Defect tolerance is a critical enabling factor for efficient lead-halide perovskite materials, but the current understanding is primarily on band-edge (cold) carriers, with significant debate over whether hot carriers can also exhibit defect tolerance. Here, this important gap in the field is addressed by investigating how intentionally-introduced traps affect hot carrier relaxation in CsPbX nanocrystals (X = Br, I, or mixture). Using femtosecond interband and intraband spectroscopy, along with energy-dependent photoluminescence measurements and kinetic modelling, it is found that hot carriers are not universally defect tolerant in CsPbX, but are strongly correlated to the defect tolerance of cold carriers, requiring shallow traps to be present (as in CsPbI).
View Article and Find Full Text PDFAn integrated textile electronic system is reported here, enabling a truly free form factor system via textile manufacturing integration of fiber-based electronic components. Intelligent and smart systems require freedom of form factor, unrestricted design, and unlimited scale. Initial attempts to develop conductive fibers and textile electronics failed to achieve reliable integration and performance required for industrial-scale manufacturing of technical textiles by standard weaving technologies.
View Article and Find Full Text PDFInP quantum dots (QDs) are attracting significant interest as a potentially less toxic alternative to Cd-based QDs in many research areas. Although InP-based core/shell QDs with excellent photoluminescence properties have been reported so far, sophisticated interface treatment to eliminate defects is often necessary. Herein, using aminophosphine as a seeding source of phosphorus, we find that HS can be efficiently generated from the reaction between a thiol and an alkylamine at high temperatures.
View Article and Find Full Text PDFWe propose a computational design framework to design the architecture of a white lighting system having multiple pixelated patterns of electric-field-driven quantum dot light-emitting diodes. The quantum dot of the white lighting system has been optimised by a system-level combinatorial colour optimisation process with the Nelder-Mead algorithm used for machine learning. The layout of quantum dot patterns is designed precisely using rigorous device-level charge transport simulation with an electric-field dependent charge injection model.
View Article and Find Full Text PDFSmart textiles consist of discrete devices fabricated from-or incorporated onto-fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report the realisation of a fully operational 46-inch smart textile lighting/display system consisting of RGB fibrous LEDs coupled with multifunctional fibre devices that are capable of wireless power transmission, touch sensing, photodetection, environmental/biosignal monitoring, and energy storage.
View Article and Find Full Text PDFQuantum dot light-emitting diodes (QD-LEDs) are widely recognised as great alternatives to organic light-emitting diodes (OLEDs) due to their enhanced performances. This focus article surveys the current progress on the state-of-the-art QD-LED technology including material synthesis, device optimization and innovative fabrication processes. A discussion on the material synthesis of core nanocrystals, shell layers and surface-binding ligands is presented for high photoluminescence quantum yield (PLQY) quantum dots (QDs) using heavy-metal free materials.
View Article and Find Full Text PDFChem Commun (Camb)
November 2020
Alkaline-earth metal Ca modified CdS nanocrystals have been designed for the first time for highly efficient H evolution from hydrogen sulfide (HS) with NaSO as a favourable reaction medium. The advantage of NaSO was revealed by an electrochemical test, and the conversion of NaSO during the reaction was carefully studied. Particularly, most of NaSO was converted into NaSO.
View Article and Find Full Text PDFWe report on the design, fabrication, and characterization of heterostructure In-Zn-O (IZO) thin-film transistors (TFTs) with improved performance characteristics and robust operation. The heterostructure layer is fabricated by stacking a solution-processed IZO film on top of a buffer layer, which is deposited previously using an electron beam (e-beam) evaporator. A thin buffer layer at the dielectric interface can help to template the structure of the channel.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
March 2019
Structural designs combining oligoparaphenylene-derived nanohoops with other functional organic building blocks should lead to novel molecular architectures with intriguing properties. Herein, we describe the synthesis of a pentiptycene-derived chiral dual nanohoop molecule with key steps including ring expansion through dianthracene cycloreversion and transannular [4+2] cycloaddition across a 64-membered macrocycle. The crystal structure of the nanohoop molecule displays an ordered packing pattern with long-range channels in the solid state.
View Article and Find Full Text PDFSemiconducting quantum dots (QDs) have recently triggered a huge interest in constructing efficient hydrogen production systems. It is well established that a large fraction of surface atoms of QDs need ligands to stabilize and avoid them from aggregating. However, the influence of the surface property of QDs on photocatalysis is rather elusive.
View Article and Find Full Text PDFPhotocatalytic hydrogen evolution is a promising technique for the direct conversion of solar energy into chemical fuels. Colloidal quantum dots with tunable band gap and versatile surface properties remain among the most prominent targets in photocatalysis despite their frequent toxicity, which is detrimental for environmentally friendly technological implementations. In the present work, all-inorganic sulfide-capped InP and InP/ZnS quantum dots are introduced as competitive and far less toxic alternatives for photocatalytic hydrogen evolution in aqueous solution, reaching turnover numbers up to 128,000 based on quantum dots with a maximum internal quantum yield of 31%.
View Article and Find Full Text PDFUnlike their bulk counterpart, Cu In S quantum dots (QDs) prepared by an aqueous synthetic approach, show promising activity for photocatalytic hydrogen evolution, which is competitive with the state-of-the-art Cd chalcogen QDs. Moreover, the as-prepared Cu In S QDs with In-rich composition show much better efficiency than the stoichiometric ones (Cu/In=1:1).
View Article and Find Full Text PDFSelective oxidation of alcohols to aldehydes/ketones has been achieved with the help of 3-mercaptopropionic acid (MPA)-capped CdSe quantum dot (MPA-CdSe QD) and visible light. Visible-light-prompted electron-transfer reaction initiates the oxidation. The thiyl radical generated from the thiolate anion adsorbed on a CdSe QD plays a key role by abstracting the hydrogen atom from the C-H bond of the alcohol (R CH(OH)R ).
View Article and Find Full Text PDFX-ray transient absorption spectroscopy (XTA) and optical transient spectroscopy (OTA) were used to probe the Co(I) intermediate generated in situ from an aqueous photocatalytic hydrogen evolution system, with [Ru(bpy)]Cl·6HO as the photosensitizer, ascorbic acid/ascorbate as the electron donor, and the Co-polypyridyl complex ([Co(DPA-Bpy)Cl]Cl) as the precatalyst. Upon exposure to light, the XTA measured at Co K-edge visualizes the grow and decay of the Co(I) intermediate, and reveals its Co-N bond contraction of 0.09 ± 0.
View Article and Find Full Text PDFThe century-old yet synthetically underexplored anthracene photodimerization-cycloreversion reactions have been employed as the key steps to access highly strained aromatic hydrocarbons. Herein we report the chemical syntheses of oligoparaphenylene-derived nanohoops in five steps or less featuring a rigid dianthracene synthon. The newly synthesized nanohoops display intriguing experimental and computational properties.
View Article and Find Full Text PDFA visible-light-induced hydrogen evolution system based on a CdSe quantum dots (QDs)-TiO2 -Ni(OH)2 ternary assembly has been constructed under an ambient environment, and a bifunctional molecular linker, mercaptopropionic acid, is used to facilitate the interaction between CdSe QDs and TiO2 . This hydrogen evolution system works effectively in a basic aqueous solution (pH 11.0) to achieve a hydrogen evolution rate of 10.
View Article and Find Full Text PDFHollow spheres are one of the most promising micro-/nanostructures because of their unique performance in diverse applications. Templates, surfactants, and structure-directing agents are often used to control the sizes and morphologies of hollow spheres. In this Article, we describe a simple method based on visible light catalysis for preparing hollow nanospheres from CdE (E = Te, Se, and S) quantum dots (QDs) and nickel (Ni(2+)) salts in aqueous media.
View Article and Find Full Text PDFNatural photosynthesis offers the concept of storing sunlight in chemical form as hydrogen (H2), using biomass and water. Herein we describe a robust artificial photocatalyst, nickel-hybrid CdS quantum dots (Nih-CdS QDs) made in situ from nickel salts and CdS QDs stabilized by 3-mercaptopropionic acid, for visible-light-driven H2 evolution from glycerol and water. With visible light irradiation for 20 h, 403.
View Article and Find Full Text PDFA novel hybrid Nih -CdSe/CdS core/shell quantum dot is a simple and exceptional artificial photocatalyst for H2 production from 2-propanol aqueous solution. Studies on the nature of the artificial photocatalyst and mechanism for H2 production demonstrate that the synthetic strategy is general and the artificial photocatalyst holds promise for light capture, electron transfer, and catalysis at the surface of the Nih -CdSe/CdS core/shell quantum dots, leading to a self-healing system for H2 evolution in harmony.
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