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Showing papers on "Quantum dot published in 2022"


Journal ArticleDOI
21 Jan 2022-Science
TL;DR: Replacing the commonly used mesoporous–titanium dioxide electron transport layer with a thin layer of polyacrylic acid–stabilized tin(IV) oxide quantum dots enhanced light capture and largely suppressed nonradiative recombination at the ETL–perovskite interface, resulting in a certified power conversion efficiency of 25.4% and high operational stability.
Abstract: Improvements to perovskite solar cells (PSCs) have focused on increasing their power conversion efficiency (PCE) and operational stability and maintaining high performance upon scale-up to module sizes. We report that replacing the commonly used mesoporous–titanium dioxide electron transport layer (ETL) with a thin layer of polyacrylic acid–stabilized tin(IV) oxide quantum dots (paa-QD-SnO2) on the compact–titanium dioxide enhanced light capture and largely suppressed nonradiative recombination at the ETL–perovskite interface. The use of paa-QD-SnO2 as electron-selective contact enabled PSCs (0.08 square centimeters) with a PCE of 25.7% (certified 25.4%) and high operational stability and facilitated the scale-up of the PSCs to larger areas. PCEs of 23.3, 21.7, and 20.6% were achieved for PSCs with active areas of 1, 20, and 64 square centimeters, respectively. Description Tailoring tin oxide layers Mesoporous titanium dioxide is commonly used as the electron transport layer in perovskite solar cells, but electron transport layers based on tin(IV) oxide quantum dots could be more efficient, with a better-aligned conduction band and a higher carrier mobility. Kim et al. show that such quantum dots could conformally coat a textured fluorine-doped tin oxide electrode when stabilized with polyacrylic acid. Improved light trapping and reduced nonradiative recombination resulted in a certified power conversion efficiency of 25.4% and high operational stability. In larger-area minimodules, active areas as high as 64 square centimeters maintained certified power conversion efficiencies of more than 20%. —PDS Polymer-stabilized tin oxide nanoparticles suppress recombination at the electron-transport layer–perovskite interface.

631 citations


Journal ArticleDOI
TL;DR: In this paper , tetra (4-carboxyphenyl) porphyrin (TCPP) and graphene quantum dots (GQDs) were loaded on the surface of Bi2MoO6 (BMO) to fabricate novel Z-scheme heterojunctions of TCPP/G/BMO.

115 citations


Journal ArticleDOI
TL;DR: In this article , a metal-free boron nitride quantum dots (BNQDs) and graphitic carbon nitride (C3N4) heterostructure was designed as an effective and durable NRR catalyst.

80 citations


Journal ArticleDOI
TL;DR: In this paper, a metal-free boron nitride quantum dots (BNQDs) and graphitic carbon nitride (C3N4) heterostructure was designed as an effective and durable NRR catalyst.

80 citations


Journal ArticleDOI
TL;DR: In this paper , a CsPbBr3 QD-in-perovskite matrix solids that enable high luminescent efficiency and spectral stability with an optical gap of over 2.6 eV was developed.
Abstract: The epitaxial growth of a perovskite matrix on quantum dots (QDs) has enabled the emergence of efficient red light-emitting diodes (LEDs) because it unites efficient charge transport with strong surface passivation. However, the synthesis of wide-band gap (Eg) QD-in-matrix heterostructures has so far remained elusive in the case of sky-blue LEDs. Here, we developed CsPbBr3 QD-in-perovskite matrix solids that enable high luminescent efficiency and spectral stability with an optical Eg of over 2.6 eV. We screened alloy candidates that modulate the perovskite Eg and allow heteroepitaxy, seeking to implement lattice-matched type-I band alignment. Specifically, we introduced a CsPb1-xSrxBr3 matrix, in which alloying with Sr2+ increased the Eg of the perovskite and minimized lattice mismatch. We then developed an approach to passivation that would overcome the hygroscopic nature of Sr2+. We found that bis(4-fluorophenyl)phenylphosphine oxide strongly coordinates with Sr2+ and provides steric hindrance to block H2O, a finding obtained by combining molecular dynamics simulations with experimental results. The resulting QD-in-matrix solids exhibit enhanced air- and photo-stability with efficient charge transport from the matrix to the QDs. LEDs made from this material exhibit an external quantum efficiency of 13.8% and a brightness exceeding 6000 cd m-2.

70 citations


Journal ArticleDOI
TL;DR: In this paper , the photoluminescence (PL) mechanism of carbon dots (CDs) remains unclear due to the complex core-shell structure and variety of surface functional groups.
Abstract: Abstract Due to the complex core–shell structure and variety of surface functional groups, the photoluminescence (PL) mechanism of carbon dots (CDs) remain unclear. o-Phenylenediamine (oPD), as one of the most common precursors for preparing red emissive CDs, has been extensively studied. Interestingly, most of the red emission CDs based on oPD have similar PL emission characteristics. Herein, we prepared six different oPD-based CDs and found that they had almost the same PL emission and absorption spectra after purification. Structural and spectral characterization indicated that they had similar carbon core structures but different surface polymer shells. Furthermore, single-molecule PL spectroscopy confirmed that the multi-modal emission of those CDs originated from the transitions of different vibrational energy levels of the same PL center in the carbon core. In addition, the phenomenon of “spectral splitting” of single-particle CDs was observed at low temperature, which confirmed these oPD-based CDs were unique materials with properties of both organic molecules and quantum dots. Finally, theoretical calculations revealed their potential polymerization mode and carbon core structure. Moreover, we proposed the PL mechanism of red-emitting CDs based on oPD precursors; that is, the carbon core regulates the PL emission, and the polymer shell regulates the PL intensity. Our work resolves the controversy on the PL mechanism of oPD-based red CDs. These findings provide a general guide for the mechanism exploration and structural analysis of other types of CDs.

68 citations


Journal ArticleDOI
TL;DR: In this article , the electronic band structure of SnO2 QDs is modified by Mo dopants, which reduce the band gap by changing the position of the conduction band edge.
Abstract: Functional nanomaterials are desirable in the sustainable photocatalytic degradation of antibiotic contaminants, but the development of nanostructured photocatalysts is facing fatal challenges not only in synthesis strategies but also in property control. Herein, a facile synthesis strategy is accomplished by the green synthesis of SnO2 quantum dots (QDs) engineered by Mo modification. The effects of Mo incorporation on the microstructural, compositional, electrical and optical properties are discussed. The electronic band structure of SnO2 QDs is modified by Mo dopants, which reduce the band gap by changing the position of the conduction band edge. The Mo-modified band structure provides the SnO2 QDs with visible-light driven photocatalytic abilities in the removal of antibiotics as emerging organic contaminants. The nanostructured photocatalysts exhibit proficient performances in the degradation of tetracycline hydrochloride. The degradation efficiency is up to 96.5% when the antibiotic concentration is 25 mg/L and the rate constant is 0.033 min−1. The hydroxyl radicals, produced by the oxidation of water, are determined to be the main active species in the photocatalytic process. The valence band edge over 3 eV guarantees the strong oxidizing abilities of photogenerated holes to create highly active hydroxyl radicals for the efficient photocatalytic degradation. First principle calculations based on the density functional theory reveal the mechanism of Mo modification, illustrating that Mo 4d electrons extend the conduction band edge to the Fermi level. The present work provides a green synthesis strategy and mechanism insights for band structure modification of SnO2 QDs as proficient visible-light driven photocatalysts for environmental remediation.

66 citations


Journal ArticleDOI
TL;DR: In this article , the photoluminescence (PL) mechanism of carbon dots (CDs) remains unclear due to the complex core-shell structure and variety of surface functional groups.
Abstract: Abstract Due to the complex core–shell structure and variety of surface functional groups, the photoluminescence (PL) mechanism of carbon dots (CDs) remain unclear. o-Phenylenediamine (oPD), as one of the most common precursors for preparing red emissive CDs, has been extensively studied. Interestingly, most of the red emission CDs based on oPD have similar PL emission characteristics. Herein, we prepared six different oPD-based CDs and found that they had almost the same PL emission and absorption spectra after purification. Structural and spectral characterization indicated that they had similar carbon core structures but different surface polymer shells. Furthermore, single-molecule PL spectroscopy confirmed that the multi-modal emission of those CDs originated from the transitions of different vibrational energy levels of the same PL center in the carbon core. In addition, the phenomenon of “spectral splitting” of single-particle CDs was observed at low temperature, which confirmed these oPD-based CDs were unique materials with properties of both organic molecules and quantum dots. Finally, theoretical calculations revealed their potential polymerization mode and carbon core structure. Moreover, we proposed the PL mechanism of red-emitting CDs based on oPD precursors; that is, the carbon core regulates the PL emission, and the polymer shell regulates the PL intensity. Our work resolves the controversy on the PL mechanism of oPD-based red CDs. These findings provide a general guide for the mechanism exploration and structural analysis of other types of CDs.

66 citations


Journal ArticleDOI
TL;DR: In this article , a hole-transport polymers with simultaneous low electron affinity and reduced energetic disorder is used to eliminate electron leakage at the organic/inorganic interface for green and blue quantum-dot light-emitting diodes.
Abstract: Quantum-dot light-emitting diodes (QD-LEDs) promise a new generation of efficient, low-cost, large-area and flexible electroluminescent devices. However, the inferior performance of green and blue QD-LEDs compared with their red counterpart is hindering the commercialization of QD-LEDs in display and solid-state lighting applications. Here we demonstrate green and blue QD-LEDs with ~100% conversion of the injected charge carriers into emissive excitons. The key to success is the elimination of electron leakage at the organic/inorganic interface by using hole-transport polymers with simultaneous low electron affinity and reduced energetic disorder. Our devices exhibit high external quantum efficiencies over a wide range of luminance values (peak external quantum efficiencies of 28.7% for green and 21.9% for blue) and excellent stability (extrapolated T95 lifetime is 580,000 h for green and 4,400 h for blue QD-LEDs). We expect our work to provide a general strategy for eliminating charge leakage in solution-processed LEDs featuring organic/inorganic interfaces. A new strategy to reduce charge leakage in quantum-dot light-emitting diodes enables high external quantum efficiencies of 28.7% and 21.9% and excellent T95 lifetimes of 580,000 h and 4,400 h for green and blue devices, respectively.

65 citations


Journal ArticleDOI
TL;DR: In this paper, a zero-dimensional (0D) Bi3TaOO7 (BTO) quantum dots/three-dimensional onion-ring-like g-C3N4 (OR-CN) S-scheme heterojunction catalyst is constructed to simulate the production of hydrogen by photocatalysis under sunlight irradiation through a solvothermal method for photocatalytic hydrogen production under visible light irradiation.

64 citations


Journal ArticleDOI
TL;DR: In this paper , a simple strategy to synthesize excellent stability and efficient emission of CsPbBr3 QDs by using 2-hexyldecanoic acid (DA) as a ligand to replace the regular oleic acid ligand was proposed.
Abstract: All-inorganic CsPbBr3 perovskite quantum dots (QDs) have received great attention in white light emission because of their outstanding properties. However, their practical application is hindered by poor stability. Herein, we propose a simple strategy to synthesize excellent stability and efficient emission of CsPbBr3 QDs by using 2-hexyldecanoic acid (DA) as a ligand to replace the regular oleic acid (OA) ligand. Thanks to the strong binding energy between DA ligand and QDs, the modified QDs not only show a high photoluminescence quantum yield (PLQY) of 96% but also exhibit high stability against ethanol and water. Thereby warm white light-emitting diodes (WLEDs) are constructed by combining ligand modified CsPbBr3 QDs with red AgInZnS QDs on blue emitting InGaN chips, exhibiting a color rendering index of 93, a power efficiency of 64.8 lm/W, a CIE coordinate of (0.44, 0.42) and correlated color temperature value of 3018 K. In addition, WLEDs based on ligand modified CsPbBr3 QDs also exhibit better thermal performance than that of WLEDs based on the regular CsPbBr3 QDs. The combination of improved efficiency and better thermal stability with high color quality indicates that the modified CsPbBr3 QDs are ideal for WLEDs application.

Journal ArticleDOI
TL;DR: In this paper , a 0D/3D S-scheme heterojunction photocatalyst was constructed to simulate the production of hydrogen by photocatalysis under sunlight irradiation through a solvothermal method for hydrogen production under visible light irradiation.

Journal ArticleDOI
TL;DR: In this paper , an efficient approach is demonstrated to produce low-dimensional Pt/graphene−carbon nanofibers (CNFs)based heterostructures for bias-free, highly efficient, and durable hydrogen evolution reaction (HER) in large scale solar-driven hydrogen production.
Abstract: Large scale solar‐driven hydrogen production is a crucial step toward decarbonizing society. However, the solar‐to‐hydrogen (STH) conversion efficiency, long‐term stability, and cost‐effectiveness in hydrogen evolution reaction (HER) still need to be improved. Herein, an efficient approach is demonstrated to produce low‐dimensional Pt/graphene‐carbon nanofibers (CNFs)‐based heterostructures for bias‐free, highly efficient, and durable HER. Carbon dots are used as efficient building blocks for the in situ formation of graphene along the CNFs surface. The presence of graphene enhances the electronic conductivity of CNFs to ≈3013.5 S m−1 and simultaneously supports the uniform Pt clusters growth and efficient electron transport during HER. The electrode with a low Pt loading amount (3.4 µg cm−2) exhibits a remarkable mass activity of HER in both acidic and alkaline media, which is significantly better than that of commercial Pt/C (31 µg cm−2 of Pt loading). In addition, using a luminescent solar concentrator‐coupled solar cell to provide voltage, the bias‐free water splitting system exhibits an STH efficiency of 0.22% upon one‐sun illumination. These results are promising toward using low‐dimensional heterostructured catalysts for future energy storage and conversion applications.

Journal ArticleDOI
TL;DR: In this article , an innovative PEC biosensor combined with quantum size-controlled engineering based on quantum confinement by controlling the quantum size was designed for the detection of human papillomavirus-16 (HPV-16) through CRISPR-Cas12a (Cpf1)-induced disassembly of Z-scheme heterojunction.
Abstract: Photoelectrochemical (PEC) biosensors incorporating biomolecular recognition with photon-to-electron conversion capabilities of the photoactive species have been developed for molecular diagnosis, but most involve difficulty in adjusting band gap positions and are unsuitable for PEC biodetection. In this work, an innovative PEC biosensor combined with quantum size-controlled engineering based on quantum confinement by controlling the quantum size was designed for the detection of human papillomavirus-16 (HPV-16) through CRISPR-Cas12a (Cpf1)-induced disassembly of Z-scheme heterojunction. To the best of our knowledge, quantum size-controlled engineering that precisely tunes the properties of photoactive materials is first utilized in the PEC bioanalysis. Based on the quantum size effect, the light absorption efficiency and charge-transfer rate were tuned to suitable levels to obtain the best PEC performance. After incubation with target HPV-16, the binding of Cas12a-crRNA to the target double-stranded DNA (dsDNA) stimulated the activity of indiscriminate cleavage toward single-stranded DNA (ssDNA), resulting in a decrease in photocurrent due to the blocking of electron transfer through the heterojunction. By optimizing experimental conditions, the Z-scheme sensing system exhibited incredible photocurrent response to HPV-16 in the range from 3.0 pM to 600 nM with a detection limit of 1.0 pM. Impressively, the application of the quantum size effect could stimulate more interest in the precise design of band gap structure to improve PEC performance.

Journal ArticleDOI
TL;DR: In this article, a 0D Cu-Fe bi-metal oxide QDs/2D g-C3N4 (CNNSs) was fabricated via a facile one-step synthesis strategy for photo-Fenton catalysis.
Abstract: Exploitation of catalysts with multi-active sites is very important for enhancing catalytic performance. 0D/2D hybrids, especially quantum dots (QDs)/nanosheets (NSs), have attracted increasing attentions for advanced oxidation processes due to high charge mobility and more active sites. However, 0D/2D hybrids with multi-active sites still remain a great challenge. Herein, 0D Cu-Fe bi-metal oxide QDs/2D g-C3N4 (CNNSs) exhibiting superior advantages beyond single-metal 0D/2D counterparts was fabricated via a facile one-step synthesis strategy for photo-Fenton catalysis. The synergy of ultrafine Cu-Fe sites on CNNSs led to outstanding tetracycline removal efficiency over a wide pH range. Our experiments and DFT calculations clearly demonstrated that except for the fast charge separation and transfer, this synergy could achieve the optimal H2O2 adsorption-activation trade-off on Cu-Fe sites, while also modify tetracycline absorption, leading to multiple synergies of adsorption-catalytic degradation and photocatalysis-Fenton oxidation. This work provides new insights in developing multi-functional 0D/2D hybrids for environment and energy applications.

Journal ArticleDOI
TL;DR: In this paper , the authors outline the latest achievements of quantum dots and their composites materials in those energy storage applications and rationally analyze the shortcomings of quantum dot in energy storage and conversion, and predict the future development trend, challenges, and opportunities.
Abstract: Abstract The environmental problems of global warming and fossil fuel depletion are increasingly severe, and the demand for energy conversion and storage is increasing. Ecological issues such as global warming and fossil fuel depletion are increasingly stringent, increasing energy conversion and storage needs. The rapid development of clean energy, such as solar energy, wind energy and hydrogen energy, is expected to be the key to solve the energy problem. Several excellent literature works have highlighted quantum dots in supercapacitors, lithium-sulfur batteries, and photocatalytic hydrogen production. Here, we outline the latest achievements of quantum dots and their composites materials in those energy storage applications. Moreover, we rationally analyze the shortcomings of quantum dots in energy storage and conversion, and predict the future development trend, challenges, and opportunities of quantum dots research.

Journal ArticleDOI
TL;DR: In this paper , a tailor-made ternary halogen-free solvent (naphthene, n−tridecane, and n−nonane) recipe was proposed for CsPbX3 perovskite QDs and their corresponding inkjet-printed QLEDs.
Abstract: Toward next‐generation electroluminescent quantum dot (QD) displays, inkjet printing technique has been convinced as one of the most promising low‐cost and large‐scale manufacturing of patterned quantum dot light‐emitting diodes (QLEDs). The development of high‐quality and stable QD inks is a key step to push this technology toward practical applications. Herein, a universal ternary‐solvent‐ink strategy is proposed for the cesium lead halides (CsPbX3) perovskite QDs and their corresponding inkjet‐printed QLEDs. With this tailor‐made ternary halogen‐free solvent (naphthene, n‐tridecane, and n‐nonane) recipe, a highly dispersive and stable CsPbX3 QD ink is obtained, which exhibits much better printability and film‐forming ability than that of the binary solvent (naphthene and n‐tridecane) system, leading to a much better qualitied perovskite QD thin film. Consequently, a record peak external quantum efficiency (EQE) of 8.54% and maximum luminance of 43 883.39 cd m−2 is achieved in inkjet‐printed green perovskite QLEDs, which is much higher than that of the binary‐solvent‐system‐based devices (EQE = 2.26%). Moreover, the ternary‐solvent‐system exhibits a universal applicability in the inkjet‐printed red and blue perovskite QLEDs as well as cadmium (Cd)‐based QLEDs. This work demonstrates a new strategy for tailor‐making a general ternary‐solvent‐QD‐ink system for efficient inkjet‐printed QLEDs as well as the other solution‐processed electronic devices in the future.

Journal ArticleDOI
TL;DR: In this paper , a novel dual Z-scheme tandem CQD-MnIn2S4/Cu2O/Ag2O interface was fabricated via hydrothermal method for MO removal and E. coli disinfection under visible light illumination.

Journal ArticleDOI
TL;DR: In this article, a ternary photocatalyst is constructed using Cu-In-Zn-S quantum dots (CIZS QDs), MoS2 and carbon dots (CDs).
Abstract: Visible-driven photocatalysis plays a critical role in solar energy conversion, but the efficiency is limited by the poor charge separation and utilization. Here, a ternary photocatalyst is constructed using Cu-In-Zn-S quantum dots (CIZS QDs), MoS2 and carbon dots (CDs). Interestingly, transient photovoltage measurements confirm that MoS2 has no assistance on the charge extraction rate, whereas CDs dramatically increases the attenuation constant of the charge recombination process (from 0.178 to 0.260 ms) due to its electron sinking effect. The optimal hydrogen production rate of CIZS/MoS2/CDs reaches 3706 μmol g-1 h-1, which is 6.65 and 148.24 times to that of CIZS QDs and MoS2, respectively. Further electrocatalytic tests indicate that MoS2 is the main place for hydrogen evolution reaction, whereas CIZS and CDs are responsible for light harvesting and charge sinking, respectively. This work provides a useful guideline for the synergy of charge extraction and utilization process in composite photocatalyst design.

Journal ArticleDOI
TL;DR: In this paper , a new method was utilized for epitaxial growth of gold quantum dots using atomically platinum chlorine species with porous graphdiyne as a support (PtCl2Au(111)/GDY), for obtaining successful multicomponent quantum dots with a size of 2.37 nm.
Abstract: The development of efficient and durable electrocatalysts is the only way to achieve commercial fuel cells. A new, efficient method was utilized for epitaxial growth of gold quantum dots using atomically platinum chlorine species with porous graphdiyne as a support (PtCl2Au(111)/GDY), for obtaining successful multicomponent quantum dots with a size of 2.37 nm. The electrocatalyst showed a high mass activity of 175.64 A mgPt-1 for methanol oxidation reactions (MORs) and 165.35 A mgPt-1 for ethanol oxidation reactions (EORs). The data for this experiment are 85.67 and 246.80 times higher than those of commercial Pt/C, respectively. The catalyst also showed highly robust stability for MORs with negligible specific activity decay after 110 h at 10 mA cm-2. Both structure characterizations and theoretical calculations reveal that the excellent catalytic performance can be ascribed to the chlorine introduced to modify the d-band structure on the Pt surface and suppression of the CO poisoning pathway of the MOR. Our results indicate that an atomically dispersed metal species tailoring strategy opens up a new path for the efficient design of highly active and stable catalysts.


Journal ArticleDOI
TL;DR: In this article, a simple method to anchor CN quantum dots (QDs) onto g-C3N4 nanosheets to form a homojunction structure (HJ-C 3N4), which could improve photocatalytic performance largely without introducing metal elements.
Abstract: Polymeric carbon nitride (C3N4) is a very attractive candidate to produce photocatalytic hydrogen peroxide (H2O2) due to its low-cost, metal-free characteristics. However, the low efficiency would limit its development to higher yields because of insufficient light absorption and electron-hole separation. Here, we developed a simple method to anchor CN quantum dots (QDs) onto g-C3N4 nanosheets to form a homojunction structure (HJ-C3N4), which could improve photocatalytic performance largely without introducing metal elements. Its superior efficiency is a result of the band alignment by the homojunction structure providing excellent electron-hole separation and QDs providing suppressed recombination. Simultaneously, the light responsiveness of QDs endows a wide spectrum-responsive adsorption and enhances the adsorption intensity. The H2O2 yield of the HJ-C3N4 reached 115 μmol·L−1·h−1 in pure water by visible light, which has an 8.6x higher production than g-C3N4 nanosheets. The material design of 0D/2D homojunction could be extended to other materials with specific band alignment.

Journal ArticleDOI
08 Sep 2022-Science
TL;DR: In this paper , a room-temperature synthesis of monodisperse, isolable, spheroidal APbBr3 QDs with size tunable from 3 to > 13 nanometers was reported.
Abstract: Colloidal lead halide perovskite nanocrystals are of interest as photoluminescent quantum dots (QDs) whose properties depend on the size and shape. They are normally synthesized on subsecond time scales through hard-to-control ionic metathesis reactions. We report a room-temperature synthesis of monodisperse, isolable, spheroidal APbBr3 QDs (“A” indicates cesium, formamidinium, and methylammonium) that are size tunable from 3 to >13 nanometers. The kinetics of both nucleation and growth are temporally separated and substantially slowed down by the intricate equilibrium between the precursor (PbBr2) and the A[PbBr3] solute, with the latter serving as a monomer. QDs of all these compositions exhibit up to four excitonic transitions in their linear absorption spectra, and we demonstrate that the size-dependent confinement energy for all transitions is independent of the A-site cation. Description Slowing nanoparticle growth Inorganic materials with more covalent bonding, such as cadmium selenide, form uniform nanoparticles under fast growth conditions, but perovskites such as cesium lead bromide (CsPbBr3) are more ionic and grow rapidly to form larger nanoparticles. Akkerman et al. controlled the nanoparticles’ growth kinetics by using trioctylphosphine oxide, which solubilized the PbBr2 precursor, bound to the cation-[PbBr3] monomer (solute), and weakly coordinated to the crystal nuclei surfaces. Nanoparticles with diameters from 3 to 13 nanometers were stabilized and isolated in high yield with lecithin, a long-chain zwitterion. Four well-resolved excitonic transitions with size-dependent confinement energies were seen for cesium as well as organic cations. —PDS Monodisperse lead-halide perovskite nanocrystals are synthesized through slow and temporally separated nucleation and growth.

Journal ArticleDOI
TL;DR: In this article, an electrochemically stable Zn-ion battery with vanadium cathode was designed by manipulating nucleation process through the introduction of hydrophilic graphene quantum dots (GQDs).

Journal ArticleDOI
TL;DR: In this paper , a 0D Cu-Fe bi-metal oxide QDs/2D g-C3N4 (CNNSs) was fabricated via a facile one-step synthesis strategy for photo-Fenton catalysis.
Abstract: Exploitation of catalysts with multi-active sites is very important for enhancing catalytic performance. 0D/2D hybrids, especially quantum dots (QDs)/nanosheets (NSs), have attracted increasing attentions for advanced oxidation processes due to high charge mobility and more active sites. However, 0D/2D hybrids with multi-active sites still remain a great challenge. Herein, 0D Cu-Fe bi-metal oxide QDs/2D g-C3N4 (CNNSs) exhibiting superior advantages beyond single-metal 0D/2D counterparts was fabricated via a facile one-step synthesis strategy for photo-Fenton catalysis. The synergy of ultrafine Cu-Fe sites on CNNSs led to outstanding tetracycline removal efficiency over a wide pH range. Our experiments and DFT calculations clearly demonstrated that except for the fast charge separation and transfer, this synergy could achieve the optimal H2O2 adsorption-activation trade-off on Cu-Fe sites, while also modify tetracycline absorption, leading to multiple synergies of adsorption-catalytic degradation and photocatalysis-Fenton oxidation. This work provides new insights in developing multi-functional 0D/2D hybrids for environment and energy applications.

Journal ArticleDOI
TL;DR: In this paper , an electrochemically stable Zn anode was designed by manipulating nucleation process through the introduction of hydrophilic graphene quantum dots (GQDs), which is aroused from the lower electronegativity of GQDs, which is conducive to accelerating uniform Zn deposition, resulting in the robust Zn ion anode without dendrites.


Journal ArticleDOI
TL;DR: In this article , a ternary photocatalyst is constructed using Cu-In-Zn-S quantum dots (CIZS QDs), MoS2 and carbon dots (CDs).
Abstract: Visible-driven photocatalysis plays a critical role in solar energy conversion, but the efficiency is limited by the poor charge separation and utilization. Here, a ternary photocatalyst is constructed using Cu-In-Zn-S quantum dots (CIZS QDs), MoS2 and carbon dots (CDs). Interestingly, transient photovoltage measurements confirm that MoS2 has no assistance on the charge extraction rate, whereas CDs dramatically increases the attenuation constant of the charge recombination process (from 0.178 to 0.260 ms) due to its electron sinking effect. The optimal hydrogen production rate of CIZS/MoS2/CDs reaches 3706 μmol g-1 h-1, which is 6.65 and 148.24 times to that of CIZS QDs and MoS2, respectively. Further electrocatalytic tests indicate that MoS2 is the main place for hydrogen evolution reaction, whereas CIZS and CDs are responsible for light harvesting and charge sinking, respectively. This work provides a useful guideline for the synergy of charge extraction and utilization process in composite photocatalyst design.


Journal ArticleDOI
TL;DR: In this article , the potential of Cs2CuBr4 PQDs as a platform for highly efficient CO2 photoreduction and provided a distinct concept for CO2 adsorption and activation based on the catalytic mechanism of Cu-based PQD.
Abstract: Lead (Pb) halide perovskite quantum dots (PQDs) are promising candidates for the photochemical reduction of CO2. However, the intrinsically weak adsorption and activation toward inert CO2 molecules have seriously hindered their practical application. This study reports alternative Cs2CuBr4 PQDs for gas–solid phase photocatalytic CO2 reduction under simulated solar irradiation. Cs2CuBr4 PQDs exhibited CO2 photoreduction performance with CH4 and CO yields of 74.81 and 148.98 μmol g–1, respectively. In situ diffuse reflectance infrared Fourier transform spectra and density functional theory calculations cooperatively revealed the synergistic strengthening of microelectronic polarization in Cs2CuBr4 PQDs induced by surface-frustrated Lewis pair-like properties and intrinsic Cu d-band properties facilitated robust CO2 adsorption and activation. This study demonstrated the potential of Cs2CuBr4 PQDs as a platform for highly efficient CO2 photoreduction and provided a distinct concept for CO2 adsorption and activation based on the catalytic mechanism of Cu-based PQDs.