SnS Quantum Dots Research Articles

SnS Quantum Dots Enhancing Carbon-Based Hole Transport Layer-Free Visible Photodetectors.

The recombination of charges and thermal excitation of carriers at the interface between methylammonium lead iodide perovskite (PVK) and the carbon electrode are crucial factors that affect the optoelectronic performance of carbon-based hole transport layer (HTL)-free perovskite photodetectors. In this work, a method was employed to introduce SnS quantum dots (QDs) on the back surface of perovskite, which passivated the defect states on the back surface of perovskite and addressed the energy-level mismatch issue between perovskite and carbon electrode. Performance testing of the QDs and the photodetector revealed that SnS QDs possess energy-level structures that are well matched with perovskite and have high absorption coefficients. The incorporation of these QDs into the interface layer effectively suppresses the dark current of the photodetector and greatly enhances the utilization of incident light. The experimental results demonstrate that the introduction of SnS QDs reduces the dark current by an order of magnitude compared to the pristine device at 0 V bias and increases the responsivity by 10%. The optimized photodetector exhibits a wide spectral response range (350 nm to 750 nm), high responsivity (0.32 A/W at 500 nm), and high specific detectivity (>1 × 1012 Jones).

A robust bio-source mediated CeO2 – SnS2 quantum dots @Oryza sativa var. biochar, photo-adsorbent for removal of Baszol Violet 57L dye from aqueous discharge: Development, materialistic analyses, and its application

This research aims to develop an entirely novel kind of photocatalytic adsorbent, known as integrated photocatalytic adsorbent, using a hydrothermal process that is environmentally friendly. This method utilizes an extract derived from Tulsi (Osmium Tenuiflorum) leaves as a stabilizing and capping agent. The purpose of the synthesized material is to effectively remove Baszol Violet 57L (BV57L) dye from wastewater. CeO2, was combined with a semiconductor photocatalyst, SnS2, to create a composite photocatalyst. This choice was made based on the exceptional photocatalytic activity of the catalyst when supported on rice straw (Oryza sativa var.) biochar, specifically for the adsorption of selected pollutants. The study investigated the integrated photocatalytic and adsorption (IPA) characteristics of the fabricated material, using BV57L dye as a representative emerging pollutant commonly found in wastewater. From the Tauc's plots of final nanohybrid (CSB) it was calculated that the energy band gap of CSB was around ∼2.7 eV. The novelty of the current study lies in its examination of the synergistic adsorption and photocatalytic properties under diverse reaction conditions that replicate real-world wastewater conditions. The inclusion of biochar in the CeO2-SnS2 nanocomposite yielded a discernible decline in the rate of charge recombination, thereby causing a notable enhancement in the photocatalytic efficiency of the nanocomposite.The adsorption data confirmed with the Langmuir isotherm model with maximum adsorption capacity of 333.58 mg g−1 at BV57L concentration of 350 mg L−1 under optimal conditions, suggesting the occurrence of monolayer chemosorption and following pseudo-second-order rate kinetics with rate constant of 1.59 × 10−5 g mg−1 min−1. The process of photodegradation exhibits kinetics that can be approximated as pseudo-first-order, with the BV57L dye displaying a significant constant of 0.0731 min−1. A simultaneously processed adsorption and photodegradation model was found to achieve an overall BV57L removal efficiency of 97.26 % within a 90-min timeframe. Additionally, impact of pH, reusability-stability of catalyst, and a photodegradation mechanism for the BV57L removal is also clearly presented. The combination of visible light-induced photodegradation activity in CeO2-SnS2 nanocomposite and the adsorption capability of biochar leads to the highly effective removal of pollutants from the liquid phase.

Sonochemical synthesis of SnS and SnS2 quantum dots from aqueous solutions, and their photo- and sonocatalytic activity

Our study reports the ultrasound-assisted synthesis of SnS and SnS2 in the form of nanoparticles using aqueous solutions of respective tin chloride and thioacetamide varying sonication time. The presence of both compounds is confirmed by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, as well as Raman and FT-IR spectroscopic techniques. The existence of nanoparticles is proven by powder X-ray diffraction investigation and by high resolution transmission electron microscopy observations. The size of nanocrystallites are in the range of 3–8 nm and 30 50 nm for SnS, and 1.5–10 nm for SnS2. X-ray photoelectron spectroscopy measurements, used to investigate the chemical state of tin and sulphur atoms on the surface of nanoparticles, reveal that they are typically covered with tin on the same oxidation degree as respective bulk compound. Values of optical bandgaps of synthesized nanoparticles, according to the Tauc method, were 2.31, 1.47 and 1.05 eV for SnS (60, 90 and 120 min long synthesis, respectively), and 2.81, 2.78 and 2.70 eV for SnS2 (60, 90 and 120 min long synthesis, respectively). Obtained nanoparticles were utilized as photo- and sonocatalysts in the process of degradation of model azo-dye molecules by UV-C light or ultrasound. Quantum dots of SnS2 obtained under sonication lasting 120 min were the best photocatalyst (66.9 % color removal), while quantum dots of SnS obtained under similar sonication time were the best sonocatalyst (85.2 % color removal).

High-performance flexible resistive random-access memory based on SnS2 quantum dots with a charge trapping/de-trapping effect.

The application of resistive random-access memory (RRAM) in storage and neuromorphic computing has attracted widespread attention. Benefitting from the quantum effect, transition metal dichalcogenides (TMD) quantum dots (QDs) exhibit distinctive optical and electronic properties, which make them promising candidates for emerging RRAM. Here, we show a high-performance forming-free flexible RRAM based on high-quality tin disulfide (SnS2) QDs prepared by a facile liquid phase method. The RRAM device demonstrates high flexibility with a large on/off ratio of ∼106 and a long retention time of over 3 × 104 s. The excellent switching behavior of the memristor is elucidated by a charge trapping/de-trapping mechanism where the SnS2 QDs act as charge trapping centers. This study is of significance for the understanding and development of TMD QD-based flexible memristors.

SnS2 quantum dots-coated VO2@carbon nanorods for secondary battery displaying high capacity and rate-performance.

Electrode materials optimization is one of the keys to improving the energy storage characteristics of secondary batteries. Herein, a VO2@carbon@SnS2 composite is developed by coating SnS2 quantum dots (QDs) on lamellar VO2@carbon nanorods, yielding a high-performance aluminum-ion battery cathode. SnS2 QDs embedded in VO2@carbon accelerate electron transport, while the in situ coating of carbon improves cycling stability. When cycling at 0.5 A g-1, capacity is maintained at 157.6 mA h g-1 after 200 cycles. Even at 1.0 A g-1, the cathode can be stably cycled 1000 times. Capacity remains at 176.3 mA h g-1 and coulombic efficiency is 99.1% at temperatures below -10 °C after 100 cycles. These findings provide new ideas for the development of QD-modified composites for application in secondary batteries.

One-step hydrothermal synthesis of Cu doped SnS2 quantum dots anchored on reduced graphene oxide (rGO) as high-performance electrodes for supercapacitors

Cu doped SnS2/rGO composites are prepared by a one-step hydrothermal method. The obtained Cu doped SnS2/rGO composite shows a ultrathin lamellar structure, with quantum dots of SnS2 anchored on reduced graphene oxide (rGO). According to the testing results from the three-electrode system indicate that the successful doping of Cu and the presence of rGO improve the electrochemical performance of SnS2. The Cu doped SnS2/rGO composite exhibits a high specific capacitance of 387.27 F g−1 at 1 A g−1, which is almost seven times of that of pure SnS2. It also performs well in cycling stability tests (95.2 % after 2000 cycles). The asymmetric supercapacitor also shows impressive energy and power densities. The excellent electrochemical performance reveals its potential application as a supercapacitor electrode material.

AuPt Nanodonuts as a Novel Coreaction Accelerator and Luminophore for a Label-free Electrochemiluminescence Aptasensor.

Novel and effective coreaction accelerators are of great importance in electrochemiluminescence (ECL) systems. In this work, novel AuPt nanodonuts, i.e., SnS2 quantum dots (QDs)/Cys-AuPt heterogeneous nanorings (NRs), serve as both a highly effective coreaction accelerator and the luminophore in a label-free ECL aptasensor. The novel AuPt nanodonuts were formed by decorating SnS2 QDs onto AuPt NR surfaces, which would promote the production of more coreactant intermediate in the SnS2 QDs/K2S2O8 system. As a result, the ECL performance was greatly improved. Meanwhile, l-cysteine (l-Cys) played an important role in the combination between AuPt NRs and SnS2 QDs, and the nanodonuts served as the matrix to load numerous lincomycin (Lin) aptamers. Under optimal conditions, the ECL aptasensor exhibited ultrasensitive detection of Lin from 1 to 0.1 pg/mL with a limit of detection (LOD) of 0.7 fg/mL (1.72 fM)..

Defect-mediated saturable absorption and carrier dynamics in tin (II) monosulfide quantum dots.

Tin (II) monosulfide (SnS) has attracted considerable attention in emerging photonics and optoelectronics because of high carrier mobility, large absorption coefficient, anisotropic linear and nonlinear optical properties, and long-time stability. In this Letter, we report third-order nonlinear absorption and refraction of SnS quantum dots (QDs). Under excitation with 800-nm femtosecond pulses, QDs exhibit saturable absorption (saturation intensity ∼ 47.69 GW/cm2) and positive refractive nonlinearity (nonlinear refraction coefficient ∼ 1.24 × 10-15 cm2/W). Nonetheless, we investigate charge carrier dynamics using femtosecond transient absorption spectroscopy and propose the presence of midgap defect states which not only dictate carrier dynamics but also give rise to nonlinear optical properties in SnS QDs.

Single-atom Ce targeted regulation SnS/SnS2 heterojunction for sensitive and stable room-temperature ppb-level gas sensor

Metal sulfide-based gas sensors have the advantage of high sensitivity at room temperature, enabling high integration and low power consumption. However, a trade-off between low baseline resistance and good long-term stability at room temperature still needs to be addressed. Therefore, a single-atom Ce-targeted regulation strategy for p-SnS/n-SnS2 was proposed. By doping different amounts of Ce, the amount and size of SnS quantum dots on the surface of SnS2 can be regulated. Furthermore, Sn-S-Ce bonds are formed by combining single-atom Ce with SnS, which effectively hinders the growth and oxidation of SnS quantum dots, as evidenced by STEM, XPS, DFT, FTIR and EAXFS methods. Due to the unique energy band structure of p-SnS and n-SnS2, Ce-doped SnS quantum dots serve as electronic sensitizers, effectively increasing the carrier concentration in SnS2. The optimal gas sensor based on the 1% Ce-doped SnS/SnS2 composites enables high sensitivity (with a response of 22.1 to 1 ppm NO2), ultralow detection limit (1 ppb), excellent long-term stability at room temperature, and a lower baseline resistance. This engineering strategy of metal sulfide semiconductor heterostructures through single-atom targeted regulation provides new insights for further optimizing the composite system.

Self-assembled ZnIn2S4/SnS2 QDs S-scheme heterojunction for boosted photocatalytic hydrogen evolution: Energy band engineering and mechanism insight

Rapid and efficient transfer and separation of photo-induced carriers are critical for designing environmentally friendly and efficient photocatalysts in catalytic hydrogen evolution. Here, we design a 0D/2D S-scheme heterojunction involving ZnIn2S4 (ZIS) nanosheets self-assembled with SnS2 quantum dots (QDs). The formation of the S-scheme ZIS/SnS2 QDs heterojunction is demonstrated by experimental characteristics and density functional theory (DFT) analyzes, which greatly promotes charge transfer and transport under the interfacial electric field (IEF), lengthens carrier lifetime, enhances light-harvesting properties, and significantly decreases the Gibbs free energy during the catalysis reaction. Therefore, the optimized ZIS/SnS2 photocatalyst achieves a high hydrogen production rate of 1.13 mmol g−1 h−1, which is 16.14 folds the one of pure ZIS. This study provides novel perspectives into the reasonable design of S-scheme photocatalyst by virtue of the theories of energy band engineering and IEF adjustment.

Lithium Azides Induced SnS Quantum Dots for Ultra-Fast and Long-Term Sodium Storage.

Tin sulfide (SnS) is an attractive anode for sodium ion batteries (NIBs) because of its high theoretical capacity, while it seriously suffers from the inherently poor conductivity and huge volume variation during the cycling process, leading to inferior lifespan. To intrinsically maximize the sodium storage of SnS, herein, lithium azides (LiN3 )-induced SnS quantum dots (QDs) are first reported using a simple electrospinning strategy, where SnS QDs are uniformly distributed in the carbon fibers. Taking the advantage of LiN3 , which can effectively prevent the growth of crystal nuclei during the thermal treatment, the well-dispersed SnS QDs performs superior Na+ transfer kinetics and pseudocapacitive when used as an anode material for NIBs. The 3D SnS quantum dots embedded uniformly in N-doped nanofibers (SnS QDs@NCF) electrodes display superior long cycling life-span (484.6mAhg-1 after 5800 cycles at 2Ag-1 and 430.9mAhg-1 after 7880 cycles at 10Ag-1 ), as well as excellent rate capability (422.3mAhg-1 at 20Ag-1 ). This fabrication of transition metal sulfides QDs composites provide a feasible strategy to develop NIBs with long life-span and superior rate capability to pave its practical implementation.

Highly efficient near-infrared electrochemiluminescence resonance energy transfer system for biosensing: Nonmetallic plasmon Mediated well-matched energy donor-acceptor pair

Herein, a well-matched energy donor-acceptor pair strategy was designed to construct highly efficient NIR ECL-RET system. In detail, an ECL amplification system consisting of SnS2 quantum dots decorated Ti3C2 MXene nanocomposites (SnS2 QDs-Ti3C2) as the energy donor were developed via a one-pot method, and the nanocomposites exhibited highly efficient NIR ECL emission due to the surface-defect effect generated by the oxygen-containing functional groups in MXene. Nonmetallic plasmon hydrated defective tungsten oxide nanosheets (dWO3•H2O) were utilized as energy acceptors because of its strong surface plasmon resonance effect in Vis-NIR absorption range. Compared with non-defective tungsten oxide hydrate nanosheets (WO3•H2O), the overlapping area between ECL spectrum of SnS2 QDs-Ti3C2 and UV–vis spectrum of dWO3•H2O was increased by 2.1 times, and the results showed that more efficient quenching effect was obtained. As a proof of concept, tetracycline (TCN) aptamer and its complementary chain were served as a bridge to connect the energy donor and acceptor, achieving the successful construction of NIR ECL-RET aptasensor. The as-fabricated ECL sensing platform exhibited a low detection limit of 6.2 fM (S/N = 3) within a wide linear range from 10 fM to 10 μM. Besides, the NIR ECL-RET aptasensor also showed excellent stability, reproducibility and selectivity, providing a promising tool to detect TCN in real samples. This strategy offered a universal and effective method in constructing highly efficient NIR ECL-RET system for developing rapid, sensitive and accurate biological detection platform.

Improved Charge Transfer for NO2 Gas Sensors by Using 0D SnS Quantum Dot/2D WSe2 Heterostructures

A highly sensitive array of two-dimensional (2D) WSe2 nanosheets integrated with zero-dimensional (0D) SnS quantum dots was synthesized by combining liquid-phase exfoliation and wet chemical synthesis methods. The characterization results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) revealed the formation of WSe2/SnS heterostructures, which enable a cyclic and reproducible high gas sensing response. The role allocation of SnS on WSe2 was verified by using density functional theory (DFT) calculations. The result indicates that the top alignment of SnS and the bottom layer of WSe2 act as a gas adsorption layer and carrier conduction layer, respectively. The charge interactions of the heterostructures were systematically explored by monitoring changes in the transferred characteristics at room temperature (27 °C) after introducing 25–100 ppb NO2. The highest sensing response of WSe2/SnS heterostructures toward the NO2 gas was found to be 1.08 at 25 ppb with a LOD of 10.6 ppb. The experimental and simulation results revealed that the charge transfer across the active sites increased after incorporating SnS in the WSe2. The sensing results showed an abrupt and reliable gas response under periodic NO2 gas injection unambiguously achieved by such heterostructures. The sensor also exhibited satisfactory stability and accuracy in selectivity and is not affected by humidity at room temperature. DFT calculations were also used to explain the sensing mechanism and heterojunction for such nanocomposites.

Rationally incorporated SnO2/SnS2 nanoparticles on sulfur-doped graphene aerogels for high-performance lithium/sodium-ion batteries

Tin-based anode materials, such as tin oxide and tin sulfide, have received increased attention due to their high theoretical capacity, natural abundance, and adequate operating voltage. But the large volume variation and sluggish reaction kinetics lead to severe structural deterioration and capacity fading during the charge-discharge process, hindering their practical application. Herein, we synthesized a unique ternary hybrid structure to grow SnS2 nanosheets and SnO2 particles on graphene aerogels by hydrothermal method (denoted as SnO2/SnS2/SGA). The SnO2/SnS2/SGA exhibited better cycling stability than SnS2/GA and SnO2/GA. The tight adhesion of SnO2/SnS2 helps to alleviate the undesired electrode materials destruction due to volume expansion. Furthermore, SnO2 and SnS2 quantum dots anchored on graphene aerogels can undergo reversible conversion reaction that profit by synergistic effect. The reversibility of the SnO2/SnS2/SGA material during the transition was also proved by ex-situ high-resolution transmission electron microscopy. The SnO2/SnS2/SGA hybrid was endowed with enhanced electrochemical capability.

Achieving High Responsivity and Detectivity in a Quantum-Dot-in-Perovskite Photodetector.

This work reports on quantum dots (QDs) in perovskite photodetectors showing high optoelectronic performance via quantum-dot-assisted charge transmission. The self-powered broad-band photodetector constructed with SnS QDs in FAPb0.5Sn0.5I3 perovskite can capture incoming optical signals directly at zero bias. The QDs-in-perovskite photodetector exhibits a high sensitivity in the wavelength range from 300 to 1000 nm. Its responsivity at 850 nm reaches 521.7 mA W-1, and a high specific detectivity of 2.57 × 1012 jones can be achieved, which is well beyond the level of previous self-powered broad-band photodetectors. The capability of quantum-dot-in-perovskite photodetectors as data receivers has been further demonstrated in a visible-light communication application.

Green and environmentally sustainable fabrication of SnS2 quantum dots/chitosan nanocomposite for enhanced photocatalytic performance: Effect of process variables, and water matrices.

Concerns over the availability of clean water and the quality of treated wastewater are significant problems that call for an appropriate solution to improve the water quality. The present work emphasized the synthesis of novel SnS2 quantum dots (QDs) deposited on chitosan via a facile green precipitation method involving neem (Azadirachta indica) leaf extract and investigating its photocatalytic performance for the degradation of Crystal violet (CV) dye under varying reaction parameters, other organic and inorganic salts and water matrices. The crystal structure, surface morphology, and elemental composition of the prepared SnS2 (QDs)/Ch composite were evaluated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and energy dispersive X-ray analysis (EDAX) techniques. The average size of SnS2/Chitosan nanoparticles was calculated to be 8.8nm using XRD, with the average diameter of SnS2 QDs to be 3.3nm from TEM. UV-visible spectroscopy was used to investigate its optical properties. The direct band gap of SnS2/Chitosan estimated from Tauc's plot came to be 2.5eV. The prepared novel SnS2/Ch composite showed outstanding photocatalytic activity for the degradation of CV through the Advanced Oxidation Process (AOP). The fabricated photocatalyst caused 98.60±1.34 % degradation of CV within a short period of 70min under optimum conditions. The photodegradation reaction followed pseudo-first-order rate kinetics with a rate constant of 0.0815min-1. Furthermore, the photocatalyst showed high stability and was reusable for up to four cycles. The present work fulfils the aim of designing a novel, green, and efficient visible light-active nano-photocatalyst.

SnS2 Quantum Dots Decorated MoS2 Nanosheets Enabling Efficient Photocatalytic H2 Evolution in CO2 Saturated Water

SnS2 Quantum Dots Decorated MoS2 Nanosheets Enabling Efficient Photocatalytic H2 Evolution in CO2 Saturated Water

Construction of Direct Z-Scheme SnS2 Quantum Dots/Conjugated Polyimide with Superior Photocarrier Separation for Enhanced Photocatalytic Performances.

In this study, a novel direct Z-scheme SnS2 quantum dots/sulfur-doped polyimide (SQDs/SPI) photocatalyst was firstly fabricated by an in situ crystallization growth of SnS2 quantum dots on sulfur-doped polyimide through a facile hydrothermal method. The photocatalytic hydrogen production activity of 5SQDs/SPI samples reached 3526 μmoL g-1 in the coexistence of triethanolamine and methanol used as hole sacrificial agents, which is about 13 times higher than that of SPI under the same conditions and 42 times higher than that of SPI only as a hole sacrificial agent. The improvement can be related to the direct Z-scheme charge transfer in the tight interface between SQDs and SPI, which promoted rapid separation and significantly prolonged the lifetime of photoexcited carriers. The Z-scheme charge transfer mechanism was proposed. This discovery comes up with a new strategy for the development of an efficient, environmentally friendly, and sustainable sulfide quantum dots/polymer non-noble metal photocatalyst.

Assembling inner filter effect reduced SnS2 quantum dots-based hollow polymeric spherical nanoshells for ratio electrochemiluminescence bioassay

SnS2 quantum dots (QDs) as excellent electrochemiluminescence (ECL) luminators have exhibited a good application prospect in ECL field, but the difficulty of being effectively immobilized on the electrode and inner filter effect caused by their compact packaging make the construction of SnS2 QDs-based ECL system challenging. This work developed a hollow polymeric spherical nanoshells (HPSNs) for loading SnS2 QDs. SiO2 nanoparticles (NPs) served as the carrier for the multilayer assembly of polyethyleneimine (PEI)-SnS2 QDs and polyacrylic acid (PAA). Then, SiO2 NPs were etched to produce SnS2 QDs-based HPSNs (SnS2-HPSNs), which can not only achieve the high loading of SnS2 QDs but effectively reduce their inner filter effect, revealing a significantly improved cathodic ECL performance. SnS2-HPSNs coupled with anodic luminators Ir nanorods (NRs) to construct a ratiometric ECL biosensor for detecting cardiac troponin I (cTnI) with tripropylamine (TPrA) and persulfate (S2O82-) as anodic and cathodic co-reactants, respectively. Norepinephrine (NE) and gold nanoparticles (AuNPs) were innovatively developed as dual-quencher for Ir NRs. The secondary antibody complex containing SnS2-HPSNs and NE-AuNPs was specially constructed and its assembly on the biosensor modified with Ir NRs can conveniently realize the different changes of the two signals, thus achieving the sensitive detection of cTnI with a detection limit of 0.32 pg/mL. The HPSNs provided an effective strategy for high loading of QDs while reducing their inner filter effect. The integration of two luminators (SnS2-HPSNs and Ir NRs) and dual-quencher created a promising ECL ratio platform for the accurate detection of various biomarkers.

Controlled Synthesis of Europium-Doped SnS Quantum Dots for Ultra-Fast Degradation of Selective Industrial Dyes

Herein, SnS and Eu-doped SnS QDs have been synthesized by a facile chemical co-precipitation method for efficient photocatalytic degradation of organic dye molecules. The structural, morphological, and optical properties of QDs were investigated by various physiochemical characterization techniques. The photocatalytic degradation of methylene blue (MB) and crystal violet (CV) dyes have been studied under visible light irradiation under direct sunlight using a spectrophotometer. Enhanced photodegradation efficiency of 87% and 94% were attained for SnS and Eu (4%)-doped SnS, respectively. For CV dye, the pure SnS showed only 70.7% however the Eu (4%)-doped SnS achieved 99% efficiency. The rate constant value of the doped SnS was found to be much higher than that of pure SnS for both dyes. The obtained results from various characterization studies provided the reason for the enhancement of the photocatalytic activity of Eu-doped SnS QDs due to the presence of Eu3+ in the SnS lattice, and also smaller crystallite size with high surface area and its morphological features. Moreover, the Eu3+ plays an essential role in reducing the band gap, hampering recombination, and the generation of free radicals, thus the QDs promoted attractive degradation activity and high stability.