Tin Sulfide Thin Films Research Articles

Investigation of sol-gel derived CZTS thin film based solar cell: Experimental and theoretical approach

The successful deposition of eco-friendly Copper Zinc Tin Sulphide (CZTS) thin films on soda lime glass substrates by spin-coating technique has been investigated. The films were deposited by varying the Cu/(Zn + Sn) ratio, ranging from 0.25 to 1.25. The deposited films exhibited a polycrystalline structure with a single kesterite phase with a preferred orientation along the (112) plane. The size of the crystallites was found to be in the range of 14 to 16.6 nm. The higher absorbance of the films was found to be near infrared, with a band gap of 1.56 to 1.72 eV. Higher carrier concentrations of CZTS films were observed with p-type conductivity. The efficiency of CZTS solar cells was studied using the simulator SCAPS-1D. Theoretical graphs of J-V efficiency were also drawn and calculated theoretically.

Simulation Study for Nb‐Doped MoS2${\rm MoS}_2$ Layer in CZTS‐Based Solar Cells: Assessment of Challenges

AbstractThe unintentional formation of a layer as a reaction product between the copper zinc tin sulfide (CZTS) thin film and the Mo back contact reduces cell efficiency due to high sheet resistance and carrier recombination. To limit the formation of , an intentionally grown p‐type Nb‐doped layer can serve as an effective hole transport layer. This study presents a detailed study and calculations for CZTS/Mo‐based solar cells, providing guidelines for calibration. Optimizing cell efficiency is influenced by various interconnected factors in Nb‐doped . While a high carrier concentration in Nb‐doped is assumed to enhance efficiency, other parameters such as band state, optical absorption, and carrier mobility also play crucial roles and can limit cell performance. This simulation study evaluated the effect of Nb‐doped layers with different carrier concentrations to determine the optimal conditions for this p‐type layer. This work reveals that a very thin layer (13 nm) of Nb‐doped p‐type can achieve a maximum efficiency of 11.34% (with = 1.5 ) and that for an Nb‐doped p‐type 62 nm is 15.82 % (with = 4.03 ).

An Investigation on Structural, Morphological, Optical, and Electrical Properties of Copper Zinc Tin Sulfide (CZTS) Thin Films Prepared by SILAR Method

An Investigation on Structural, Morphological, Optical, and Electrical Properties of Copper Zinc Tin Sulfide (CZTS) Thin Films Prepared by SILAR Method

Impact of post deposition treatment on optoelectrical and microstructural properties of tin sulfide thin film for photovoltaic applications

Tin sulfide (SnS) has attracted significant interest due to its advantageous optoelectrical characteristics and abundant presence in nature. Post-deposition treatments (PDTs) are frequently employed to enhance the crystallinity of chalcogenide-based solar cells. This study examined the influence of the post-deposition heat treatment procedure on thermally evaporated SnS thin film. The post-deposition annealing process, as determined by XRD and AFM studies, supplies the necessary thermal energy for re-crystallization, potentially resulting in a modification of crystallite dimensions. The occurrence of Sn-S polytypes was examined using Raman and XPS studies. Annealing causes changes in the optical properties, as observed through optical analysis, which can be attributed to the improvement in crystallinity. Subjecting the material to annealing at temperature of 300 °C greatly improves both mobility and conductivity, while also causing a change in conduction type. The observed variations in conduction type are attributed to the differing ratios between the amounts of Sn2+ and Sn4+. This strategy offers a novel route for the fabrication of thin-film photovoltaic cells by using a p-type buffer layer.

Surfaces properties correlation with optical parameters of thickness dependent self-affine nanostructured SnS thin films: A study based on scaling law

Fractal concepts are employed to investigate the surface properties of tin sulfide (SnS) thin films, which are deposited on Fluorine-doped tin oxide (FTO)- coated glass substrates by the thermal evaporation (TE) technique. The surface topography of each deposited film is captured by AFM. The fractal dimensions of the AFM image were extracted through the Higuchi algorithm, and it is found that the thinner sample surface exhibits the maximum fractal dimension. The autocorrelation function and height-height correlation function are used to investigate the self-affinity behavior of surfaces. Dynamic surface roughening is characterized by different scaling exponents, such as the roughness exponent, the growth exponent, the dynamic scaling exponent, and the steepening exponent. It was observed that the values of average roughness, interface width, lateral correlation length, and mean square local slope are strongly influenced by film thickness. The self-affine fractal nature of thin film is estimated by the roughness exponent; however, island- or mound-type growth with quick surface roughening behavior is predicted by the growth exponent and the dynamic scaling exponent. Further, we have tried to correlate the optical properties such as transmission, reflection, and refractive index with the fractal dimension of SnS thin film. The increase in optical reflection with decreasing roughness indicates that absorber surfaces of the best crystalline films have the lowest reflectivity. The present results suggest that such surfaces, having a maximum fractal dimension and minimum optical reflectance, can be used as photon absorber layers for advanced solar cell devices.

Recent Progress and Challenges in Controlling Secondary Phases in Kesterite CZT(S/Se) Thin Films: A Critical Review

Kesterite-based copper zinc tin sulfide (CZTS) and copper zinc tin selenide (CZTSe) thin films have attracted considerable attention as promising materials for sustainable and cost-effective thin-film solar cells. However, the successful integration of these materials into photovoltaic devices is hindered by the coexistence of secondary phases, which can significantly affect device performance and stability. This review article provides a comprehensive overview of recent progress and challenges in controlling secondary phases in kesterite CZTS and CZTSe thin films. Drawing from relevant studies, we discuss state-of-the-art strategies and techniques employed to mitigate the formation of secondary phases. These include a range of deposition methods, such as electrodeposition, sol-gel, spray pyrolysis, evaporation, pulsed laser deposition, and sputtering, each presenting distinct benefits in enhancing phase purity. This study highlights the importance of employing various characterization techniques, such as X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, for the precise identification of secondary phases in CZTS and CZTSe thin films. Furthermore, the review discusses innovative strategies and techniques aimed at mitigating the occurrence of secondary phases, including process optimization, compositional tuning, and post-deposition treatments. These approaches offer promising avenues for enhancing the purity and performance of kesterite-based thin-film solar cells. Challenges and open questions in this field are addressed, and potential future research directions are proposed. By comprehensively analyzing recent advancements, this review contributes to a deeper understanding of secondary phase-related issues in kesterite CZT(S/Se) thin films, paving the way for enhanced performance and commercial viability of thin-film solar cell technologies.

Influence of deposition potential and substrate characteristics on the photovoltaic conversion efficiency of p-SnS absorbing layers

In this study, thin films of tin sulfide (SnS) deposited on indium-doped tin oxide (ITO) and fluorine-doped tin oxide (FTO) substrates using Sn-S electrodeposition were systematically investigated. Notably, a novel non-toxic sulfur precursor was employed, emphasizing its role in ensuring the safety and environmental friendliness of the synthesis process. The research was focused on the influence of deposition potential and substrate type on the physical properties of SnS films. X-ray diffraction (XRD) analysis disclosed distinct peaks corresponding to orthorhombic SnS phase planes (101), (111), and (040). Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) revealed a uniform distribution of essential components, particularly notable at −0.7 V on ITO and −0.9 V on FTO substrates. Raman spectroscopy identified characteristic peaks at 90 cm−1 and 222 cm−1. UV–visible spectrophotometry highlighted alterations in the optical band gap of SnS films on ITO (1.93 eV to 1.57 eV) and FTO (2.13 eV to 1.98 eV). Mott-Schottky analysis revealed consistent p-type conductivity behavior in the SnS layer, while both ITO and FTO layers exhibited n-type conductivity behavior. This characterization underscores the distinct electronic properties of each layer, providing valuable insights for the development of advanced optoelectronic devices. Electrochemical Impedance Spectroscopy (EIS) results demonstrated a significant reduction in charge transfer resistance (Rct) of SnS films on ITO at −0.7 V. The solar cell efficiency of the SnS absorber layer reached 2.2% on ITO at −0.7 V, contrasting with 1.47% on FTO at −0.9 V.

Role of triethanolamine complexing agent in chemical bath deposition of tin sulfide thin films: Microstructural and optical properties

This paper reports the experimental results studying the structure, optical and dielectric properties of tin monosulfide thin films. Tin monosulfide (SnS) films were deposited on glass substrate by chemical bath deposition to study the role of triethanolamine (TEA: complexing agent) concentration on the film properties. X-ray diffraction spectra reveal that the films exhibit mainly cubic phase which remain stable over the range of TEA concentration (3.0 M − 5.0 M). FTIR spectra indicate the S-Sn bond stretching in all films. Raman spectroscopy analysis shows the presence of minor trace of secondary SnS2 phase (along with main cubic π-SnS phase) in all films. SEM micrographs show cauliflower-like surface morphology of all films. Optical results reveal that the films possess high value of absorption coefficient (≥105 cm−1) in the visible region. Direct optical transition behavior is observed in all films. From Tauc plots, the calculated optical band gap (Eg) varies from 1.79 eV to 1.91 eV with the variation in TEA concentration. The dielectric constant, refractive index and an extinction coefficient are also calculated and observed to decrease with increasing TEA concentration. Experimental results suggest that an appropriate concentration of a complexing agent (TEA) can be chosen to obtain crystalline films without deterioration of crystalline structure and phase, not effecting Eg significantly.

Microstrain effects of laser-ablated Au nanoparticles in enhancing CZTS-based 1 Sun photodetector devices.

Copper zinc tin sulfide (CZTS) thin films were synthesized on soda lime glass using pulsed laser deposition (PLD) at room temperature. Introducing gold nanoparticles (AuNPs) in a sandwich structure led to increased CZTS particle size and a shift in the localized surface plasmon resonance (LSPR) peak of the AuNPs, influenced by different laser energy levels. The absorption measurements revealed intriguing behavior across the visible and near-infrared (NIR) regions, making these films appealing for 1 Sun photodetectors. Furthermore, the presence of AuNPs in the sandwich structure reduced microstrain effects, measuring 1.94 × 10-3 compared to 3.38 × 10-3 in their absence. This reduction directly enhances carrier transport, which is particularly beneficial for accelerating the performance of photodetector devices. This effect of AuNPs also contributed to higher dielectric coefficients, further improving the photodetector performance. Under 1 Sun illumination conditions, this enhancement resulted in a rapid rising time of 95.4 ms, showcasing the potential for faster photodetection.

Design and Optimization of Copper Zinc Tin Sulfide (CZTS) Thin Film Solar Cell

Design and Optimization of Copper Zinc Tin Sulfide (CZTS) Thin Film Solar Cell

SILAR Deposition of Sns Thin Films for Possible Device Applications

Successive Ionic Layer Adsorption and Reaction (SILAR) was used to deposit tin sulphide (SnS) thin films on glass substrates at temperature of 450C.Sodium thiosulphateNa2S2O3solution was used as the anionic precursor, tin chloride SnCl2 solution as the cationic precursor and EDTA as complexing agent. The samples were subjected to annealing at the temperature range of 2000C and 250oC). High transmittance values were obtained in both Samples C and D in the UV(70% -72%) and (75% - 89%) respectively atthe wavelength range of (350nm-400nm) which maintains linear characteristics through the visible to near infrared regions (NIR) of the electromagnetic spectrum. This high transmittance implies that it can be useful in the areas of solar energy and opto-electronic applications. The Energy band gap (Eg) is obtained using the relation (αhv)2= A (hv-Eg) where A is constant, hv is the photon energy, Eg is the energy band gap and α is the absorption coefficient. Direct band gap value of 2.90±0.05eV is obtained for sample C while a direct band gap of 2.70±0.05eV is obtained for sample D. The two samples have average band gap of 2.8±0.05eV.

Enhancing the optoelectronic performance of CZTS thin films through cobalt doping via nebulizer-assisted spray pyrolysis technique

In the current investigation, the influence of cobalt doping on the optoelectronic performance of Copper Zinc Tin Sulfide (CZTS) thin films is analyzed. An economic route of synthesis is achieved by employing nebulizer-assisted spray pyrolysis technique. The cobalt concentration is varied from 1 to 5 wt%. The structural, morphological, optical and electrical studies were also made to understand the underlying mechanism that supports the enhancement of photo detecting-capability of these films. It is observed from the XRD studies that initially the doped cobalt replaces zinc in the CZTS lattice. When the concentration of Co was increased beyond 3 wt%, in addition to CZTS we could observe the phase of Copper Cobalt Tin Sulfide (CCTS). At higher concentration the samples exhibit the presence of two phases simultaneously with CCTS as dominant phase. Morphological images from SEM show larger distinct particles for 3% Co doped CZTS. A better absorption in the visible region is witnessed for all the films. The band gap was found to increase with the increase in the concentration of the dopant atom upto 3 wt%. The photoluminescence analysis supports a near-band edge emission around 735 nm. The photocurrent was found to be maximum for 3% Co doped CZTS sample. The rise time and fall time of Co-doped samples becomes halved when compared with the pristine sample. Our research demonstrates the potential applications of CZTS:Co thin films in the realm of photodetectors.

Influence Annealing Process on Structural and Optical Properties of SnS Thin Films

Thin film technology has helped offer an understanding of the crystalline structure of substances, further to the characteristics of electronic transitions and how they are used effectively in different applications. This research focused on the effect of the process of annealing on the structural and optical characteristics of tin sulfide (SnS) thin films. The technique of thermal evaporation was used to synthesize the film samples under a vacuum of about 10–7 mbar. The coated SnS thin films were annealed at 200 °C and the structural and optical characteristics parameters, such as absorbance and transmittance, as well as optical bandgap and band-tail energies in the range )300–1150( nm, were discussed. Under the influence of the annealing process, the average crystal size changed from 14 nm to 11 nm. The energy gap value increased from 1.53 eV to 1.85 eV, while Urbach energy was seen to reduce from 0.913 eV for fabricated samples to be 0.824 eV after the annealing process.

Synthesis and characterization of lithium-doped copper zinc tin sulfide (CZTS) thin films

The non-toxic nature and remarkable optoelectronic properties of kesterite (Cu2ZnSnS4 and CZTS) make CZTS a potential candidate for solar cell absorber layer material. Since alkali metal doping has shown a performance boost of active layers of solar cells, this work investigates the effects of significant lithium doping on sol-gel-produced CZTS thin films. CZTS- and lithium (Li)-doped CZTS thin films were prepared using the spin coating technique. The variation of structural, morphological, and optical properties of CZTS due to Li-doping has been studied by x-ray diffraction, scanning electron microscopy, and UV–visible spectroscopy techniques. All the synthesized LixCu2−xZnSnS4 (x = 0, 0.2, 0.4, 0.6) films showed fine crystallinity with average crystallite sizes of 4.745, 6.013, 6.255, and 6.404 nm, respectively. The average grain size decreases from 0.336 to 0.310 µm via increasing Li concentration. The inclusion of Li increased the bandgap energy ranges from 1.5 to 1.808 eV. The Li0.6Cu1.4ZnSnS4 thin showed the highest absorption coefficient of 3.505 × 104 cm−1 among all the prepared thin films. A high optical conductivity over 1014 s−1 was observed for CZTS, which further increased with an increased Li concentration. The synthesized structures showed enhanced characteristics suitable for solar cell application.

Exploration of thioacetamide molar concentration on the physical properties of chemically deposited tin sulfide thin films

Exploration of thioacetamide molar concentration on the physical properties of chemically deposited tin sulfide thin films

Low-cost kesterite (CZTS) bilayers as an effective hole-transport layer for perovskite solar cells

This study investigates the utility of Copper Zinc Tin Sulfide (CZTS) thin films as inorganic hole-transporting layers (HTLs) in low-temperature perovskite solar cells (PSCs). The primary goal is to improve power conversion efficiencies (PCE) in PSCs using CZTS thin films fabricated through solution-based methods, with CH3NH3PbI3 perovskite and ZnO serving as the light-absorbing and electron-transporting components, respectively. Precise control over CZTS thin film growth significantly influences the formation of uniform perovskite layers. The study underscores the importance of achieving dense ZnO films with suitable grain sizes to confirm consistent coverage of perovskite films, enabling efficient charge transport while reducing recombination at the CZTS/perovskite interface. Results reveal that CZTS/CZTS bilayers exhibit superior photoelectrochemical performance compared to conventional CZTS(A)/FTO and CZTS(B)/CZTS(A) configurations. Evaluation of water splitting performance demonstrates that the CZTS/CZTS bilayer photoelectrode achieves the maximum photocurrent density, reaching 12 mA/cm2 vs. Ag/AgCl, with an Incident Photon-to-Current Efficiency of 9 % at 400 nm and an applied potential of 0.4V vs. Ag/AgCl. The study comprehensively examines CZTS impact on PSC photovoltaic properties and stability, culminating in a high-performance device with a PCE potential of up to 7 %. This underscores the pivotal role of CZTS− perovskite contacts in determining PSC photovoltaic performance and highlights CZTS potential as a versatile HTM for various PSCs designs.

Photosensitivity reversal in solution-processed Copper Zinc Tin Sulphide/Cadmium Sulphide superstrate junction

Inverse photosensitivity is a sought-after property for the development of photonic devices and non-volatile memories with low power conversion. Herein, we report on the development of a superstrate-type thin film junction exhibiting inverse photosensitivity which does not involve the use of a pricy transparent conducting oxide layer, providing a method for engineering low-cost thin film devices. Sequential ionic layer adsorption reaction (SILAR) was used to grow Copper Zinc Tin Sulphide (CZTS) and Cadmium sulphide (CdS) large area thin film p-n diode junction. Uniform CZTS thin films with an area of ∼10 cm2 which were free of pin holes or voids could be deposited using an optimized SILAR process recipe. The grown CZTS films exhibited an electrical resistivity of 4.4 × 10−4 Ωm using silver (Ag) electrodes. CdS thin films were sub-sequentially grown over the CZTS layer to form a p-n junction. A knee voltage of 0.2 V in the device configuration “glass/CZTS/CdS/Ag” was observed in the current voltage characteristics. The as-prepared and the vacuum-annealed p-n junction exhibited negative photosensitivity of magnitude 0.21 and 0.16 respectively. The air-annealed device structure exhibited photosensitivity of 216.

Mixed phase formation of SnS-SnO2 on air-annealed thermally evaporated SnS thin films

The present study examined the influence of annealing temperature on structural, morphological, electrical, and optical properties of thermally evaporated tin sulfide (SnS) thin films. The annealing of the prepared thin films has been carried out in the ambient atmosphere at a temperature between 100 and 300 °C. Structural, Optical, and compositional investigation has been performed using various characterization techniques. The X-ray diffraction pattern exhibits the mixed phase of SnS-SnO2 for the annealed films, ascribed to the reaction of SnS with atmospheric oxygen. A band gap in the 1.7–1.94 eV range was estimated from the Tauc-plots for all the films under investigation. The stoichiometric composition ratio of Sn/S=1.0 was obtained for the as-evaporated films. However, it deviates from the air-annealed SnS thin films. The air-annealed SnS thin films exhibit resistivity, carrier concentration and mobility in the range of 5.03–17.7 Ω-cm, 1.48 × 1018 – 2.18 × 1018 cm−3, and 0.04–1.05 cm2/V-s, respectively. The acquired results from this study elucidate the phase conversion of SnS thin films annealed in an ambient atmosphere. The current study aims to find an optimal absorber layer to enhance photovoltaic device performance.

Transformations and Environmental Impacts of Copper Zinc Tin Sulfide Nanoparticles and Thin Films.

Quaternary chalcogenide copper zinc tin sulfide (CZTS) nanoparticles are used to make the p-type absorber layer in CZTS solar cells, which are considered more benign alternatives to those based on cadmium telluride (CdTe) and less expensive than copper indium gallium selenide. CZTS has an ideal band gap and a high absorption coefficient for solar radiation, making the nanoparticles an attractive option for photovoltaic cells. In this work, we explore the toxicity of CZTS nanoparticles using an environmentally relevant bacterial model Shewanella oneidensis MR-1. This study also focuses on understanding the stability of CZTS-based thin films and their direct interaction with bacterial cells. Bacterial cell viability, stability of nanoparticles and thin films, as well as mechanisms of toxicity were evaluated using various analytical tools. The CZTS nanoparticle suspensions show significant acute toxic effects on bacterial cells, but long-term (72 h) exposure of bacterial cells to CZTS-based thin films (made from nanoparticles) do not exhibit similar detrimental impacts on bacterial viability. This result is compelling because it suggests that CZTS nanomaterials will have minimal unintended toxicity as long as they are incorporated into a stable film structure.

Enhanced Thermoelectric Performance of Tin(II) Sulfide Thin Films Prepared by Aerosol Assisted Chemical Vapor Deposition.

Orthorhombic SnS exhibits excellent thermoelectric performance as a consequence its relatively high Seebeck coefficient and low thermal conductivity. In the present work, polycrystalline orthorhombic SnS thin films were prepared by aerosol-assisted chemical vapor deposition (AACVD) using the single source precursor dibutyl-bis(diethyldithiocarbamato)tin(IV) [Sn(C4H9)2(S2CN(C2H5)2)2]. We examined the effects of the processing parameters on the composition, microstructure, and electrical transport properties of the SnS films. Deposition temperature dominates charge transport; the room temperature electrical conductivity increased from 0.003 to 0.19 S·cm-1 as deposition temperature increased from 375 to 445 °C. Similarly, the maximum power factor (PF) increased with deposition temperature, reaching ∼0.22 μW·cm-1·K-2 at 570 K. The power factors for SnS films deposited by AACVD are higher than values from earlier work on SnS bulks and SnS/SnSe films at temperatures up to 520 K. The electronic structure and electrical transport properties of SnS were investigated using density-functional theory to provide an improved understanding of the materials performance. To the best of our knowledge, the thermal conductivity (κ) of SnS film was measured for the first time allowing the figure of merit (zT) for SnS film to be evaluated. A relatively low thermal conductivity of ∼0.41 W·m-1·K-1 was obtained at 550 K for SnS films deposited at 445 °C; the corresponding zT value was ∼0.026. The SnS films are good candidates for thermoelectric applications and AACVD is a promising technique for the preparation of high-performance thermoelectric films.