CuInS2 ZnS Research Articles

3D-printed copolymer semi-cavity sensor with inner optical filter-effecting quantum dots photoluminescence for multiple drugs and amino acids detection

Here, we demonstrate a prototype for a novel optical sensor based on 3D-printed copolymer semi-cavity embedded with colloidal ZnCuInS (ZCIS) quantum dots (QDs) and utilizing the optical filter-effect in the QDs photoluminescence excitation pathway by analytes in the solution. First, in situ copolymerization of styrene and n-butyl methacrylate (P(S-BMA)) with colloidal ZCIS QDs allowed formation of solid P(S-BMA) matrix homogeneously impregnated with QDs. Then QDs@P(S-BMA) mixed with polylactic acid (PLA) has been processed into QDs@P(S-BMA)@PLA hybrid filaments using extruder. Then, a semi-cavity optical cell was 3D-printed out of QDs@P(S-BMA)@PLA filaments. Such 3D-printed semi-cavity cell can be used as the optical sensor on various molecules utilizing the optical absorption by analyte molecules through inner filter effect (IFE) of a properly selected QDs excitation beam. The multiple drug and amino acid molecules have been utilized having selective UV absorption to examine our proof of concept.

Anchoring gadolinium oxide nanoparticles onto CuInZnS: Efficient photocatalytic tetracycline degradation and mechanism analysis

Photocatalysis technology is one of the potential methods to remit the growing issues of environmental pollution. It is of great significance to rationally design high performance antibiotic wastewater degradation catalysts in the whole pH range. In this experiment, Gd2O3 nanoparticles (GdO NPs) were successfully grown onto CuInZnS (CIZS) by a simple hydrothermal method. The introduction of GdO has obvious effects on the nanosheet thickness of CIZS, which reduces carrier transport distances and improves the active sites number of CIZS. What’s more, the SO4•- absorption and electron transfer ability are also greatly optimized. Under 300 W Xe light, tetracycline can be efficient degraded more than 93 % in the whole pH range, which presents absolute advantage compared to CIZS and GdO. Based on the combination of experimental characterization and density functional theory calculations, the proposed photocatalytic tetracycline degradation pathway and mechanism have been given. Moreover, the results of toxicity analysis proved that the CIZS-GdO catalyst could successfully reduce the toxicity of tetracycline wastewater. This work has reference value for the application of rare earth oxides in the field of photocatalysis at full pH range.

Stimulated emission in a CuInS2/ZnS core-shell quantum-dot-doped liquid-core optical fiber.

We fabricated QD liquid-core optical fibers by doping C u I n S 2/Z n S (CIS/ZnS) core/shell QDs with cladding times of 90 and 60min, respectively, and compared and analyzed their emission properties with those of bare core C u I n S 2 QDs. For CIS/ZnS core/shell QDs (with cladding time of 90min) doped fibers, their emission transmits the longest distance in the fiber, and the emission intensity is approximately 4.73 times that of bare-core QD-doped fibers. Additionally, the fact that the full-width at half-maximum is narrowing and the spectral intensity is rapidly increasing superlinearly with excitation power indicates that stimulated emission happens in the fiber. The optical performance was compared and showed good agreement with a theoretical two-level system model for the QDs confined in an optical waveguide.

Unraveling the photocatalytic efficiency of quinary alloyed QDs for H2O2 production and antibiotic degradation with detail kinetic and influencing factor study

The optoelectronic properties of the quantum dots (QDs) have a significant effect on the photocatalytic efficiency. Presently, I−III−VI group QDs is becoming the conformist light harvesting resources in photocatalytic reactions. Herein, we have designed Cu-In-S (CIS) ternary QDs, ZnCuInS (ZCIS) quaternary, and quinary Zn-Cu-In-S-Se (ZCISSe) alloyed QDs by a cation-anion co-alloying approach. The optoelectronic properties of the prepared QDs, which includes bandgap energy, band-edge potentials, and charge carrier separation abilities can be handily tailored. Experimental outcomes revealed that, cation/anion co-doped quinary ZCISSe alloyed QDs can conquer a superlative equilibrium among light absorption ability, exciton separation-migration efficiencies in photocatalytic reactions in comparison to single cation doped ZCIS QDs. Thus, ZCISSe quinary QDs exhibits enhanced photocatalytic H2O2 production (2565.5 μmol. h−1. g−1) which is about 2 times higher than ZCIS and 8 times greater than CIS QDs with SCC of 0.36%. As well as the quinary QD shows a GMF degradation rate of 98.8% (k1–258×10−4 min−1) in 2 h of visible light illumination. Besides, this work is conferring a depth study by varying pH, scavengers, proton donors, and different environments of micropollutant degradation and O2 reduction, which promotes further expansion of effective multinary alloyed QDs, based photocatalytic materials.

Zn-Cu-In-Se quantum dots sensitized the etched and W-doped TiO2 nanoflowers with highly exposed {0 0 1} facets for superior photocatalytic performance

Herein, a high-performance composite photocatalyst was fabricated by using the three-dimensional TiO2 nanoflowers dominated by high-energy {001} facets as template and the emerging four-element Zn-Cu-In-Se (ZCISe) quantum dots (QDs) as sensitization material. The highly exposed high-energy {001} facets were more favorable for the adsorption reaction of organic pollutants, and which can form the unique surface heterojunctions to promote the charge transport. Before sensitizing ZCISe QDs, the surface characters and electronic structure of TiO2 nanoflowers were further optimized by a synchronous etching and W-doping treatment, thereby bringing in larger surface area, more active sites, proper impurity levels and increased electron density. Benefiting by the excellent surface properties, the ZCISe QDs were uniformly loaded on the surface of the etched and W-doped TiO2 (EWT) nanoflowers, and the high-quality TiO2/ZCISe heterojunctions with good interface connection were formed. In comparison to pure TiO2 nanoflowers, EWT@ZCISe composites exhibited significantly improved photocatalytic abilities for Rhodamine B (Rh B) under visible light. It was mainly related to the remarkable improvements in the light capture capability and the charge transport and separation characteristics. The optimal degradation rate of EWT@ZCISe composite for Rh B researched to 97.6% within 50 min, which is about 2.51 times higher than that of pure TiO2 nanoflowers. Additionally, the enhanced photocatalytic mechanism was also discussed in depth.

Performance Enhancement of Cadmium‐Free Quantum‐Dot Light‐Emitting Diodes via Cl‐Passivated Zn1−x−ySnxMgyO Nanoparticles as Electron Transport Layers

AbstractAlthough cadmium (Cd)‐based nanocrystals have enabled high‐performance quantum‐dot light‐emitting diodes (QLEDs), their mass production is likely to be affected by environmental protection policies. Among all the potential Cd‐free candidates, Cu‐In‐Zn‐S (CIZS) nanocrystals (NCs) have attracted particular interests. Still, the performance of the corresponding LED is currently limited by imbalanced charge injection and luminescence quenching, which are both related to the ZnO‐based electron transporting layer (ETL). This work demonstrates that ZnO nanoparticles (NPs) doped with Sn, Mg (Zn1−x−ySnxMgyO), and passivated with Cl are promising to resolve the above issues. All‐solution‐processed QLEDs based on Cd‐free CIZS NCs are fabricated by using Zn0.9Sn0.1O NPs as the ETL, and the peak external quantum efficiency (EQEmax) was nearly twice that of ZnO (EQEmax = 1.74%). The main reason is that the incorporation of Sn can reduce the conductivity of ZnO by an order of magnitude. Combining the advantages of Zn0.9Sn0.1O, Zn0.8Sn0.1Mg0.1O@Cl NPs are designed by the co‐doping of Mg and Cl passivation. The EQEmax and current efficiency based on Zn0.8Sn0.1Mg0.1O and Zn0.8Sn0.1Mg0.1O@Cl as ETLs are further increased to 4.84%, 14.00 cd A−1 and 5.53%, 15.99 cd A−1, respectively. The positive effects of Mg ions can remarkably optimize energy level structure to balance charge injection, while Cl can further passivate defects. The findings offer a new guideline for developing Cd‐free light‐emitting diodes.

Dye-induced photoluminescence quenching of quantum dots: role of excited state lifetime and confinement of charge carriers.

We investigate the role of quantum confinement and photoluminescence (PL) lifetime of photoexcited charge carriers in semiconductor core/shell quantum dots (QDs) via PL quenching due to surface modification. Surface modification is controlled by varying the number of dye molecules adsorbed onto the QD shell surface forming QD-dye nanoassemblies. We selected CuInS2/ZnS (CIS) and InP/ZnS (InP) core/shell QDs exhibiting relatively weak (664 meV) and strong (1194 meV) confinement potentials for the conduction band electron. Moreover, the difference in the emission mechanism gives rise to a long and short excited state lifetime of CIS (ca. 290 ns) and InP (ca. 37 ns) QDs. Dye molecules of different ionic characters (rhodamine 575: zwitterionic and rhodamine 560: cationic) are used as quenchers. A detailed analysis of Stern-Volmer data shows that (i) quenching is generally more pronounced in CIS-dye assemblies as compared to InP-dye assemblies, (ii) dynamic quenching is dominating in all QD-dye assemblies with only a minor contribution from static quenching and (iii) the cationic dye shows a stronger interaction with the QD shell surface than the zwitterionic dye. Observations (i) and (ii) can be explained by the differences in the amplitude of the electronic component of the exciton wavefunction near the dye binding sites in both QDs, which results in the breaking up of the electron-hole pair and favors charge trapping. Observation (iii) can be attributed to the variations in electrostatic interactions between the negatively charged QD shell surface and the cationic and zwitterionic dyes, with the former exhibiting a stronger interaction. Moreover, the long lifetime of CIS QDs facilitates us to easily probe different time scales of the trapping processes and thus differentiate the origins of static and dynamic quenching components that appear in the Stern-Volmer analysis.

Selective detection of aspartic acid in human serum by a fluorescent probe based on CuInS2@ZnS quantum dots

The importance of amino acids identification in biological systems has created expectation to develop a sensitive method for their detection. In this work, an efficient core-shell fluorescent quantum dots (QDs) probe based on CuInS2 (CIS) core and ZnS shell with the formula of CIS@ZnS QDs were synthesised and characterised by FT-IR, UV–Vis, TEM and DLS techniques. The probe was used for detection of Aspartic Acid (Asp) in an aqueous media. The probe shows a remarkable fluorescence response toward Asp over the other amino acids such as valine (Val), glycine (Gly), phenylalanine (Phe), leucine (Leu), alanine (Ala), serine (Ser), isoleucine (Iso), threonine (Thr), methionine (Met), Glutamic acid (Glu), histidine (His), arginine (Arg), cysteine (Cys), asparagine (Asn), glutamine (Gln), citrolline (Cit), sarcosine (Sar) and ornithine (Orn) the fluorescence intensity quenches significantly upon addition of Asp in an aqueous media. The CIS@ZnS QDs probe showed a selective and sensitive response by fluorescence quenching toward Asp in the concentration range of 8.3 × 10−7 M to 3.3 × 10−4 M with the detection limit of 7.8 × 10−8 M. The application of the sensor in determination of Asp in real human serum sample was also investigated. Based on our library search, the all reported fluorescent sensors for detection of Asp, either show a remarkable sensitivity to Glu acid. Luckily, this is the first presented optical probe able to detect just Asp from the solutions containing various amino acids.

Defect Control via Compositional Engineering of Zn-Cu-In-S Alloyed QDs for Photocatalytic H2O2 Generation and Micropollutant Degradation: Affecting Parameters, Kinetics, and Insightful Mechanism.

Photocatalytic H2O2 production and recalcitrant pollutant degradation are regarded as promising clean technology toward achieving sustainable solar-to-chemical energy conversion. Herein, nonstoichiometric Zn-Cu-In-S (ZCIS) quaternary alloyed quantum dots (QDs) are rationally fabricated via a reflux method toward H2O2 generation and ciprofloxacin degradation under visible light irradiation. The optimum catalyst (ZCIS-2) exhibits a notable H2O2 production of 1685.2 μmole h-1 g-1 (solar-to-chemical conversion efficiency (SCC), 0.19%), which is 5.3 times higher than that of CuInS2 (CIS), and a ciprofloxacin (CIP) degradation efficiency of 96% in 2 h. The observed improvement in activity corresponds to optimized exciton separation/transfer, broad photon absorption, tunable band alignment, and effective adsorption/activation. In addition, oxygen reduction goes through both direct two-electron single-step reduction and single-electron two-step superoxide radical pathways, whereas CIP degradation proceeds via direct •O2- and indirect •OH radical pathways, as confirmed by scavenger experiments. An appropriate amount of defects improves the adsorption/activation of O2 toward H2O2 and active oxygen species generation that facilitates CIP degradation. The effect of operational parameters, such as pH, surrounding environment, presence of ions, sacrificial agent, etc., on both H2O2 formation and CIP removal is vividly studied. Hence, the current study will provide an in-depth insight into O2 photoreduction and micropollutant removal, which encourages further advancement of potent alloyed quantum dot-oriented photocatalytic systems.

Zn-P bond induced S-scheme heterojunction for efficient photocatalytic tetracycline degradation synergistic H2 generation

A Zn-P bond oriented black phosphorus/CuInZnS S-scheme heterojunction was successfully constructed for tetracycline (TC) degradation and synergistic H2 generation. An enhanced photocatalytic H2 revolution rate of 2056.0 μmol/h/g was achieved with triethanolamine (TEOA) as the hole sacrifice agent, which was nearly two times higher than that of CuInZnS (CIZS) and 170 times that of black phosphorus (BP). To further improve the hole utilization rate and reduce the energy consumption, an appropriate amount of TC was added instead of TEOA, and an improved photocatalytic H2 generation rate of 1921.2 μmol/g was obtained with the synergistic degradation of TC by 82%. The types of heterojunctions and the transfer process of carriers were investigated by the combination of Mott-Schottky curves, Ultraviolet photoelectron spectroscopy, UV–vis diffuser reflectance spectra, and density functional theory. The results showed that a S-scheme heterojunction is built in BP/CIZS, which maintained the high redox ability of electron-hole pairs based on the successful separation of carriers. In addition, the novel Zn-P bond provided a charge transport channel and catalytic reaction active center upon photocatalysis. The design and application of photocatalysts proposed in this work offered a new idea for the coordinated resolution of environmental purification and energy conversion problems.

Glycol-assisted Cu-doped ZnS polyhedron-like structure as binder-free novel electrode materials

The facile, efficient, and straightforward preparation of electrode material for energy storage devices has drawn considerable interest for practical applications. In this study, we have synthesized the polyhedron Cu-doped ZnS (ZnS:Cu) structure on carbon cloth (CC) using a single-step glycol-assisted process. The highly interconnected polyhedron shaped ZnS:Cu functions as positive electrode material in an aqueous electrolyte for supercapacitor application. The ZnS:Cu polyhedron-like structures with higher electroactive sites and synergistic effect exhibited higher specific capacitance of 468 F g−1 at 1 Ag−1 and cycling stability of 890.5% after 5,000 cycles. The better electrochemical performance and higher cycling stability of ZnS:Cu can be dedicated to interconnected polyhedron-like structures, doping of Cu in ZnS, and binder-free electrode design. This underlines the potential of the Cu-doped ZnS-based supercapacitor for next-generation energy storage devices.

High efficiency polymer solar cells sensitized by red-emitting ZnCuInS nanoplatelets

We synthesized the two-dimensional Zn–Cu–In–S (ZCIS) semiconductor nanoplatelets and then modified their surface with 4-bromobenzenediazonium tetrafluoroborate. The surface modified ZCIS nanoplatelets were combined with the conventional photovoltaic hole transport layer material (HTL) PEDOT: PSS. The work function of the HTL increased from 5.04 eV to 5.17 eV, thus promoting the reduction of the energy potential barrier and increasing the internal electric field. It also effectively improves the light utilization by effectively increasing the absorption of light in the spectral range below 500 nm and converting them into the secondary emission in the 600–700 nm range. Such emission can be effectively utilized by the active layer to increase the open-circuit voltage (Voc) and short-circuit current (Jsc) of the cell, resulting in an increase in the overall cell power conversion efficiency (PCE) from 12.29%–13.14%.

Host-guest assemblies of anchoring molecular catalysts of CO2 reduction onto CuInS2/ZnS quantum dots for robust photocatalytic syngas production in water

Simultaneously fulfilling CO2-to-CO and 2H+-to-H2 reactions in water via photocatalyst represents an alternative to produce syngas driven by solar energy. To this end, photocatalyst having ability of simultaneously producing CO and H2 with controllable ratio should be exploited. In this work, we report a self-assembly photocatalyst C1@CD-CuInS2/ZnS quantum dots (QDs) that enabling to produce syngas robustly in CO2-saturated water under visible light irradiation. C1 is a molecular catalyst of linking an adamantine moiety to [Co(TPA)Cl]Cl (TPA = tris (2-pyridylmethyl) amine), while CD-CuInS2/ZnS QDs are semiconductor QDs with structure of CuInS2 core and ZnS shell and containing β-cyclodextrin (CD) on the surface. The C1@CD-CuInS2/ZnS QDs assemblies form by anchoring molecular cobalt catalyst C1 onto cyclodextrin (CD) modified CuInS2/ZnS quantum dots (CD-CuInS2/ZnS QDs) based on host-guest interaction between adamantine in C1 and cyclodextrin in the QDs. In which, C1 functions a molecular catalytic center mainly for CO2 reduction, and CD-CuInS2/ZnS QDs functions as both a light harvester and a hydrogen production center. The C1@CD-CuInS2/ZnS QDs system maintains syngas production activity over 200 h, and produces 184.21 μmol syngas with a CO/H2 ratio of 0.74 (ca. 2:3), exhibiting obvious advantages of syngas production efficiency in comparison to the non-assembled system and pristine CD-CuInS2/ZnS QDs system. Mechanism studies revealed that photoinduced electron transfer between CD-CuInS2/ZnS QDs and C1 occurs. The host-guest interaction improves syngas production activity and stability as well as plays positive role on stability of the molecular catalyst.

Selective and sensitive detection of Cu2+ ions in the midst of other metal ions using glutathione capped CuInS2/ZnS quantum dots

We herein report a facile fluorometric method for the detection of Cu 2+ ions by using water-soluble glutathione (GSH) capped ternary CuInS 2 /ZnS (CIS/ZnS) quantum dots (QDs). The as-synthesized QDs are ∼3.2 nm in diameter, nearly spherical in shape and fluorescent in the red region. Photostability studies revealed that the as-synthesized CuInS 2 /ZnS QDs maintained 70% of their initial fluorescence after hours of irradiation while the pH analysis showed that the QDs fluorescent emission was stable within the pH 4–11 with maximum stability at pH 6. The fluorometric analysis revealed that the QDs undergoes remarkable photoluminescence quenching in the presence of Cu 2+ ions compared to other metal ions such as Hg 2+ , Co 2+ , Cd 2+ , Pb 2+ , Zn 2+ , Ni 2+ , Mg 2+ , Sn 2+ , Mn 2+ , Fe 2+ , Fe 3+ ions. The Fourier transform infra-red (FTIR) spectroscopy, Dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses revealed that the quenching could be attributed to the aggregation of QDs due to the complexation of Cu 2+ ions with the GSH capping group of the QDs. The fluorescence quenching of CIS/ZnS QDs exhibited linear response against Cu 2+ ions in the concentration range of 75–750 nM with a detection limit of 63 nM. These results reveled that GSH capped CIS/ZnS QD sensor could be a potential fluorescent probe for the detection of Cu 2+ ions in aqueous solutions .

Synthesis and Optical Properties of In2S3-Hosted Colloidal Zn-Cu-In-S Nanoplatelets.

High-efficiency photoluminescence quaternary hexagon Zn–Cu–In–S (ZCIS) nanoplatelets (NPls) have been synthesized by a two-step cation exchange method, which starts with the In2S3 NPls followed by the addition of Cu and Zn. It is the first time that In2S3 NPls are used as templates to synthesize ZCIS NPls. In this paper, the reaction temperature of In2S3 is essential for the formation of NPls. The photoluminescence wavelength of NPls can be tuned by adjusting the temperature of Cu addition. To enhance the stability of the resulting NPls and to improve their optical properties, we introduced Zn2+ and obtained ZCIS NPls by cation exchange on the surface. It is worth noting that the obtained ZCIS NPls show a shorter fluorescence lifetime than other ternary copper sulfide-based NPls. This work provides a new way to synthesize high-efficiency, nontoxic, and no byproduct ZCIS NPls.

Synergistic combination of TiO2-sol interconnecting-modified photoanode with alginate hydrogel-assisted electrolyte for quantum dots sensitized solar cells

Constructing the highly efficient and stable quasi-solid-state even solid-state devices is one of the most significant tendency in the field of quantum dots sensitized solar cells (QDSCs). Herein, highly efficient and stable quasi-solid-state (QS)-QDSCs devices were fabricated via synergistically combining the TiO2-sol interconnecting-modified photoanodes with alginate hydrogel (AH)-assisted electrolyte films. TiO2-sol binding agent could incorporate into the surface and voids of TiO2 particles, which increased the surface area and roughness for QDs loading and induced better connection between the neighboring particles. Meanwhile, the AH-assisted QS-electrolyte films possessed the crosslinking hydrogel network structure and exhibited the perfect interfacial contact with the modified TiO2 surface, thus enhancing the ion transport and redox reaction of polysulfide couple. Benefited from the synergistic effect of TiO2-sol modified photoanodes and alginate hydrogel (AH)-assisted electrolytes, a champion power conversion efficiency (PCE) of 8.87% for model ZnCuInSe (ZCISe) based QS-QDSCs was achieved with an enhancement of near 10% related to that of the devices based the pristine devices (8.01%), and very close to that of liquid-junction QDSCs (9.06%). Moreover, the constructed QS-QDSCs devices exhibit the excellent stability. This work thus provides a facile and effective strategy to achieve the QS-QDSCs devices with both of high efficiency and good stability.

Emission and Decay Lifetime Tunability in Less-Toxic Quaternary ZnCuInS Quantum Dots

Due to the increasing need for the use of safer nanomaterials in the electronic and optoelectronic sectors, there is a growing emphasis on the development of less-toxic quantum dots (QD) as replacements for traditional cadmium or lead-based QD technologies. Although the ternary Cu-In-S (CIS) QDs have gained prominence due to their advantageous optical properties and unique tunability, their intrinsically defective structures present some drawbacks for device applications. A one-pot, high-throughput process was developed to synthesize quaternary Zn-Cu-In-S (ZCIS) QDs, which show higher structural crystallinity and lattice stability. Stoichiometric variation was explored to determine its impact on QD optical and structural properties. It was found that the trial-cationic structure of the quaternary ZCIS QDs allowed further variation and flexibility of QD properties. Induction of Cu deficiency via In- or Zn-excess precursor ratios improved photoluminescence (PL) intensity and structural stability. ZnS overcoating was investigated, but it was found that the Zn-containing ZCIS cores, which are more stable than core CIS QDs, benefitted only minimally from Zn-passivation. The highly emissive quaternary QDs produced through this scalable synthesis procedure are widely tunable and functionalizable, capable of emission from 564-650 nm, and with a high lifetime up to 159 ns, making them more suitable for a variety of device applications.

High-performance tricolored white lighting electroluminescent devices integrated with environmentally benign quantum dots.

The electroluminescent (EL) performances of quantum dot-light-emitting diodes (QLEDs) based on either high-quality CdSe- or Cd-free quantum dots (QDs) have been greatly improved during the last decade, exclusively aiming at monochromatic devices for display applications. Meanwhile, work on white lighting QLEDs integrated particularly with Cd-free QDs remains highly underdeveloped. In this work, the solution-processed fabrication of tricolored white lighting QLEDs comprising three environmentally benign primary color emitters of II-VI blue and green ZnSeTe and I-III-VI red Zn-Cu-In-S (ZCIS) QDs is explored. The emitting layer (EML) consists of two different QD layers stacked on top of the other with an ultrathin ZnMgO nanoparticle buffer layer inserted in the middle, with both blue and green QDs mixed in one layer, and red QDs placed in a separate layer. The stacking order of the bilayered EML architecture is found to control the exciton recombination zone and thus crucially determine the EL performance of the device. The optimal tricolored white device yields outstanding EL performances such as 5461 cd m-2 luminance, 5.8% external quantum efficiency, and 8.4 lm W-1 power efficiency, along with a near-ideal color rendering index of 95, corresponding to the record quantities reported among Cd-free white lighting QLEDs.

Improving the Performance of Near-infrared CuInSe2 Quantum Dots by Two Strategies: Doping and Ligand Exchange

Oil phase CuInSe2 quantum dots (CISe QDs) were synthesized via a hot-injection method, exhibiting a near-infrared (NIR) emission wavelength of 710[Formula: see text]nm with poor fluorescence intensity. Therefore, we address this challenge by introducing two strategies: doping and ligand exchange. First, Zn was used as a dopant to improve the fluorescent properties of CISe QDs synthesized by the same method. The PL peak position of the resulting Zn–CuInSe (ZnCISe) QDs could be tuned from 600[Formula: see text]nm to 662[Formula: see text]nm, and the PL intensity of the QDs was greatly improved. Except that, this Zn doping strategy can help to improve the fluorescence lifetime and reduce defects, leading to increased quantum yield. Next, the aqueous phase transfer of ZnCISe QDs was achieved through an efficient ligand exchange strategy using glutathione (GSH) as the bifunctional ligand. Mercaptoacetic acid (MPA) was also used as an essential additive for GSH ligand exchange. With this method, we obtained high-quality hydrophilic ZnCISe QDs with particle sizes less than 3[Formula: see text]nm and good monodispersity. In addition, DLS measurements showed a unimodal peak shape of the hydrated ZnCISe QDs in ultrapure water with particle sizes ranging from 7[Formula: see text]nm to 40[Formula: see text]nm. Finally, the cytotoxicity studies revealed that the viabilities of the cells incubated with ZnCISe QDs from 1[Formula: see text][Formula: see text]g/mL to 18[Formula: see text][Formula: see text]g/mL remained at levels greater than 90%, which indicates that QDs with good biocompatibility are promising fluorescent probes.

Facile synthesis of Cu-In-Zn-S alloy nanospheres for fast photoelectric detection across the visible spectrum

Fast and broadband photoelectric detection is a key process to many photoelectronic applications, during which the semiconductor light absorber plays a critical role. In this report, we prepared Cu-In-Zn-S (CIZS) nanospheres with different compositions via a facile hydrothermal method. These nanospheres were ~200 nm in size and comprised of many small nanocrystals. A photodetector responded to the visible spectrum was demonstrated by spraying the solution processed nanospheres onto gold interdigital electrodes. The photoelectric characterization of these devices revealed that CIZS nanospheres with low molar ratio of n(Cu)/n(In) exhibited improved photoelectric response compared to those with high n(Cu)/n(In), which was attributed to the reduced defects. The relatively large switching ratio (Ion/Ioff), fast response and wide spectral coverage of the CIZS-based photodetector render it a promising potential candidate for photoelectronic applications.