SnSe Nanosheets Research Articles

Controlled Growth of Two-Dimensional SnSe/SnS Core/Crown Heterostructures.

We present a novel, straightforward, and reproducible one-pot heating up technique to synthesize core/crown SnSe/SnS nanosheets by a careful adjustment of the sulfur and selenium precursor reactivity. Here, the SnSe nanosheets are prepared via a wet-chemical route using SnCl2 and selenium phosphines. By adding a highly reactive S-oleylamine complex during the growth of the SnSe sheets at 240 °C, SnS crowns were formed within the SnSe sheets. The number of SnS crowns can be tailored upon repeated addition of S-oleylamine. A combination of transmission electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy proves the formation of highly crystalline core/crown structures.

Self-biased photoelectrochemical photodetector based on liquid phase exfoliated SnSe nanosheets

The present article involves a liquid phase exfoliation technique to synthesize SnSe nanosheets. These nanosheets are deposited on an ITO glass substrate to make a thin film via an electrophoretic deposition (EPD) technique. Through the use of energy-dispersive X-ray analysis (EDAX), the cleanliness and chemical compositions of the film are examined. The surface topography of the deposited film is carried out by scanning electron microscopy (SEM). The orthorhombic crystal structure of SnSe thin film is verified by X-ray diffraction (XRD) analysis. The optical gap energy and absorbance profiles also exhibit a morphology-dependent response, as measured by ultraviolet–visible (UV–vis) spectroscopy. The Photoresponse performance of SnSe thin film-based PEC-type photodetector was carried out under illumination of poly and monochromatic wavelengths. SnSe nanosheet-based photodetector showed a maximum photocurrent of 14.50 μA under polychromatic light of intensity 100 mW/cm2, at zero bias. This study demonstrates how the Requirement for TMC semiconductors in optoelectronic devices increases due to their exceptional photoresponse performance.

Boosted Near-Infrared Photothermal Conversion in Rare Earth Ions-Doped 2D SnSe Nanosheets for Solar-Powered Water Evaporation Systems.

Solar-powered water evaporation as a clean and abundant renewable energy-efficient desalination technology provides a promising strategy to solve the shortage of freshwater resources. However, the development and application of solar vapor technology are hindered by the relatively low near-infrared photothermal conversion efficiency of existing materials and the lack of effective improvement strategies. In this work, the conductivity characteristics of 2Dsemiconductors are capitalized on the high visible light absorption and ultra-low thermal. Specifically, rare-earth ion dopants into SnSe nanosheets, significantly boosting their near-infrared photothermal conversion efficiency and solar water evaporation performance are introduced. Remarkably, the photothermal conversion efficiency of the doped SnSe nanosheets surged from 51.56% to 82.11%, surpassing many previously reported photothermal materials. Furthermore, leveraging these nanosheets with enhanced photothermal conversion efficiency, a solar interfacial evaporation system is constructed. The evaporation rate of 2.17kgm-2h-1 and the efficiency of 96.5% can be achieved at one solar irradiance, and it also has good salt-resistance properties. The findings demonstrate the potential of rare earth ion-doped 2D semiconductor nanosheets in solar water evaporation, paving the way for future sustainable desalination solutions.

Dynamic Imaging of Electrochemically Induced Transformations in Layered Tin Chalcogenide Catalysts.

Understanding the dynamic transformation processes of electrocatalysts during electrochemical reactions is crucial for the development of advanced materials for energy conversion and storage, yet it remains a challenge. Herein, we report the real-time monitoring of the dynamic transformation of a series of layered Sn chalcogenides during electrochemical reduction using a plasmonic imaging method. Taking SnSe2 as an example, we observed a strong firework-like emission diffusing outward from SnSe2 to the surrounding solution under a negative potential. The diffusion coefficient of the observed species is indicative of Sn nanoclusters rather than smaller ions. This study also extends to SnSe and SnS2 nanosheets, demonstrating the general applicability of plasmonic imaging for probing the stability and transformation mechanism of heterogeneous catalysts in electrocatalytic reactions. These insights provide a foundational understanding for designing more stable and efficient electrocatalysts for industrial applications.

In Situ PL Probes the Effect of 2D SnSe Nanosheets on the Crystallization Process of CsPbI2Br Perovskite Solar Cells.

Reducing defects in the active layer is important for improving the crystalline quality of all-inorganic perovskite solar cells (PSCs). Exploring novel additives is one of the most promising approaches to minimize active layer defects. In this work, two-dimensional (2D) SnSe nanosheets with excellent optoelectronic properties are prepared using an ultrasonic exfoliation method. The prepared 2D SnSe nanosheets are introduced into a CsPbI2Br precursor, which reduces the defect formation at grain boundaries and enhances the crystallinity of CsPbI2Br perovskites. We use the in situ photoluminescence (PL) technique to investigate the role of 2D materials in the crystallization process. The results show that SnSe nanosheets primarily shorten the grain boundary merging time and reduce the defect generation during the grain boundary merging stage, thereby regulating the crystallization of perovskite. In addition, SnSe nanosheets passivate uncoordinated Pb atoms at grain boundaries by Se atoms, further reducing the defect density in perovskite. As a result, PSCs exhibit a higher power conversion efficiency (PCE) of 14.24% and a Voc of 1.22 V. This study highlights the role of 2D materials in enhancing the crystalline quality and PCE of PSCs.

Adjustment in phonon scattering through doping to boosting the Near-IR photoresponse performance of p-type SnSe nanosheets

As a p-type semiconductor, layered SnSe has attracted more and more attention because of its great potential application in the field of optoelectronics. However, the strong phonon scattering caused by abundant intrinsic vacancy defects dramatically reduces the performance of carrier transport. It is significant to effectively compensate for the intrinsic defects and reduce the phonon scattering for photodetection materials. In this letter, a novel and simple method is used to reduce the scattering and thus improve the detector performance. The inhibition effect of doping on phonon scattering is systematically studied by experiments and theoretical calculations. The Bi-doped SnSe photodetector exhibits great responsivities of 2.13 A W−1 (447 nm), 1.35 A W−1 (655 nm) and 1.91 A W−1 (980 nm) at 5 V, which are about 2∼3 folds better than those of the undoped device. Furthermore, for the Bi-doped SnSe photodetector, the Ion/Ioff are about 46.7, 20.3 and 30.3 for 447 nm, 655 nm and 980 nm, respectively, which are much higher than those of the SnSe photodetector. The photoluminescence and absorption are performed to confirm the bandgap and defects energy level. Meanwhile, the temperature-dependent current-voltage curves measurement is utilized to prove that the enhancement in response performance is because of the decrease in intensity of phonon scattering, which is attributed to the reduction of scattering centers and the weakening of the effect of vacancy defects on the structural translational asymmetry. All these results evidently illustrate that adjustment in phonon scattering is an effective way to achieve high-performance SnSe photodetectors.

Electrolyte-dependent performance of SnSe nanosheets electrode for supercapacitors

Transition metal chalcogenides (TMC) are widely suggested as electrode materials for electrochemical energy storage devices due to their layered structure. However, the difficult synthesis limits the commercial utilization of these materials. Herein, we report a simple and effective synthesis method to obtain thin films of SnSe electrodes using the solution heating synthesis route. Having an average thickness of 45 nm, the structural and topographical confirmation of the SnSe nanosheets was revealed by XRD, XPS, SEM, and TEM characterizations. The produced SnSe served as electrodes in aqueous three-electrode supercapacitor cells. When tested with KOH electrolyte, it demonstrated a high specific capacitance of 794 F/g and an areal capacitance of 155 mF/cm2 at a scan rate of 5 mV/s. The LiClO4 electrolyte had a specific capacitance of 645 F/g and an areal capacitance of 103 mF/cm2 at a scan rate of 2 mV/s. Furthermore, the SnSe nanosheet electrode maintains 97 % of the maximum capacitance in the LiClO4 electrolyte for 4500 cycles, even at a high scan rate of 100 mV/s. The symmetric solid-state SnSe supercapacitor device fabrication has been carried out by using PVA-KOH and PVA-LiClO4 gel electrolytes. The highest estimated energy density from a fabricated symmetric solid-state (SSC) device is 8.88 Wh/kg at a power density of 2.7 kW/kg. Even at 3.0 kW/kg higher power density, the SSC device retained a reasonably good energy density of 4.3 Wh/kg. Finally, to check the durability of the fabricated SSC device has been carried out for long 5000 CV cycles and the specific capacitance retention was around 96 %. The easy synthesis technique for SnSe nanosheets and binder-free electrode fabrication has a promising application in the production of high-performance energy storage devices. The findings of this study hold significant implications for the advancement of supercapacitor technology, offering insights into the potential of SnSe as a high-performance electrode material and shedding light on the critical role of electrolyte selection in achieving superior supercapacitor performance.

Construction of g-C3N4/SnSe2/H-TiO2 Ternary Heterojunction for High-Performance Photodetectors

Two-dimensional layered materials have been widely used in the field of photodetectors because of their unique photoelectric properties. Among them, the multi-heterojunction based on two-dimensional materials with high carrier separation efficiency is expected to be designed as a high-performance photodetector (PD). This work focuses on the fabrication of g-C3N4/SnSe2/H-TiO2 ternary heterojunctions for photodetectors, obtained by depositing SnSe2 and g-C3N4 nanosheets onto TiO2 nanotube arrays using chemical vapor deposition and impregnation methods, respectively. The formation of the g-C3N4/SnSe2/H-TiO2 ternary heterojunction enhances and broadens absorption in the ultraviolet-visible range. Photoelectrochemical measurements have confirmed that the fabricated g-C3N4/SnSe2/H-TiO2 ternary heterojunction photodetector exhibits remarkable light detection capabilities at 370, 450, and 520 nm, meaning broadband photodetection behavior. Notably, under light illumination of 370 nm wavelength, it demonstrates a high responsivity of 2.742 A W−1, an impressive detectivity of 5.84 × 1010 Jones, an external quantum efficiency of 9.21 × 102 %, and excellent stability. This high performance can be attributed to the effective separation and transfer of photogenerated carriers within the ternary heterojunction, significantly enhancing the photoresponse. The construction of the novel broadband-responsive ternary g-C3N4/SnSe2/TiO2 heterojunction holds promise for driving the future development of wideband, high-performance, and highly integrated photodetectors.

Three Birds with One Stone: Multifunctional Separators Based on SnSe Nanosheets Enable High‐Performance Li‐, Na‐ and K‐Sulfur Batteries

AbstractAlkali metal‐sulfur batteries (MSBs) are one of the most promising next‐generation energy storage technologies due to their high energy density and potential for low cost. They are nonetheless constrained by the sluggish conversion of metal polysulfides (MPS) during the charge/discharge process. Herein, a multifunctional separator able to trap the MPS and catalyze their conversion in the three main MSB chemistries, Li‐, Na‐, and K‐MSBs, is demonstrated. More in detail, SnSe nanosheets are introduced as additive into the cathode side of the glass microfiber (GF) separator of the MSB. Taking lithium‐sulfur batteries (LSBs) as an example, it is demonstrated that the GF‐SnSe separator (GF@SnSe) shows strong chemical affinity to lithium polysulfides (LiPS) and superior catalytic activity, inhibiting the transport of LiPSs to the anode and accelerating their conversion. Combining experimental and calculation results, the SnSe additive is shown to decrease the Li2S decomposition energy barrier. Overall, GF@SnSe separators provide significantly improved LSB rate performance and cycling stability with a 0.049% capacity decay per cycle. Besides, the GF@SnSe separator promotes the electrochemical performance of sodium‐sulfur and potassium‐sulfur batteries. Overall, this work presents a significant advancement in the development of multifunctional separators in LSBs as well as the emerging Na‐S and K‐S systems.

Improved performance of solar cells using chemically synthesized SnSe nanosheets as light absorption layers

We report the method to fabricate SnSe nanosheet (NSs) coated solar cells with very high performance compared to similar solar cells previously reported using chemically synthesized SnSe nanocrystals. SnSe NSs do not contain toxic metals and are promising materials for the top layer of tandem solar cells. SnSe NSs synthesized using the hot injection method were not suitable for coating as a light absorption layer because of their nonuniform size and tendency to aggregate. The one-pot synthesis produced SnSe NSs with uniform size, making them suitable for fabricating flat and homogeneous films when mixed with conductive polymers. The photoelectric conversion efficiency (PCE) of 4.8% was achieved using films with a sheet coverage of 14.2% of SnSe NSs. The PCE value was nearly two orders of magnitude higher than that of previous similar SnSe-coated solar cells. SnSe NSs coated films, which can be easily produced unlike vapor phase methods, were shown to have the potential to make an important contribution to the field of photovoltaic power generation.

Surface trapping induced negative photoconductivity in Au nanoparticles functionalized SnO2/SnSe2 nanosheets under visible and NIR light

In this study, we report negative photoconductivity in SnO2/SnSe2 nanosheets. We synthesized 2D n-type SnSe2 nanosheets by the hydrothermal route and observed highly stable and repeatable negative photoconductivity (NPC) in the presence of both visible (532 nm) and near-infrared (NIR, 905 nm) irradiation. The existence of native SnO2 skin on SnSe2 nanosheets was confirmed with X-ray photoelectron spectroscopy (XPS). Negative photoresponse was improved significantly after Au nanoparticles (∼3.4 nm) functionalization of SnO2/SnSe2 nanosheet. Au-SnO2/SnSe2 exhibited responsivity/detectivity of 47.55 mA/W & 1.49 × 1010 Jones and 47.8 mA/W &1.5 × 1010 Jones at 10 V bias in visible and NIR light intensity of 50 µW/cm2, respectively, and quite a faster fall time of 841 µs and 791 µs in NIR exposure. The origin of NPC in SnSe2 is attributed to the trapping of photogenerated hot carriers by surface adsorption of oxygen in ambient air. The NPC was further increased due to a significant increment of dark current (as well as Idark/Ilight) after Au nanoparticles functionalization on SnO2/SnSe2.

Showcasing a self-powered photoelectrochemical photodetector with ultrasonically exfoliated SnSe2 nanosheets

Showcasing a self-powered photoelectrochemical photodetector with ultrasonically exfoliated SnSe2 nanosheets

Catechol determination based on two dimensional SnSe nanosheets modified glassy carbon electrode with enhanced sensitivity

Catechol determination based on two dimensional SnSe nanosheets modified glassy carbon electrode with enhanced sensitivity

Effectively coupling of SnSe2nanosheet with N, Se co-doped carbon nanofibers as self-standing anode for lithium-ion batteries.

Tin selenides possess layered structure and high theoretical capacity, which is considered as desirable anode material for lithium-ion batteries. However, its further development is limited by the low intrinsic electrical conductivity and sluggish reaction kinetics. Herein, a well-designed structure of SnSe2nanosheet attached on N, Se co-doped carbon nanofibers (SnSe2@CNFs) is fabricated as self-standing anodes for lithium-ion batteries. The integration of structural engineering and heteroatom doping enables accelerated electrons transfer and rapid ion diffusion for boosting Li+storage performance. Impressively, the flexible SnSe2@CNFs anodes exhibit inspiring capacity of 837.7 mAh g-1after 800 cycles at 1.2 C with coulombic efficiency almost 100% and superior rate performance 419.5 mAh g-1at 2.4 C. The kinetics analysis demonstrates the pseudocapacitive characteristic of SnSe2@CNFs promotes the storage property. This work sheds light on the hierarchical electrode construction towards high-performance energy storage applications.

Broadband, Plasmon‐Modified SnSe2 Photodetector Based on LNOI Thin‐Film Platform

AbstractLithium niobate on insulator (LNOI) is widely recognized as an essential optoelectronic integration platform due to its unique ferroelectric properties and photorefractive effect. However, the wide bandgap and weak absorption of lithium niobate limit its further application in integrated photodetection field. To address this issue, encapsulating silver nanoparticles within the LNOI structure are proposed to manipulate the light field distribution of modified lithium niobate through the localized surface plasmon resonance (LSPR) effect and utilize the modified lithium niobate thin film as a functional substrate to tailor the optoelectronic properties of surface SnSe2 nanosheets, significantly enhancing their photodetection capabilities. The photocurrent of the SnSe2 photodetector based on LNOI with embedded Ag nanoparticles is enhanced by up to 1912 times compared to that on the original LNOI under the same conditions, which represents the highest reported plasmonic‐induced photodetection enhancement. This work deepens the basic research on plasmonic‐modified 2D materials and ferroelectric materials, which promotes the development of on‐chip photodetectors and the realization of fully functional photonic circuits that integrate all essential components on a single chip.

Chemically bonded MXene/SnSe2 composite with special structural transformation as a high-performance anode for lithium and potassium ions battery

Sn-C bonding coupled MXene/SnSe2 composite with SnSe2 nanosheets vertically coating on the MXene surface was prepared successfully by the solvothermal method, in which MXene matrix etched separately by HF and LiF/HCl was used to explore the improving effect on the electrochemical performance of SnSe2. It is found that MXene etched by HF acid shows more obvious accordion-like structure with larger layer spacing, and its composite with SnSe2 demonstrates better lithium and potassium storage properties. When employed as potassium-ion batteries (PIBs) anode, MXene/SnSe2 electrode can deliver a reversible capacity of 222.8 mAh·g−1 till 300 cycles at the current density of 200 mA·g−1. As an anode for lithium-ion batteries (LIBs), MXene/SnSe2 could provide high reversible capacity (515.6 mAh·g−1 after 300 cycles at 200 mA·g−1) and rate capacity (1015.1 mAh·g−1 at 500 mA·g−1 and 496.2 mAh·g−1 at 5000 mA·g−1). Even at 2000 mA·g−1, the capacity of MXene/SnSe2 can be maintained at 322.6 mAh·g−1 after 500 cycles. Further analysis by ex-situ SEM finds that the MXene/SnSe2 electrode undergoes structural reconstruction at the high current density of 2000 mA·g−1. In the first few cycles, SnSe2 nanosheets are changed into a network structure and then in-situ pulverized into many small nanoparticles, all which immerged on MXene surface and between layers. Although MXene/SnSe2 electrode experiences structural transformation, it retains apparent layered structure. This provides a fast channel for electrons and ions migration, resulting in higher Li+ diffusion rate and diffusion-controlled storage capacity. It is believed that the work could be acted as a reference for design composite with MXene and used for anode as well as other materials.

Unveiling the role of electrode polarization in modulating dielectric and electro-optical properties of SnSe dispersed nematic liquid crystal

This study explores the impact of electrode polarization on SnSe nanosheets blended with liquid crystal cells and investigates how impurity ions influence the performance of the liquid crystal.

Achieving pH‐universal electrosynthesis of formate under industrial‐grade current density by enriched selenium vacancies

AbstractElectrosynthesis of formate via CO2 reduction (CO2ER) is of great significance for completing carbon cycle, however, low CO2 utilization efficiency caused by slow reaction kinetics greatly hinder its large‐scale application. Herein, we reported a ~50 nm‐thick SnSe2 nanosheets with enriched Se vacancies, which exhibits an excellent catalytic activity for pH‐universal formate electrosynthesis. In alkaline, neutral, and acidic electrolytes, this catalyst reached up to the maximum formate Faradaic efficiencies of 94.1%, 81.7%, and 78.1%, respectively. Under corresponding pH conditions, the maximum formate partial current densities achieved 800, 568, and 495 mA cm−2, respectively. Kinetic experiments combined with in situ electrochemical spectroscopy unveiled that the abundant Se vacancies promoted the dissociation of water to produce more protons, thereby accelerating the formation rate of key *OOCH intermediate. Theoretical calculations validated that the formation of enriched Sn active sites lowered the energy barrier for the *OOCH formation, eventually facilitating the formate electrosynthesis process.

Two-dimensional tin diselenide as the saturable absorber for passively Q-switched Er:YAP 3 μm solid-state laser

A passively Q-switched (PQS) Er:YAP laser at ∼3 μm with the two-dimensional saturable absorber (SA) tin diselenide (SnSe2) nanosheet as SA was successfully demonstrated for the first time. Under the maximum absorbed pump power of 4.0 W, the obtained continuous-wave maximum output power of Er:YAP laser was 258 mW with a corresponding slop efficiency of 7.18%. In the PQS experiment, laser pulses with the shortest pulse duration of 198 ns were yielded with a repetition rate of 317 kHz under the maximum absorbed pump power of 4.0 W, and the corresponding single pulse energy and pulse peak power were 0.66 µJ and 3.3 W, respectively. The investigation indicates that SnSe2 has the potential to be an outstanding laser modulator for PQS solid-state laser at 3 μm wavelength.

Epitaxial growth strategy for construction of Tm3+ doped and [hk1] oriented Sb2S3 nanorods S-scheme heterojunction with enhanced photoelectrochemical performance

With the advantages of high absorption coefficient, non-toxicity and low cost, Sb2S3 shows great potential as a narrow bandgap photocathode in the field of PEC hydrogen production. However, the separation and transportation of photogenerated carriers in the reported Sb2S3 photocathode are inefficient due to its anisotropy and the Fermi level being pinned by deep-level defects. Therefore, Tm3+ doped Sb2S3 nanorods with the selective carrier transport orientation were epitaxially grown on SnSe2 film by a simple hydrothermal strategy to modulate the defect property of Sb2S3, optimize carrier transportation and separation efficiency, and improve the PEC performance of photoelectrodes. Experimental results showed that the doping of Tm3+ weakening the Fermi level pinning while achieving the conversion of Sb2S3 to n-type conducting property. The S-scheme heterojunction formed by Tm3+ doped Sb2S3 nanorods labeled as Sb2S3: Tm3+ and SnSe2 nanosheets provided a stronger driving force to optimize carrier interface transportation. The photocurrent density (−0.91 mA cm−2) is increased about 18 times compared to the pristine Sb2S3 photocathode. This work developed an effective doping strategy to weaken the Fermi level pinning and provided a novel idea for the epitaxial growth of Sb2S3 nanorods to optimize the carrier transportation.