Sb2S3 Film Research Articles

Copper doping of Sb2S3: fabrication, properties, and photovoltaic application

Sb2S3 solar cells are lagging behind conventional thin-film solar cells such as silicon solar cells and cadmium telluride solar cells in the power conversion efficiency (PCE). One of the most prominent problems is that the carrier concentration of Sb2S3 is relatively low. In order to increase the carrier concentration, elemental Cu was doped into Sb2S3 film by radio-frequency (RF) magnetron sputtering. We proved that Cu was doped into Sb2S3 films and mainly anchored with sulfur in the form of copper chalcogenide species at the surface and grain boundaries of Sb2S3. The doping of Cu essentially affects the physical and electrical properties of RF-sputtered Sb2S3 films such as the optical band gap, crystallinity, chemical composition, morphology, and carrier concentration. Specially, the electronic carrier concentration is remarkably increased from 6.28 × 109 to 6.06 × 1010 cm−3 and the Fermi level is also significantly uplifted after prudent doping with Cu. Planar solar cells based on RF-sputtered Cu-doped Sb2S3 absorber deliver an increased PCE of 1.13% and show good stability. This research proves that doping of Cu is an alternative and effective way to improve the electronic property of Sb2S3 films and enhance the performance of Sb2S3 solar cells.

Annealing temperature impact on Sb2S3 solar cells prepared by spin-coating method

Antimony sulfide (Sb2S3) thin film was prepared by a simple spin-coating method to fabricate Sb2S3 based inorganic–organic heterojunction solar cells. Annealing temperature impact on the optical absorption and crystallization of Sb2S3 films was studied systematically. The crystallinity and absorption of the Sb2S3 film improved significantly when the annealing temperature increased from 200 °C to 300 °C leading to the power conversion efficiency of Sb2S3-based solar cells increased from 0.02% to 1.91%.

Effect of dipping time on the properties of Sb2S3/Si heterojunction prepared by chemical bath deposition

The effect of dipping time on the structural, optical and electrical properties of Sb2S3 film deposited on the glass and silicon substrates by chemical bath deposition technique was studied. The values of the optical energy gap determined from optical absorption were in the range 2–2.5 eV indicating good tunability of the film energy gap in the visible region. X-ray diffraction XRD result confirms that the all deposited films are crystalline in nature with orthorhombic phase and the reflection peak intensity was found to be decreased as dipping time increase. Scanning electron microscope SEM investigation reveals that the film morphology and grain size are depending on the dipping time. The film deposited at 3 min reveals a porous structure and spherical microcrystalline particles distributed over plate-like crystallites structure was observed for a film deposited at a longer time. The elemental analysis of the film as a function of dipping time was investigated using energy dispersive x-ray EDX. The Hall mobility of the film has increased from 2 to 4.75 cm2V−1 s−1 as dipping time increased from 3 to 9 min. It was found that the dipping time playing a vital role in controlling the figures of merit of n-Sb2S3/p-Si heterojunction photodetectors namely dark and illuminated current-voltage, responsivity and specific detectivity. Spectral responsivity findings show that the photodetectors have two peaks of response located at 500 and 700 nm. Energy band diagram of the Sb2S3/Si heterojunction was constructed.

Composition engineering of Sb2S3 film enabling high performance solar cells

Sb2S3 is a kind of stable light absorption materials with suitable band gap, promising for practical applications. Here we demonstrate that the engineering on the composition ratio enables significant improvement in the device performance. We found that the co-evaporation of sulfur or antimony with Sb2S3 is able to generate sulfur- or antimony-rich Sb2S3. This composition does not generate essential influence on the crystal structure, optical band and film formability, while the carrier concentration and transport dynamics are considerably changed. The device investigations show that sulfur-rich Sb2S3 film is favorable for efficient energy conversion, while antimony-rich Sb2S3 leads to greatly decreased device performance. With optimizations on the sulfur-rich Sb2S3 films, the final power conversion efficiency reaches 5.8%, which is the highest efficiency in thermal evaporation derived Sb2S3 solar cells.

Low-cost processed antimony sulfide nanocrystal photoanodes with increased efficiency and stability

Environmentally harmless Antimony sulfide (Sb2S3) photoanode introduced water splitting device have a great potential for producing hydrogen from its optical characteristic. However, fabrication of highly pure Sb2S3 film by solution process has been suppressed due to the presence of various sulfide antimony compounds while chemical synthesis process. Here, high phase purity and high crystallinity Sb2S3 nanocrystal was successfully fabricated by mechanical alloying method. The solvent free and simple fabrication process realized low manufacturing cost of Sb2S3 nanocrystal fabrication without environmental hazard. Optical characterization by XRD, XPS and Raman spectroscopy confirmed that Sb2S3 nanocrystal film has high phase purity with high crystallinity. Furthermore, observed SEM images shows that fabricated Sb2S3 nanocrystal based nanostructure has high thermal stability till 300 °C. Finally, nanostructured Sb2S3 photoanode introduced water splitting device presented a saturation photocurrent of 0.69 mA cm−2 at 1.9 V versus the reversible hydrogen electrode (RHE) in 0.5 M H2SO4 under 1-sun illumination, with high stability and Фsaved, NPAC value, 4.36%. High photocurrent of water splitting device is originated from enlarged surface area of Sb2S3 nanocrystal film and electrical conduction improvement due to thermal annealing which reduced imperfections between nanoparticles.

Fabrication of Sb2S3 thin films by sputtering and post-annealing for solar cells

The semiconductor antimony sulfide (Sb2S3) is a potential absorber materials for the top sub-cell of Si-based tandem solar cells because of its appropriate band-gap, simple binary composition, nontoxic elements, and long-term stability. In this study, polycrystalline Sb2S3 films were fabricated by post-annealing of radio frequency (RF) magnetron sputtered precursors using an Sb2S3 target. The effects of the post-annealing temperature and atmosphere on Sb2S3 film properties and device performances were investigated. A high-performance device having a 2.41% power conversion efficiency was obtained by making use of a uniform Sb2S3 absorber layer. This preliminary experimental study shows that Sb2S3 thin films could be used as top sub-cell absorber materials for third-generation high efficiency, stable, and environmentally friendly Sb2S3/Si tandem solar cells.

N-Type Doping of Sb2S3 Light-Harvesting Films Enabling High-Efficiency Planar Heterojunction Solar Cells.

Sb2S3 is a kind of new light-absorbing material possessing high stability in ambient environment, high absorption coefficient in the visible range, and abundant elemental storage. To improve the power conversion efficiency of Sb2S3-based solar cells, here we control the defect in Sb2S3 absorber films. It is found that the increase of sulfur vacancy is able to upgrade photovoltaic properties. With the increase in sulfur vacancy, the carrier concentrations are increased. This n-type doping gives rise to an upshift of the Fermi level of Sb2S3 so that the charge transport from Sb2S3 to the electron selection material becomes dynamically favorable. The introduction of ZnCl2 in film fabrication is also found to regulate the film growth for enhanced crystallinity. Finally, the photovoltaic parameters, short-circuit current density, open-circuit voltage, and the fill factor of the device based on the Sb2S3 film are all considerably enhanced, boosting the final power conversion efficiency from 5.15 to 6.35%. This efficiency is the highest value in planar heterojunction Sb2S3 solar cells and among the top values in all kinds of Sb2S3 solar cells. This research provides a fundamental understanding regarding the properties of Sb2S3 and a convenient approach for enhancing the performance of Sb2S3 solar cells.

Aqueous-Solution-Based Approach Towards Carbon-Free Sb2 S3 Films for High Efficiency Solar Cells.

Sb2 S3 is a new kind of photovoltaic material that is promising for practical application in solar cells owing to its suitable bandgap, earth-abundant elements, and excellent stability. Here, we report on an aqueous-solution-based approach for the synthesis of Sb2 S3 films from easily accessible Sb2 O3 as antimony source. In this reaction, 3-mercaptopropionic acid was applied as both solvent and sulfur precursor, aqueous ammonia was employed as a solvent. After simple annealing at a temperature as low as 270 °C, the spin-coated precursor solution can generate compact, flat, uniform, and well-crystallized Sb2 S3 film. Mechanistic study showed that the formation of Sb-complex with ammonium carboxylates leads to the successful dissolution of Sb2 O3 powder. A suitable annealing process was able to generate carbon-free Sb2 S3 films. Planar heterojunction solar cell based on the as-prepared Sb2 S3 film delivered a power conversion efficiency of 5.57 %, which is the highest efficiency of solution-processed planar heterojunction Sb2 S3 solar cells and a high value in all kinds of Sb2 S3 solar cells. This research provides a convenient approach for the fabrication of device-quality Sb2 S3 films, and highlights solution processing of carbon-free metal chalcogenide thin films as a suitable process for application in optoelectronic devices.

A novel in situ hydrothermal preparation route for Sb2S3 and its solar cell application

In this study, we reported a novel in situ hydrothermal approach for fabricating Sb2S3 films. Metal Sb films were first deposited on substrates using room-temperature radio frequency magnetron sputtering and then undergo an in situ transformation to Sb2S3 films through a novel low-temperature hydrothermal reaction. Characteristics of the obtained Sb2S3 films prepared by our method were investigated. Planar Sb2S3 solar cells utilizing in situ fabricated Sb2S3 film as absorber has also been fabricated and yielded a power conversion efficiency of 1.32%.

One pot synthesis of Sb2S3 nanocrystalline films through a PVP-assisted hydrothermal process

In this paper, nanocrystalline antimony sulfide (Sb2S3) thin films were prepared on a tin-doped indium oxide (ITO) substrate via a facile polyvinylpyrrolidone (PVP)-assisted hydrothermal method. The crystal structure, morphology and optical properties of the Sb2S3 films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–vis spectroscopy. Well-crystallized Sb2S3 films possessed a honeycomb-like morphology with a whole thickness of approximately 360 nm on the ITO substrate and had a band gap of 2.0 eV. The reaction parameters that influenced the formation of Sb2S3 films, such as reaction time, temperature and quantity of PVP were investigated. PVP was found to play an important role in the formation of the honeycomb-like Sb2S3 films. In the absence of PVP, only large aggregates formed on the ITO substrate. A possible growth mechanism of the Sb2S3 films has been proposed. Furthermore, the as-synthesized Sb2S3 film exhibited a photocurrent density of −0.025 mA cm−2 at 0 V (vs. RHE) in a neutral solution, close to that of the heated Sb2S3 film. A stability test demonstrated that the as-synthesized Sb2S3 film was stable in both neutral and acidic solutions. This investigation might provide a feasible method for preparing high-quality Sb2S3 films to be used in solar energy conversion.

Microstructural and Optical Properties of Sb2S3 Film Thermally Evaporated from Antimony Pentasulfide and Efficient Planar Solar Cells

Antimony sulfide (Sb2S3) thin film is a promising light absorber for solar cell application due to its suitable bandgap, high absorption coefficient, and non‐toxic constituents. However, thermally evaporated Sb2S3 thin films experience sulfur loss during evaporation and post‐annealing, which do harm to the film quality and the performance of the devices. In this work, for the first time Sb2S3 thin films are prepared by thermally evaporating antimony pentasulfide (Sb2S5) precursor. The thermal and microstructural properties of Sb2S3 and Sb2S5 precursors are studied and compared. The crystallization of the Sb2S3 film (S‐5) prepared from Sb2S5 precursor is inferior to that (S‐3) from Sb2S3 powder. And the annealed S‐5 film shows a larger bandgap of 1.69 eV than S‐3. However, compared with S‐3, planar S‐5 thin film solar cells in the configuration of glass/(SnO2:F) FTO/TiO2/Sb2S3/Spiro‐OMeTAD/Ag exhibit an apparently improved photovoltaic performance, with the best power conversion efficiency of 3.75% and high fill factor of 0.56, which is the highest efficiency of thermally evaporated planar Sb2S3 solar cell. The capacitance–voltage (C–V) measurement indicates that this might come from the higher C–V derived space‐charge density in S‐5. This work offers a new method to prepare Sb2S3 thin films for efficient solar cells.

Postsurface Selenization for High Performance Sb2S3 Planar Thin Film Solar Cells

Sb2S3 has attracted great research interest very recently as a promising absorber material for thin film photovoltaics because of their unique optical and electrical properties, binary compound and easy synthesis. Sb2S3 planar solar cells from evaporation method without hole-transport layer (HTM) assistance suffer from sulfur deficit vacancy and high back contact barrier. Herein, we developed a postsurface selenization treatment to Sb2S3 thin film in order to improve the device performance. The XRD, Raman, and UV–vis spectra indicated the treated film kept the typical characters of Sb2S3. TEM/EELS mapping of treated Sb2S3 film revealed that only surface adjacent section was partly selenized and formed Sb2(SxSe1–x)3 alloy. In addition, XPS results further unfolded that there was trace selenium doping in the bulk of Sb2S3 film. The treated HTM-free Sb2S3 based solar cells were fabricated and an improved efficiency of 4.17% was obtained. The obtained VOC of 0.714 V was the highest and the power conversion ef...

A Novel Chemical Sensor Based on Sb2S3 Film for Highly Sensitive Detection of Hydrazine

AbstractThe Sb2S3 film on indium‐tin oxide (ITO) substrate has been used as an efficient electron transfer mediator for the fabrication of novel chemical sensor towards hydrazine, which is a diamine known as neurotoxin and carcinogen. Sb2S3 film is deposited on ITO substrate by drop‐casting process using Sb2S3 solution as precursor and possesses reticular structure with the morphology of uniform hollow hemispheres. The fabricated chemical sensor for selective detection of hydrazine displays a high sensitivity of 106.25 μA/(mM cm2) with a low detection limit of 0.5 μM and it also exhibits excellent reproducibility and stability in hydrazine detection.

Sb2S3 thickness-dependent lateral photovoltaic effect and time response observed in glass/FTO/CdS/Sb2S3/Au structure.

As an interesting one dimensional ribbon material, Sb2S3 has recently attracted much attention in recent years due to its exciting optical properties. However, Sb2S3-based photovoltaic or photoelectronic devices are still in research, and there are many things unknown to us and need to be well studied. In this work, the glass/FTO/CdS/Sb2S3/Au structures were successfully prepared with different Sb2S3 thicknesses, and the lateral photovoltaic effect (LPE) was firstly observed in this structure, suggesting its great potential in position sensitivity detectors (PSD). It is demonstrated that the crystallinity of Sb2S3 film increases, and Sb2S3 film tends to be vertical ribbon orientation with increasing thickness. Owing to the strong light absorption of the thicker Sb2S3 film and its one dimensional ribbon like crystal structure, the LPE in the glass/FTO/CdS/Sb2S3/Au structure improves with increasing Sb2S3 thickness from 350 nm to 800 nm, and the glass/FTO/CdS/Sb2S3(800 nm) structure exhibits an unprecedented performance with position sensitivity as large as 2230.4 mV/mm. Moreover, the time response of photovoltage was also firstly measured in this structure, it is observed that both the rise time and the fall time decrease with increasing thickness from 350 nm to 800 nm, and then increase quickly for 1100 nm film, further verifing that the Sb2S3 thickness-dependent LPE is strongly dependent on the carriers' longitudinal transport time. The very large LPE and the relatively fast response speed observed in the glass/FTO/CdS/Sb2S3(800 nm)/Au structure unveils its great potential applications in the optoelectronic detectors and also bring an insight that the suitable thickness is very crucial in Sb2S3-based devices.

Low-cost TiO2/Sb2(S, Se)3 heterojunction thin film solar cell fabricated by sol-gel and chemical bath deposition

Low cost TiO2/ Sb2(S, Se)3 heterojunction thin film solar cell are prepared successfully by using sol-gel and chemical bath deposition. At first, TiO2 thin film is prepared on the ITO-coated glass substrate by a simple sol-gel and dip-coating method. Subsequently, Sb2(S, Se)3 film is fabricated on TiO2 by selenizing the Sb2S3 film prepared by chemical bath deposition (CBD). The heat-treated process of TiO2 and Sb2(S, Se)3 films has been discussed, respectively. After being heat-treated at 550°C for TiO2 and 290°C for Sb2(S, Se)3 films, the photovoltaic devices are completed with the conductive graphite as electrode. The J-V characteristics of TiO2/ Sb2(S, Se)3 solar cell are measured and the open circuit voltage (Voc) of this cell is about 350mV.

Selenium‐Graded Sb2(S1−xSex)3 for Planar Heterojunction Solar Cell Delivering a Certified Power Conversion Efficiency of 5.71%

To efficiently convert solar energy into electricity at low cost with long‐term stability is one of the major tasks in solar cell research and applications. Antimony sulfide‐selenide [Sb2(S1−xSex)3] with a tunable bandgap in the range of 1.1–1.8 eV are considered promising photovoltaic materials due to their low‐toxicity, long‐term durability, and abundant element availability. Herein, selenium‐graded Sb2(S1−xSex)3 is synthesized through diffusion controlled solid‐state reaction between selenium and pre‐formed Sb2S3 film. In the device, sulfur‐rich Sb2(S1−xSex)3 with large bandgap leads to high voltage output, while narrow‐bandgap selenium‐rich Sb2(S1−xSex)3 expands spectral response toward longer wavelength. As a consequence, the device yields an open‐circuit voltage comparable to Sb2S3 solar cell, along with a significantly enhanced photocurrent density of 19.43 mA cm−2, finally delivering a certified power conversion efficiency of 5.71%, which is the highest certified value in planar heterojunction solar cells based on Sb2(S1−xSex)3. Initial stability examination shows that the device can maintain 88% efficiency after storing for 90 days in moderate humidity and ambient light irradiation. This investigation offers an effective strategy to the fabrication of composition‐graded Sb2(S1−xSex)3 for long‐term stable devices. The methodology may be extended for the fabrication of a broad class of composition‐graded metal sulfide/selenide for solar cell performance enhancement.

Efficient and stable TiO2/Sb2S3 planar solar cells from absorber crystallization and Se-atmosphere annealing

Inorganic Sb2S3 thin film solar cells show wide application prospects in low cost, non-toxicity and high stability solar cells comparing with well-developed CIGS, CdTe and organohalide perovskite materials. The present work successfully fabricated Sb2S3 film utilizing rapid thermal evaporation (RTE) method. By optimizing the crystal growth technique, smooth and non-pinhole Sb2S3 film was deposited on compact TiO2 substrate. The corresponding planar TiO2/Sb2S3 solar cells without hole transport material (HTM) assistance achieved an efficiency of 2.5%. To eliminate S-shape J-V curves and improve the fill factor, the as-deposited Sb2S3 film was further annealed in selenium atmosphere. The efficiency and fill factor of Se-atmosphere annealed Sb2S3 devices were improved to 3.2% and 55%, respectively. The device improvement mechanism of Se-annealing process were systematically illustrated by cryogenic measurements, impedance analysis and capacitance-voltage characterizations. The post-annealing could help to improve junction quality, passivate absorber defects and decrease back contact barrier. The Se-atmosphere annealed Sb2S3 devices could stand continuous one sun illumination for 400 h and the efficiency was almost the same. After storing in air for six months, the average efficiencies still hold more than 90% of initial value. The present developed environment-friendly stable devices and efficient treatment technique were expected to enrich the research of thin film solar cell.

A fast chemical approach towards Sb2S3 film with a large grain size for high-performance planar heterojunction solar cells.

A facile chemical method is developed for the fabrication of Sb2S3 film with a lateral grain size as large as ∼12 μm. A solar cell based on this Sb2S3 film achieves a power conversion efficiency of 4.3%, which is the highest value in solution processed planar heterojunction solar cells based on Sb2S3 film.

Efficient planar antimony sulfide thin film photovoltaics with large grain and preferential growth

Compact thin film of antimony sulfide (Sb2S3) as a promising absorber layer was obtained by rapid thermal evaporation (RTE) rather than conventional chemical bath deposition or atomic layer deposition based methods. The systematical characterizations of Sb2S3 film demonstrated the pure phase, void free and high crystallization. The large grain and preferential growth of Sb2S3 thin film were implemented by crystallization and cooling techniques, respectively. The corresponding devices were gradually optimized with a power conversion efficiency of ~3.5%, almost three times of planar devices fabricated by vacuum method. Both the non-oxide buffer layer (CdS layer) and free of hole transport layer enabled the high stability of the non-encapsulated planar devices. The high throughput and reliable RTE fabrication technique, environment-friendly and earth-abundant Sb2S3 materials, stable and superior device performances were expected to drive the research progress of Sb2S3 thin film photovoltaics.

A green and facile hydrothermal approach for the synthesis of high-quality semi-conducting Sb2S3 thin films

High-quality semi-conducting antimony sulfide (Sb2S3) thin films were directly deposited on the indium tin oxide (ITO) substrates by a green and facile one-step approach based on a hydrothermal reaction and post-annealing process without any assistance of complexing agents. The obtained Sb2S3 films possessed a relatively ideal S/Sb atomic ratio and a compact and continuous surface as the grain size of Sb2S3 was increased by high temperature annealing. The Sb2S3 film annealed at 450°C exhibited the improved optical and electrical performances, with a narrow band gap of 1.63eV, an electrical resistivity of 1.3×104Ωcm, a carrier concentration of 7.3×1013cm−3 and a carrier mobility of 6.4cm2V−1s−1. This environmentally friendly synthetic route is promising for the preparation of high-quality Sb2S3 films to be used as absorber layer materials for high-performance solar cells.