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Ultra-small colloidal heavy-metal-free nanoplatelets for efficient hydrogen generation
摘要： Metal chalcogenide semiconducting nanoplatelets exhibit a broad absorption spectrum, as well as thickness-dependent optical and electronic properties. As such, they may be used as building blocks in a variety of optoelectronic devices. The direct synthesis of heavy-metal-free ultra-small sized nanoplatelets is still challenging, due to the inherent limits in existing synthetic approaches. Here, we report an efficient template-assisted cation-exchange route to synthesize heavy metal free metal chalcogenide nanoplatelets that are optically active in the near infrared. The SnSe nanoplatelets, whose lateral dimension is 6-10 nm, exhibit a quantum yield of 20%. The nanoplatelets are applied as light absorbers in a photoelectrochemical (PEC) system for hydrogen generation, leading to a saturated photocurrent density of 7.4 mA/cm2, which is a record for PEC devices using heavy metal-free colloidal quantum dots or nanoplatelets under identical measurement conditions. Our results indicate that quasi-zero-dimensional SnSe nanoplatelets hold great potential as efficient light absorbers for emerging optoelectronic technologies.
关键词： nanoplatelets,cation exchange,optoelectronic technologies,SnSe,hydrogen generation
更新于2025-11-19 16:51:07
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Linear and Nonlinear Optical Properties of Few-Layer Exfoliated SnSe Nanosheets
摘要： Monochalcogenides of group IV elements have been considered as phosphorene analogs due to their similar crystal and electronic structure. Here, few-layer SnSe nanosheets are synthesized by a sonication-assisted liquid phase exfoliation process and their linear and nonlinear optical properties are examined. The as-exfoliated few-layer (FL) SnSe demonstrates layer thickness from 2 to 10 nm and lateral size of 150 nm with high crystallinity. Optical measurement confirms the layer-number dependent bandgap, which is also corroborated by first-principle calculation. In addition, the FL SnSe shows a transition from saturable absorption to reverse saturable absorption with the increase of pumping power, and the nonlinear absorption is characterized by an ultrafast response time of picosecond scale. The nonlinear optical response in FL SnSe could be explained by defect-involved recombination of photogenerated carriers as well as the Auger scattering process, which is further enhanced by structural two-dimensionality.
关键词： nonlinear optics,phosphorene analogue,SnSe,liquid-phase exfoliation,2D semiconductors
更新于2025-09-23 15:23:52
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Sensitivity Enhancement of a Surface Plasmon Resonance with Tin Selenide (SnSe) Allotropes
摘要： Single layers of tin selenide (SnSe), which have a similar structure as graphene and phosphorene, also show excellent optoelectronic properties, and have received much attention as a two-dimensional (2D) material beyond other 2D material family members. Surface plasmon resonance (SPR) sensors based on three monolayer SnSe allotropes are investigated with the transfer matrix method. The simulated results have indicated that the proposed SnSe-containing biochemical sensors are suitable to detect different types of analytes. Compared with the conventional Ag-only film biochemical sensor whose sensitivity is 116°/RIU, the sensitivities of these SnSe-based biochemical sensors containing α-SnSe, δ-SnSe, ε-SnSe, were obviously increased to 178°/RIU, 156°/RIU and 154°/RIU, respectively. The diverse biosensor sensitivities achieved with these three SnSe allotropes suggest that these 2D materials can adjust SPR sensor properties.
关键词： SPR sensor,high sensitivity,SnSe allotrope
更新于2025-09-23 15:22:29
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Effect of substrate temperature on structural and thermoelectric properties of RF-magnetron sputtered SnSe thin film
摘要： SnSe is a potential thermoelectric material, but there are few reports about the thermoelectric properties of the film. In this work, SnSe thin films were deposited on glass substrates by RF magnetron sputtering from SnSe alloy target. The effect of substrate temperature on the structural and thermoelectric properties was investigated. It was found that the columnar grains and the surface roughness of the films increase with increasing the substrate temperature. The film deposited at 558 K exhibited a high crystalline quality and stoichiometric composition, which has a maximum power factor of 1.4 uWcm-1K-2 at 575 K. The results of this work demonstrate the importance of high substrate temperature to obtain high thermoelectric performance SnSe films.
关键词： SnSe thin film,sputtering,thermoelectric properties
更新于2025-09-23 15:22:29
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Enhancement of monolayer SnSe light absorption by strain engineering: A DFT calculation
摘要： Strain effects on the electronic and optical properties of monolayer SnSe is studied by APW + lo method in DFT framework. The applied strains cause direct-indirect transition of SnSe band gap which is mainly constructed by s/p hybridization. The armchair εac and zigzag εzz reduce the unstrained band gap of 1.05 eV down to 0 eV at 12% compression, but at 12% tension, the band gap decreases to 0.726–0.804 eV. The band gap always increases under biaxial strain εb at at 12% compression to 12% tension. We observe an enhancement of real ε1(ω) and imaginary ε2(ω) parts of dielectric function by 14% ? 30% of magnitude, wider peak distribution to infrared and ultra-violet regions, and appearance of new peaks in the ε1(ω) and ε2(ω) spectrums. As a consequence, the light absorption α(ω) is significantly enhanced in the ultra-violet region and the absorption even starts at lower energy at infrared region.
关键词： Strain,Optical properties,Electronic band structure,First-principles,Monolayer SnSe
更新于2025-09-23 15:22:29
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Influence of Local Heterojunction on the Thermoelectric Properties of Mo-SnSe Multilayer Films Deposited by Magnetron Sputtering
摘要： Mo-SnSe multilayer films were deposited by multi-step magnetron sputtering. The Mo-SnSe multilayer films are then annealed, and the new phases including SnSe2 and MoSe2 are observed by x-ray diffraction and Raman spectroscopy. Scanning electron microscopy reveals that the SnSe exhibits the columnar grain structure with sizes from 50–100 nm. The high-resolution transmission electron microscopy shows the SnSe2 is dispersed at the boundary of the columnar grain and the local MoSe2/SnSe heterojunction is formed in the interior of the columnar grain. The influence of Mo content on the thermoelectric properties of SnSe thin films was investigated. A maximum power factor of 0.44 μW cm?1 K?2 was obtained for a 2.6 at.% Mo-doped SnSe thin film at 576 K, which is higher than that of a SnSe thin film deposited under the same conditions.
关键词： thermoelectric properties,heterojunction,SnSe films,sputtering
更新于2025-09-23 15:22:29
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Effect of film thickness and evaporation rate on co-evaporated SnSe thin films for photovoltaic applications
摘要： SnSe thin films were deposited by a co-evaporation method with different film thicknesses and evaporation rates. A device with a structure of soda-lime glass/Mo/SnSe/CdS/i-ZnO/ITO/Ni/Al was fabricated. Device efficiency was improved from 0.18% to 1.02% by a film thickness of 1.3 mm and evaporation rate of 2.5 ? s?1 via augmentation of short-circuit current density and open-circuit voltage. Properties (electrical, optical, structural) and scanning electron microscopy measurements were compared for samples. A SnSe thin-film solar cell prepared with a film thickness of 1.3 mm and evaporation rate of 2.5 ? s?1 had the highest electron mobility, better crystalline properties, and larger grain size compared with the other solar cells prepared. These data can be used to guide growth of high-quality SnSe thin films, and contribute to development of efficient SnSe thin-film solar cells using an evaporation-based method.
关键词： SnSe thin films,film thickness,co-evaporation,photovoltaic applications,evaporation rate
更新于2025-09-23 15:21:01
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Synthesis of SnSe quantum dots by successive ionic layer adsorption and reaction (SILAR) method for efficient solar cells applications
摘要： Quantum dots (QDs) are one of the promising materials in the development of third-generation photovoltaics. QDs have the advantage of multiple exciton generation (MEG), high absorption coefficient and tuneable bandgap, low cost and easy synthesis. The QDs act as analogues to dye molecules in QD sensitized solar cells (QDSSCs) when compared with traditional dye-sensitized solar cells (DSSCs). Extending the absorption range of quantum dots is one of potential solutions for enhancing photoconversion efficiencies. The sensitization of SnSe quantum dots on theTiO2 mesoporous layers is carried by a successive ionic layer adsorption and reaction (SILAR) method in a glove box. The advantages of SILAR method are a high loading rate and wide coverage of the TiO2 matrix by the quantum dots. The device has exhibited a photoconversion efficiency of 0.78% which is the known best among the SnSe quantum dot-based solar cells.
关键词： Solar cell,SILAR method,Photovoltaic efficiency,Sulphide-polysulphide,Light trapping,SnSe Quantum dots,QDSSC
更新于2025-09-23 15:19:57
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Enhanced performance of SnSe-Graphene hybrid photonic surface plasmon refractive sensor for biosensing applications
摘要： In this study, we developed a simple hybrid structure and an appropriate numerical analysis method for a prism-based surface plasmon refractive index biosensor by using an angular interrogation domain technique. The performance parameters were determined in terms of the sensitivity, detection accuracy (DA), and quality factor (QF). The results demonstrated the improved overall performance of the proposed method. The proposed sensor comprised a prism filled with a hybrid of gold (Au), alpha tin selenide (α-SnSe), and graphene, and a sensing medium. Monolayers of α-SnSe with a similar structure to graphene and phosphorene have exceptional optoelectronic properties and they have attracted much attention as two-dimensional (2D) materials in a similar manner to other 2D material family members. and its sensitivity was higher than those of previously reported sensors. All of the performance parameters were enhanced for this hybrid sensor, which is not possible with sensors based only on graphene. Increasing the number of graphene-only layers improved the sensitivity but decreased the DA and QF. The effect of the electric field distribution on the inserted graphene layers was analyzed with the finite difference time domain (FDTD) technique using Lumerical FDTD solution commercial software. The proposed biosensor may facilitate novel sensing applications.
关键词： full width at half maximum,sensitivity,SnSe,surface plasmon refractive sensor,graphene
更新于2025-09-19 17:13:59
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Wafer-size growth of 2D layered SnSe films for UV-Visible-NIR Photodetector Arrays with High Responsitivity
摘要： Due to its excellent electrical and optical property, tin selenide (SnSe), a typical candidate of two-dimentional (2D) semiconductors, has attracted great attention in the field of novel optoelectronics. However, the large-area growth of high-quality SnSe films still remain a great challenge which limit its practical applications. Here, wafer-size SnSe ultrathin films with high uniformity and crystallization are deposited via a scalable magnetron sputtering method. The results show that the SnSe photodetector is highly sensitive to a broad wavelength in the UV-Visible-NIR range, especially showing an extremely high responsivity of 277.3 A W -1 with the corresponding external quantum efficiency of 8.5×104% and detectivity of 7.6×1011 Jones. These figures-of-merits are among the best performance for the sputter-fabricated 2D photodetector devices. The photodetecting mechanisms based on a photogating effect induced by the trapping effect of the localized defects are discussed in details. The results indicate that the few-layered SnSe films from the sputtering growth would have great potential in designing high-performance photodetector arrays.
关键词： tin selenide,detectivity,responsivity,optoelectronics,SnSe,UV-Visible-NIR,2D semiconductors,external quantum efficiency,photodetector,magnetron sputtering
更新于2025-09-19 17:13:59