighboring copper atoms having distinct electronic structures interact with two adsorbates to catalyze an asymmetric reaction. We achieve a record n -propanol Faradaic efficiency (FE) of (33 ± 1)% with a conversion rate of (4.5 ± 0.1) mA cm −2 , and a record n -propanol cathodic energy conversion efficiency (EE cathodic half-cell ) of 21%. The FE and EE cathodic half-cell represent a 1.3× improvement relative to previously-published CO-to- n -propanol electroreduction reports.
Publisher: Springer Science and Business Media LLC
Date: 13-03-2023
Publisher: American Chemical Society (ACS)
Date: 21-08-2018
Abstract: In tandem catalysis, two distinct catalytic materials are interfaced to feed the product of one reaction into the next one. This approach, analogous to enzyme cascades, can potentially be used to upgrade small molecules such as CO
Publisher: Springer Science and Business Media LLC
Date: 05-11-2018
DOI: 10.1038/S41467-018-07032-0
Abstract: The electrochemical reduction of carbon monoxide is a promising approach for the renewable production of carbon-based fuels and chemicals. Copper shows activity toward multi-carbon products from CO reduction, with reaction selectivity favoring two-carbon products however, efficient conversion of CO to higher carbon products such as n-propanol, a liquid fuel, has yet to be achieved. We hypothesize that copper adparticles, possessing a high density of under-coordinated atoms, could serve as preferential sites for n-propanol formation. Density functional theory calculations suggest that copper adparticles increase CO binding energy and stabilize two-carbon intermediates, facilitating coupling between adsorbed *CO and two-carbon intermediates to form three-carbon products. We form adparticle-covered catalysts in-situ by mediating catalyst growth with strong CO chemisorption. The new catalysts exhibit an n-propanol Faradaic efficiency of 23% from CO reduction at an n-propanol partial current density of 11 mA cm −2 .
Publisher: Wiley
Date: 16-11-2022
Abstract: High‐rate conversion of carbon dioxide (CO 2 ) to ethylene (C 2 H 4 ) in the CO 2 reduction reaction (CO 2 RR) requires fine control over the phase boundary of the gas diffusion electrode (GDE) to overcome the limit of CO 2 solubility in aqueous electrolytes. Here, a metal–organic framework (MOF)‐functionalized GDE design is presented, based on a catalysts:MOFs:hydrophobic substrate materials layered architecture, that leads to high‐rate and selective C 2 H 4 production in flow cells and membrane electrode assembly (MEA) electrolyzers. It is found that using electroanalysis and operando X‐ray absorption spectroscopy (XAS), MOF‐induced organic layers in GDEs augment the local CO 2 concentration near the active sites of the Cu catalysts. MOFs with different CO 2 adsorption abilities are used, and the stacking ordering of MOFs in the GDE is varied. While sputtering Cu on poly(tetrafluoroethylene) (PTFE) (Cu/PTFE) exhibits 43% C 2 H 4 Faradaic efficiency (FE) at a current density of 200 mA cm − 2 in a flow cell, 49% C 2 H 4 FE at 1 A cm − 2 is achieved on MOF‐augmented GDEs in CO 2 RR. MOF‐augmented GDEs are further evaluated in an MEA electrolyzer, achieving a C 2 H 4 partial current density of 220 mA cm −2 for CO 2 RR and 121 mA cm −2 for the carbon monoxide reduction reaction (CORR), representing 2.7‐fold and 15‐fold improvement in C 2 H 4 production rate, compared to those obtained on bare Cu/PTFE.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 16-08-2019
Abstract: The perovskite materials used for solar cells and light-emitting diodes (which are black in color) are generally less stable at room temperature than the electronically inactive nonperovskite phases (which are yellow in color). Steele et al. show that for CsPbI 3 , strain induced in a thin film after annealing the material to 330°C and then rapidly cooling it to room temperature kinetically trapped the black phase. Grazing-incidence wide-angle x-ray scattering revealed the crystal distortions and texture formation created by interfacial strain. Science , this issue p. 679
Publisher: American Chemical Society (ACS)
Date: 02-03-2020
DOI: 10.1021/JACS.9B13347
Publisher: Springer Science and Business Media LLC
Date: 10-02-2022
DOI: 10.1038/S41467-022-28456-9
Abstract: Nitrogen-doped graphene-supported single atoms convert CO 2 to CO, but fail to provide further hydrogenation to methane – a finding attributable to the weak adsorption of CO intermediates. To regulate the adsorption energy, here we investigate the metal-supported single atoms to enable CO 2 hydrogenation. We find a copper-supported iron-single-atom catalyst producing a high-rate methane. Density functional theory calculations and in-situ Raman spectroscopy show that the iron atoms attract surrounding intermediates and carry out hydrogenation to generate methane. The catalyst is realized by assembling iron phthalocyanine on the copper surface, followed by in-situ formation of single iron atoms during electrocatalysis, identified using operando X-ray absorption spectroscopy. The copper-supported iron-single-atom catalyst exhibits a CO 2 -to-methane Faradaic efficiency of 64% and a partial current density of 128 mA cm −2 , while the nitrogen-doped graphene-supported one produces only CO. The activity is 32 times higher than a pristine copper under the same conditions of electrolyte and bias.
Publisher: Springer Science and Business Media LLC
Date: 02-06-2022
DOI: 10.1038/S41467-022-30677-X
Abstract: Electrochemical reduction of CO 2 to multi-carbon products (C 2+ ), when powered using renewable electricity, offers a route to valuable chemicals and fuels. In conventional neutral-media CO 2 -to-C 2+ devices, as much as 70% of input CO 2 crosses the cell and mixes with oxygen produced at the anode. Recovering CO 2 from this stream adds a significant energy penalty. Here we demonstrate that using a liquid-to-liquid anodic process enables the recovery of crossed-over CO 2 via facile gas-liquid separation without additional energy input: the anode tail gas is directly fed into the cathodic input, along with fresh CO 2 feedstock. We report a system exhibiting a low full-cell voltage of 1.9 V and total carbon efficiency of 48%, enabling 262 GJ/ton ethylene, a 46% reduction in energy intensity compared to state-of-art single-stage CO 2 -to-C 2+ devices. The strategy is compatible with today’s highest-efficiency electrolyzers and CO 2 catalysts that function optimally in neutral and alkaline electrolytes.
Publisher: Springer Science and Business Media LLC
Date: 06-12-2022
DOI: 10.1038/S41467-022-35255-9
Abstract: The black perovskite phase of CsPbI 3 is promising for optoelectronic applications however, it is unstable under ambient conditions, transforming within minutes into an optically inactive yellow phase, a fact that has so far prevented its widespread adoption. Here we use coarse photolithography to embed a PbI 2 -based interfacial microstructure into otherwise-unstable CsPbI 3 perovskite thin films and devices. Films fitted with a tessellating microgrid are rendered resistant to moisture-triggered decay and exhibit enhanced long-term stability of the black phase (beyond 2.5 years in a dry environment), due to increasing the phase transition energy barrier and limiting the spread of potential yellow phase formation to structurally isolated domains of the grid. This stabilizing effect is readily achieved at the device level, where unencapsulated CsPbI 3 perovskite photodetectors display ambient-stable operation. These findings provide insights into the nature of phase destabilization in emerging CsPbI 3 perovskite devices and demonstrate an effective stabilization procedure which is entirely orthogonal to existing approaches.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-06-2020
Abstract: Ethylene oxide is a strained, reactive molecule produced on a vast scale as a plastics precursor. The current method of synthesis involves the direct reaction of ethylene and oxygen at high temperature, but the original protocol relied on the reduction of chlorine to produce a chlorohydrin intermediate. Leow et al. report a room temperature method that returns to the chlorine route but uses electrochemistry to generate it catalytically from chloride (see the Perspective by Barton). This efficient process uses water in place of oxygen and can be integrated with the electrochemical generation of ethylene from carbon dioxide. Propylene oxide can be produced using the same method. Science , this issue p. 1228 see also p. 1181
Publisher: Springer Science and Business Media LLC
Date: 06-01-2020
Publisher: American Chemical Society (ACS)
Date: 11-09-2023
Publisher: Springer Science and Business Media LLC
Date: 13-08-2018
Publisher: Springer Science and Business Media LLC
Date: 07-06-2023
DOI: 10.1038/S41467-023-38935-2
Abstract: Renewable CH 4 produced from electrocatalytic CO 2 reduction is viewed as a sustainable and versatile energy carrier, compatible with existing infrastructure. However, conventional alkaline and neutral CO 2 -to-CH 4 systems suffer CO 2 loss to carbonates, and recovering the lost CO 2 requires input energy exceeding the heating value of the produced CH 4 . Here we pursue CH 4 -selective electrocatalysis in acidic conditions via a coordination method, stabilizing free Cu ions by bonding Cu with multidentate donor sites. We find that hexadentate donor sites in ethylenediaminetetraacetic acid enable the chelation of Cu ions, regulating Cu cluster size and forming Cu-N/O single sites that achieve high CH 4 selectivity in acidic conditions. We report a CH 4 Faradaic efficiency of 71% (at 100 mA cm −2 ) with % loss in total input CO 2 that results in an overall energy intensity (254 GJ/tonne CH 4 ), half that of existing electroproduction routes.
Publisher: Springer Science and Business Media LLC
Date: 20-02-2020
DOI: 10.1038/S41467-020-14883-Z
Abstract: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Publisher: Springer Science and Business Media LLC
Date: 11-01-2021
Publisher: American Chemical Society (ACS)
Date: 25-10-2018
DOI: 10.1021/ACS.NANOLETT.8B03020
Abstract: Quantum dots (QDs) are promising candidates for solution-processed thin-film optoelectronic devices. Both the diffusion length and the mobility of photoexcited charge carriers in QD solids are critical determinants of solar cell performance yet various techniques offer erse values of these key parameters even in notionally similar films. Here we report diffusion lengths and interdot charge transfer rates using a 3D donor/acceptor technique that directly monitors the rate at which photoexcitations reach small-bandgap dot inclusions having a known spacing within a larger-bandgap QD matrix. Instead of relying on photoluminescence (which can be weak in strongly coupled QD solids), we use ultrafast transient absorption spectroscopy, a method where sensitivity is undiminished by exciton dissociation. We measure record diffusion lengths of ∼300 nm in metal halide exchanged PbS QD solids that have led to power conversion efficiencies of 12%, and determine 8 ps interdot hopping of carriers following photoexcitation, among the fastest rates reported for PbS QD solids. We also find that QD solids composed of smaller QDs ( d = ∼3.2 nm) exhibit 5 times faster interdot charge transfer rates and 10 times lower trap state densities compared to larger ( d = ∼5.5 nm) QDs.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-02-2020
Abstract: One challenge for efficient electrochemical reduction of carbon dioxide (CO 2 ) is that the gas is hydrophobic, but many of its desirable reactions require water (H 2 O). García de Arquer et al. addressed this problem by combining a copper electrocatalyst with an ionomer assembly that intersperses sulfonate-lined paths for the H 2 O with fluorocarbon channels for the CO 2 . The electrode architecture enables production of two-carbon products such as ethylene and ethanol at current densities just over an ere per square centimeter. Science , this issue p. 661
Publisher: American Chemical Society (ACS)
Date: 08-05-2019
DOI: 10.1021/JACS.9B02945
Abstract: The electrochemical reduction of CO
Publisher: Springer Science and Business Media LLC
Date: 03-12-2020
DOI: 10.1038/S41467-020-20004-7
Abstract: Electroreduction uses renewable energy to upgrade carbon dioxide to value-added chemicals and fuels. Renewable methane synthesized using such a route stands to be readily deployed using existing infrastructure for the distribution and utilization of natural gas. Here we design a suite of ligand-stabilized metal oxide clusters and find that these modulate carbon dioxide reduction pathways on a copper catalyst, enabling thereby a record activity for methane electroproduction. Density functional theory calculations show adsorbed hydrogen donation from clusters to copper active sites for the *CO hydrogenation pathway towards *CHO. We promote this effect via control over cluster size and composition and demonstrate the effect on metal oxides including cobalt(II), molybdenum(VI), tungsten(VI), nickel(II) and palladium(II) oxides. We report a carbon dioxide-to-methane faradaic efficiency of 60% at a partial current density to methane of 135 milli ere per square centimetre. We showcase operation over 18 h that retains a faradaic efficiency exceeding 55%.
Publisher: American Chemical Society (ACS)
Date: 15-12-2020
DOI: 10.1021/JACS.0C10774
Publisher: Springer Science and Business Media LLC
Date: 13-03-2023
Publisher: Springer Science and Business Media LLC
Date: 22-10-2019
DOI: 10.1038/S41467-019-12788-0
Abstract: The upgrading of CO 2 /CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage. Substantial progress has been made to improve performance at the cathodic side whereas less progress has been made on improving anodic electro-oxidation reactions to generate value. Here we report the efficient electroproduction of value-added multi-carbon dimethyl carbonate (DMC) from CO and methanol via oxidative carbonylation. We find that, compared to pure palladium controls, boron-doped palladium (Pd-B) tunes the binding strength of intermediates along this reaction pathway and favors DMC formation. We implement this doping strategy and report the selective electrosynthesis of DMC experimentally. We achieve a DMC Faradaic efficiency of 83 ± 5%, fully a 3x increase in performance compared to the corresponding pure Pd electrocatalyst.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 21-09-2018
Abstract: The high power conversion efficiencies of small-area perovskite solar cells (PSCs) have driven interest in the development of commercial devices. Rong et al. review recent progress in addressing stability, how to allow mass production, and how to maintain uniformity of large-area films. They note that lifetimes exceeding 10,000 hours under 1 sun (1 kW/m 2 ) illumination have been reported for printable triple mesoscopic PSCs. Science , this issue p. eaat8235
Publisher: American Chemical Society (ACS)
Date: 15-11-2021
Publisher: Springer Science and Business Media LLC
Date: 29-10-2018
Publisher: Springer Science and Business Media LLC
Date: 20-12-2019
DOI: 10.1038/S41467-019-13833-8
Abstract: Producing liquid fuels such as ethanol from CO 2 , H 2 O, and renewable electricity offers a route to store sustainable energy. The search for efficient electrocatalysts for the CO 2 reduction reaction relies on tuning the adsorption strength of carbonaceous intermediates. Here, we report a complementary approach in which we utilize hydroxide and oxide doping of a catalyst surface to tune the adsorbed hydrogen on Cu. Density functional theory studies indicate that this doping accelerates water dissociation and changes the hydrogen adsorption energy on Cu. We synthesize and investigate a suite of metal-hydroxide-interface-doped-Cu catalysts, and find that the most efficient, Ce(OH) x -doped-Cu, exhibits an ethanol Faradaic efficiency of 43% and a partial current density of 128 mA cm −2 . Mechanistic studies, wherein we combine investigation of hydrogen evolution performance with the results of operando Raman spectroscopy, show that adsorbed hydrogen hydrogenates surface *HCCOH, a key intermediate whose fate determines branching to ethanol versus ethylene.
Publisher: American Chemical Society (ACS)
Date: 14-09-2020
Publisher: Springer Science and Business Media LLC
Date: 05-10-2020
Publisher: American Chemical Society (ACS)
Date: 16-07-2019
Abstract: Continuous-wave (CW) lasing was recently achieved in colloidal quantum dots (CQDs) by lowering the threshold through the introduction of biaxial strain. However, the CW laser threshold is still much higher than the femtosecond threshold. This must be addressed before electrically injected lasing can be realized. Here we investigate the relationship between threshold and temperature and find a subpicosecond recombination process that proceeds very efficiently at temperatures reached during CW excitation. We combine density functional theory and molecular dynamics simulations to explore potential candidates for such a process, and find that crystal defects having thermally vibrating energy levels can become electronic traps-
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-06-2021
Abstract: Electrochemical reduction of carbon dioxide (CO 2 ) is a promising means of converting this greenhouse gas into valuable fuels and chemicals. However, two competing reactions restrict the efficiency of this process. In base, much of the CO 2 is trapped as carbonate before reduction in acid, protons outpace CO 2 at catching electrons from the cathode. Huang et al. report that a high dose of potassium ions can help to solve the latter problem. By concentrating potassium ions at the electrode, high selectivity toward CO 2 reduction at high current in acid is possible, which the authors attribute to electrostatic stabilization of the desired adsorbates. Science , abg6582, this issue p. 1074
Publisher: Springer Science and Business Media LLC
Date: 10-03-2020
Publisher: Springer Science and Business Media LLC
Date: 25-02-2020
Publisher: Springer Science and Business Media LLC
Date: 08-04-2019
DOI: 10.1038/S41467-019-09538-7
Abstract: The remarkable properties of metal halide perovskites arising from their impressive charge carrier diffusion lengths have led to rapid advances in solution-processed optoelectronics. Unfortunately, diffusion lengths reported in perovskite single crystals have ranged widely – from 3 μm to 3 mm – for ostensibly similar materials. Here we report a contactless method to measure the carrier mobility and further extract the diffusion length: our approach avoids both the effects of contact resistance and those of high electric field. We vary the density of quenchers – epitaxially included within perovskite single crystals – and report the dependence of excited state lifetime in the perovskite on inter-quencher spacing. Our results are repeatable and self-consistent (i.e. they agree on diffusion length for many different quencher concentrations) to within ± 6%. Using this method, we obtain a diffusion length in metal-halide perovskites of 2.6 μm ± 0.1 μm.
Publisher: Springer Science and Business Media LLC
Date: 24-11-2022
Publisher: Springer Science and Business Media LLC
Date: 11-05-2020
Publisher: Springer Science and Business Media LLC
Date: 18-12-2019
Publisher: Springer Science and Business Media LLC
Date: 20-09-2018
DOI: 10.1038/S41467-018-06311-0
Abstract: Copper-based materials are promising electrocatalysts for CO 2 reduction. Prior studies show that the mixture of copper (I) and copper (0) at the catalyst surface enhances multi-carbon products from CO 2 reduction however, the stable presence of copper (I) remains the subject of debate. Here we report a copper on copper (I) composite that stabilizes copper (I) during CO 2 reduction through the use of copper nitride as an underlying copper (I) species. We synthesize a copper-on-nitride catalyst that exhibits a Faradaic efficiency of 64 ± 2% for C 2+ products. We achieve a 40-fold enhancement in the ratio of C 2+ to the competing CH 4 compared to the case of pure copper. We further show that the copper-on-nitride catalyst performs stable CO 2 reduction over 30 h. Mechanistic studies suggest that the use of copper nitride contributes to reducing the CO dimerization energy barrier—a rate-limiting step in CO 2 reduction to multi-carbon products.
Publisher: American Chemical Society (ACS)
Date: 16-10-2023
Publisher: American Association for the Advancement of Science (AAAS)
Date: 16-10-2020
Abstract: Polymer-MOF hybrid enables simultaneous and uninterrupted sorption and release of atmospheric water.
Publisher: American Chemical Society (ACS)
Date: 17-11-2021
DOI: 10.1021/JACS.1C09515
Publisher: Springer Science and Business Media LLC
Date: 14-05-2021
DOI: 10.1038/S41467-021-23023-0
Abstract: Membrane electrode assembly (MEA) electrolyzers offer a means to scale up CO 2 -to-ethylene electroconversion using renewable electricity and close the anthropogenic carbon cycle. To date, excessive CO 2 coverage at the catalyst surface with limited active sites in MEA systems interferes with the carbon-carbon coupling reaction, diminishing ethylene production. With the aid of density functional theory calculations and spectroscopic analysis, here we report an oxide modulation strategy in which we introduce silica on Cu to create active Cu-SiO x interface sites, decreasing the formation energies of OCOH* and OCCOH*—key intermediates along the pathway to ethylene formation. We then synthesize the Cu-SiO x catalysts using one-pot coprecipitation and integrate the catalyst in a MEA electrolyzer. By tuning the CO 2 concentration, the Cu-SiO x catalyst based MEA electrolyzer shows high ethylene Faradaic efficiencies of up to 65% at high ethylene current densities of up to 215 mA cm −2 and features sustained operation over 50 h.
Publisher: Springer Science and Business Media LLC
Date: 18-05-2021
DOI: 10.1038/S41467-021-23065-4
Abstract: The electrochemical conversion of CO 2 to methane provides a means to store intermittent renewable electricity in the form of a carbon-neutral hydrocarbon fuel that benefits from an established global distribution network. The stability and selectivity of reported approaches reside below technoeconomic-related requirements. Membrane electrode assembly-based reactors offer a known path to stability however, highly alkaline conditions on the cathode favour C-C coupling and multi-carbon products. In computational studies herein, we find that copper in a low coordination number favours methane even under highly alkaline conditions. Experimentally, we develop a carbon nanoparticle moderator strategy that confines a copper-complex catalyst when employed in a membrane electrode assembly. In-situ XAS measurements confirm that increased carbon nanoparticle loadings can reduce the metallic copper coordination number. At a copper coordination number of 4.2 we demonstrate a CO 2 -to-methane selectivity of 62%, a methane partial current density of 136 mA cm −2 , and 110 hours of stable operation.
Publisher: American Chemical Society (ACS)
Date: 28-01-2020
DOI: 10.1021/JACS.9B12445
Abstract: The electroreduction of carbon dioxide (CO
Publisher: American Chemical Society (ACS)
Date: 10-06-2019
Publisher: American Chemical Society (ACS)
Date: 14-08-2020
Publisher: Springer Science and Business Media LLC
Date: 06-09-2021
DOI: 10.1038/S41377-021-00621-7
Abstract: While total internal reflection (TIR) lays the foundation for many important applications, foremost fibre optics that revolutionised information technologies, it is undesirable in some other applications such as light-emitting diodes (LEDs), which are a backbone for energy-efficient light sources. In the case of LEDs, TIR prevents photons from escaping the constituent high-index materials. Advances in material science have led to good efficiencies in generating photons from electron–hole pairs, making light extraction the bottleneck of the overall efficiency of LEDs. In recent years, the extraction efficiency has been improved, using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum. However, the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and time-consuming fabrication, which causes a gap between lab demonstration and industrial-level applications. Inspired by lightning bugs, we propose and realise a disordered metasurface for light extraction throughout the visible spectrum, achieved with single-step fabrication. By applying such a cost-effective light extraction layer, we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs, demonstrating a substantial potential for global energy-saving and sustainability.
Publisher: Springer Science and Business Media LLC
Date: 21-08-2023
Start Date: 12-2023
End Date: 12-2030
Amount: $34,956,464.00
Funder: Australian Research Council
View Funded Activity