Sb2S3 Layer Research Articles

On the performance and thermal stability of solar cell based on CIGS-Sb2S3 combination with >35% power conversion efficiency

This study presents a solar cell design utilizing a CIGS (copper-indium-gallium-selenide) absorber and Sb2S3 (antimony trisulfide) back surface field (BSF) layers, targeting high photovoltaic (PV) performance with an emphasis on minimum possible effect of ambient temperature. We simulated a solar cell design consisting of zinc oxide, surface defect layer, zinc sulfide, CIGS layer, and an Sb2S3 layer using SCAPS-1D software. Our findings indicate that 200 nm Sb2S3 layer and a 1600 nm CIGS layer is the preferred combination for achieving high PV performance and appropriate J-V characteristics of the proposed solar cell. For this design, the achieved values of VOC (open circuit voltage), JSC (short circuit current density), PCE (power conversion efficiency), and fill factor (FF) are 1.069V, 42.08 mA/cm2, 35.94%, and 80.31%, respectively. The PV performance of the proposed solar cell is substantially better than the solar cell design without BSF layer as well as recently reported (2023-24) solar cell designs. This study further examines the impact of elevated ambient temperatures (295–360 K) on the PV performance. Our simulation results show that operating the proposed solar cell at moderately elevated temperatures is not a significant issue owing to small power temperature coefficient (-0.034% per K), which is comparable to that of commercially available solar cells. These findings are expected to contribute to the ongoing advancement of PV solar cells, aiming for higher PCE and improved stability, including thermal stability. Proposed solar cell with low PTC and high PCE can be suitable for space applications where temperature fluctuation is severe, as well as in tropical areas.

Effect of Sb2S3 sacrificial layer thickness on structural, optical and electrical properties of CuSbS2 films and investigation of diode parameters of CuSbS2/CdS heterojunctions

The ternary copper chalcogenides CuSbS2 (CAS) is found to have appealing optical and photovoltaic properties to be used as absorber layer in thin film solar cells. However, the difficulty to grow good quality CuSbS2 layer of micrometer thickness by chemical bath deposition method holds a big challenge. In this work, we reported the effect of incorporating Sb2S3 sacrificial layer of different thickness on structural, optical and electrical properties of CAS films. The X-ray diffraction results and Raman spectroscopic analysis confirm the formation of single-phase orthorhombic crystal structure for CuSbS2. The increase of Sb content in CAS films with the increase in deposition time of Sb2S3 layer has been reflected in the change in relative intensity ratio of characteristic Raman peaks as well as in diffraction peak profiles. The magnitude of defect states in terms of Urbach energy is decreased drastically by increasing Sb percentage in the films. A clear improvement in electrical properties of CAS films is observed with the decrease in Cu/Sb ratio. The carrier density is increased by one order of magnitude from 1016 to 1017 cm−3 and hole mobility increases from 1.14 to 4.87 cm2/Vs. The impact of Sb concentration on Scottky diode parameters of CAS/CdS heterojunction was studied by using thermionic emission model. Both the ideality factor and series resistance are decreased with the increase in Sb content. The J-V measurements reveal that the integration of Sb2S3 sacrificial layer improves the PV parameters such as fill factor, open circuit voltage, photocurrent and efficiency. The overall improvement in diode parameters can be ascribed to decrease in defect states, better film quality, absorber layer thickness and improved stoichiometry of CAS films.

Boosting conversion efficiency by bandgap engineering of ecofriendly antimony trisulfide indoor photovoltaics via a modeling approach

With the exponential growth of the Internet of Things (IoT), indoor photovoltaics (IPVs) have emerged as a pivotal technology for powering low-power devices, drawing heightened interest due to their adaptability to indoor environments. The Photovoltaic Conversion Efficiency (PCE) of IPV cells is critically dependent on their ability to match the indoor spectrum with the device's response characteristics. In this realm, Antimony Trisulfide (Sb2S3), characterized by its wide bandgap and high absorption coefficient, emerges as a promising candidate for low-light applications. Our study focuses on the modeling and numerical analysis of Sb2S3 thin-film IPV cells by wxAMPS software, aiming to refine both the device structure and its photoelectric performance for effective indoor light harvesting. In a strategic shift from conventional CdS materials, we utilized SnO2—known for its high transmissivity, non-toxicity, and wide bandgap—as the electron transport layer (ETL) in Sb2S3 IPV cells. This substitution notably enhanced the short-wave response, elevating the spectral response from 45 % to 80 % at 400 nm. Additionally, we introduced a bandgap-tunable ZnOS buffer layer. This innovation proved instrumental in rectifying the band alignment mismatch between SnO2 and Sb2S3 layer, thereby optimizing interfacial electron transport properties. The integration of the ZnOS buffer layer effectively improved the fill factor from 40.0 % to 64.7 % of the Sb2S3 IPV cell by solving the band mismatch problem. The resulting optimized Sb2S3 IPV cell demonstrated exceptional response characteristics across the full visible spectrum (400–750 nm) and showed notable photoelectric performance under both fluorescent lamps (FLs) and light-emitting diodes (LEDs). Moreover, a detailed analysis was conducted on the performance differences of the device under indoor light sources compared to solar spectrum conditions, along with the underlying mechanisms. Finally, the Sb2S3 IPV cell achieved a peak theoretical efficiency of 46.25 % under cold white FL lighting, a testament to the optimal match between the device structure and this specific emission power spectrum. This modeling research not only underscores the feasibility of employing antimony-based photovoltaic technologies in indoor settings but also offers theoretical guidance for further advancements in this domain.

Tunable Near-Infrared Transparent Bands Based on Cascaded Fabry–Perot Cavities Containing Phase Change Materials

In this paper, we construct a near-infrared Fabry–Perot cavity composed of two sodium (Na) layers and an antimony trisulfide (Sb2S3) layer. By cascading two Fabry–Perot cavities, the transmittance peak splits into two transmittance peaks due to the coupling between two Fabry–Perot modes. We utilize a coupled oscillator model to describe the mode coupling and obtain a Rabi splitting of 60.0 meV. By cascading four Fabry–Perot cavities, the transmittance peak splits into four transmittance peaks, leading to a near-infrared transparent band. The near-infrared transparent band can be flexibly tuned by the crystalline fraction of the Sb2S3 layers. In addition, the effects of the layer thickness and incident angle on the near-infrared transparent band and the mode coupling are investigated. As the thickness of the Na layer increases, the coupling strength between the Fabry–Perot modes becomes weaker, leading to a narrower transparent band. As the thickness of the Sb2S3 layer increases, the round-trip propagating of the Sb2S3 layer increases, leading to the redshift of the transparent band. As the incident angle increases, the round-trip propagating of the Sb2S3 layer decreases, leading to the blueshift of the transparent band. This work not only provides a viable route to achieving tunable near-infrared transparent bands, but also possesses potential applications in high-performance display, filtering, and sensing.

Designing Atomic Interface in Sb2S3/CdS Heterojunction for Efficient Solar Water Splitting.

In the emerging Sb2S3-based solar energy conversion devices, a CdS buffer layer prepared by chemical bath deposition is commonly used to improve the separation of photogenerated electron-hole pairs. However, the cation diffusion at the Sb2S3/CdS interface induces detrimental defects but is often overlooked. Designing a stable interface in the Sb2S3/CdS heterojunction is essential to achieve high solar energy conversion efficiency. As a proof of concept, this study reports that the modification of the Sb2S3/CdS heterojunction with an ultrathin Al2O3 interlayer effectively suppresses the interfacial defects by preventing the diffusion of Cd2+ cations into the Sb2S3 layer. As a result, a water-splitting photocathode based on Ag:Sb2S3/Al2O3/CdS heterojunction achieves a significantly improved half-cell solar-to-hydrogen efficiency of 2.78% in a neutral electrolyte, as compared to 1.66% for the control Ag:Sb2S3/CdS device. This work demonstrates the importance of designing atomic interfaces and may provide a guideline for the fabrication of high-performance stibnite-type semiconductor-based solar energy conversion devices.

Improvement of the photoelectrical properties of chemical bath-deposited Sb2S3 thin films with low copper doping

The chemical bath deposition method was used to prepare Cu-doped Sb2S3 thin films from complexes of Cu and Sb with triethanolamine. The as-deposited films with orange coloration had good adherence to the substrate. After an annealing treatment at 300 °C for 30 min in an Ar atmosphere, the resulting films acquired a brown color and exhibited the orthorhombic phase of Sb2S3 with the preferential growth of [hk0] grains. The Sb2S3 films were formed by rod-shaped nanoparticles, while the insertion of Cu ions in Sb2S3 promoted the formation of ribbon-like structures. The analysis of optical properties indicated the narrowing of bandgap energy from 1.9 to 1.8 eV due to the presence of Cu ions. In addition, the photoconductivity of the films increased from 8.3 × 10–6 to 30.5 × 10–6 Ω−1cm−1, while the photosensitivity factor was enhanced by more than 3 times. The performance of photovoltaic devices based on CdS/Sb2S3 and CdS/Cu:Sb2S3 heterojunctions were investigated. Compared with the device using a Sb2S3 layer, the one using a Cu-doped Sb2S3 layer exhibited an increase in open circuit voltage from 118.2 to 205 mV, short circuit current density from 0.14 to 0.34 mA/cm2 and conversion efficiency from 0.02 to 0.12%. The best performance was obtained by a photovoltaic device with a 500 nm Cu-doped Sb2S3 layer reaching an open circuit voltage of 226 mV, a short circuit current density of 0.94 mA/cm2 and conversion efficiency of 0.32%.

Sputtering of Molybdenum as a Promising Back Electrode Candidate for Superstrate Structured Sb2 S3 Solar Cells.

Sb2 S3 is rapidly developed as light absorber material for solar cells due to its excellent photoelectric properties. However, the use of the organic hole transport layer of Spiro-OMeTAD and gold (Au) in Sb2 S3 solar cells imposes serious problems in stability and cost. In this work, low-cost molybdenum (Mo) prepared by magnetron sputtering is demonstrated to serve as a back electrode in superstrate structured Sb2 S3 solar cells for the first time. And a multifunctional layer of Se is inserted between Sb2 S3 /Mo interface by evaporation, which plays vital roles as: i) soft loading of high-energy Mo particles with the help of cottonlike-Se layer; ii) formation of surficial Sb2 Se3 on Sb2 S3 layer, and then reducing hole transportation barrier. To further alleviate the roll-over effect, a pre-selenide Mo target and consequentially form a MoSe2 is skillfully sputtered, which is expected to manipulate the band alignment and render an enhanced holes extraction. Impressively, the device with an optimized Mo electrode achieves an efficiency of 5.1%, which is one of the highest values among non-noble metal electrode based Sb2 S3 solar cells. This work sheds light on the potential development of low-cost metal electrodes for superstrate Sb2 S3 devices by carefully designing the back contact interface.

Synthesis of Sb2S3 nanosphere layer by chemical bath deposition for the photocatalytic degradation of methylene blue dye.

An antimony tri-sulfide Sb2S3 nanosphere photocatalyst was effectively deposited utilizing sodium thiosulfate and antimony chloride as the starting precursors in a chemical bath deposition process. This approach is appropriate for the large-area depositions of Sb2S3 at low deposition temperatures without the sulfurization process since it is based on the hydrolytic decomposition of starting compounds in aqueous solution. X-ray diffraction patterns and Raman spectroscopy analysis revealed the formation of amorphous Sb2S3 layers. The scanning electron microscopy images revealed that the deposited Sb2S3 has integrated small nanospheres into sub-microspheres with a significant surface area, resulting in increased photocatalytic activity. The optical direct bandgap of the Sb2S3 layer was estimated to be about 2.53 eV, making amorphous Sb2S3 appropriate for the photodegradation of organic pollutants in the presence of solar light. The possibility of using the prepared Sb2S3 layer in the photodegradation of methylene blue aqueous solutions was investigated. The degradation of methylene blue dye was performed to evaluate the photocatalytic property of Sb2S3 under visible light. The amorphous Sb2S3 exhibited photocatalytic activity for the decolorization of methylene blue solution under visible light. The mechanism for the photocatalytic degradation of methylene blue has been proposed. Our results suggest that the amorphous Sb2S3 nanospheres are valuable material for addressing environmental remediation issues.

Enhancement of the photoconversion efficiency of Sb2S3 based solar cell by overall optimization of electron transport, light harvesting and hole transport layers

In thin-film photovoltaic, Sb2S3 is a leading absorber material due to its broad-band optical response and excellent electrical properties, with the highest reported efficiency in the planar Sb2S3 configuration being 8 %. By simulations, optimized parameters for each component of the n-i-p FTO/ETL/Sb2S3/HTL/Au planar heterojunction device, as well as a photoconversion efficiency (PCE-η) of 28.64 % under an AM 1.5G spectral irradiance, have been predicted. In this report, we systematically optimized the electron transport layer (ETL), light harvesting layer (Sb2S3), and hole transport layer (HTL) separately based on theoretically predicted values in order to understand the effect of each component and optimize solar cell performance. The optimized results showed that simply optimizing the ETL, Sb2S3 layer, and HTL resulted in achieving the efficiency ∼4.11 % and to achieve the theoretically predicted device performance, a precise control of intrinsically formed traps, the presence of surface defect states, and lattice dislocations in Sb2S3, are important as these factors are found to be the main factors that enhance charge carrier recombination, slow charge transfer across the interface, and charge carrier mobility.

Visible light metasurface for adaptive photodetection

Semiconductor-based sub-wavelength metasurfaces are promising device platforms for the realization of optically thick and electrically thin photodetectors. Strong light–matter interactions in ultrathin film regions provide an opportunity to achieve near-unity absorption in dimensions comparable with carrier diffusion length and this, in turn, leads to an efficient collection of photogenerated carriers. Moreover, the use of phase change materials can provide real-time active tuning of optical responses of metasurface-based devices. In the first part of this paper, a tunable color filtering device is demonstrated using a metasurface design made of sub-wavelength antimony trisulphide (Sb2S3) grating placed on top of a continuous silver layer. Four distinct optical states can be acquired upon (a) the changes in the incident light polarization and (b) the phase transitions of Sb2S3. Numerical simulations and theoretical modeling data show that Fabry–Perot resonances are the driving phenomena when the proposed design is normally illuminated by an electromagnetic field with transverse electric polarization. In contrast, surface plasmon resonances are excited in transverse magnetic polarization. Furthermore, it is shown that the resonance wavelengths of the proposed design can be dynamically tuned using the geometrical parameters. Later, in the second part of the paper, adaptive photodetection is designed by integrating a nm Sb2S3 layer as a collection layer into the structure. The proposed metasurface design provides light–matter interaction in the Sb2S3 layer and maximizes the photogenerated carriers’ collection efficiency. The optically thick and electrically thin adaptive photodetection offers an opportunity to design efficient active optoelectronic and photonic devices.

Reconfigurable InP waveguide components using the Sb2S3 phase change material

Reconfigurable waveguide components are promising building blocks for photonic neural networks and as an optical analogue to field-programmable gate arrays. By changing the effective index of the waveguide, reconfigurable waveguide components can achieve on-chip light routing and modulation. In this paper, we design and demonstrate an Sb2S3-reconfigurable InP membrane Mach–Zehnder interferometer (MZI) on a silicon substrate. Sb2S3, which has tunable refractive index and low absorption in the near-infrared spectrum, was patterned on the InP waveguide MZIs to make an optical switch in the telecoms conventional-band. By laser induced crystallisation of the Sb2S3, it was possible to control interference in the MZI and achieve 18 dB on/off switching at 1540 nm. Laser reamorphisation and reversible switching of the Sb2S3 layer resulted in damage to the waveguide structure. However, simulations show that transition metal di-chalcogenide two-dimensional crystal layers can act as efficient thermal barriers that prevent thermal damage to the waveguide during laser amorphisation. Therefore, combining Sb2S3 with InP waveguides seems to be a feasible approach to achieve low-loss reprogrammable waveguide components for on-chip photonics routing and neural networks.

Numerical analysis and design of high performance HTL-free antimony sulfide solar cells by SCAPS-1D

Among the various absorbers encountered in thin film solar cells (TFSCs), antimony sulfide (Sb2S3) is considered a suitable candidate as it is a non-toxic and earth-abundant besides its high absorption coefficient. However, some critical issues cause its poor photovoltaic performance. These include unoptimized Sb2S3 layer, interface recombination and cell properties like the ineffective carrier collection and transport. To enhance the power conversion efficiency (PCE) of Sb2S3 solar cell, we suggest some design guidelines by employing device simulation. First, a calibration step is performed vs an experimental arrangement consists of FTO/TiO2/Sb2S3/Spiro-OMeTAD/Au to validate the simulation model. Next, as the organic hole transport material (HTM) often has poor long-term operation stability and demands high-cost fabrication processes, an HTL-free cell is proposed and designed by investigating the impact of the main technological and physical parameters. In the first step in the design of the HTL-free cell, we provide an affinity engineering methodology to tune the conduction band offset between the electron transport layer (ETL) and the absorber. Based on this approach, the most appropriate electron transport material (ETM) is chosen that fulfills the maximum efficiency. Then, an optimization routine is performed to select the most appropriate design parameters and the PCE of the optimized case is found to be about 22%. All simulations, carried out in this work, are performed by SCAPS-1D device simulator under AM1.5G illumination and 300 K temperature.

Towards high-efficiency planar heterojunction antimony sulfide solar cells

Recently, antimony sulfide (Sb2S3) based solar cells have received substantial attention, however their practical efficiency is far from ideal. Therefore, it is critical to provide numerical simulation on the devices, giving possible avenues to improve the performance. A planar heterojunction solar cell with a structure of FTO/electron transport layer (ETL)/Sb2S3/Cu2O/Au was investigated theoretically by Solar Cell Capacitance Simulator (SCAPS). The influence of different ETLs (CdS, TiO2, ZnO) and Cu2O layer has been firstly analyzed, and our results show that the best ETL is TiO2, and the device efficiency can be significantly increased when Cu2O is used as a hole transport layer (HTL). Then, the electron affinity of TiO2, Sb2S3 layer thickness, defect density, and metal work function on device performance have also been studied systematically. The best electron affinity of TiO2 is 3.6 eV, because a small positive conduction band offset (ΔEC = 0.1 eV) at the TiO2/Sb2S3 interface can be formed, enhancing carrier transport, and consequently, improving the device performance. Further, the optimal thickness for Sb2S3 layer is 200 nm when the defect density of the Sb2S3 layer is 1015 cm−3. To achieve ideal performance, the defect densities in the Sb2S3 layer and at the Sb2S3 interfaces should be as low as 1012 cm−3 and 2 × 1015 cm−2, respectively. In addition, the work function of the metal electrode larger than 4.9 eV is beneficial to device performance. Finally, a Sb2S3 solar cell with the conversion efficiency of 21.43% can be achieved after optimization, which performance is close to the conventional thin film solar cells. Our simulation results suggest the potential of Sb2S3 solar cells.

Sb2S3 thin films by ultrasonic spray pyrolysis of antimony ethyl xanthate

Synthesis of antimony chalcogenides, especially Sb2S3, by facile and area scalable in-air chemical methods, such as spray pyrolysis, from cost-effective chemicals is certain to accelerate development of the related thin film solar cell technology. In this study, antimony ethyl xanthate, a scarcely studied halogenide-free precursor, is proven to be suitable for the deposition of conformal phase pure crystalline Sb2S3 thin films via ultrasonic spray pyrolysis in air by a two-step process. First, a solution of antimony ethyl xanthate with thiourea in a molar ratio of 1/3, or with thioacetamide in a molar ratio of 1/10 was sprayed onto a glass/ITO/TiO2 substrate by ultrasonic spray pyrolysis at 215°C to yield amorphous phase pure Sb2S3 thin films. Second, performing post-growth heat treatment in vacuum at 225°C, was the key to produce phase pure conformal thin films of crystalline Sb2S3 (Eg 1.8 eV) with S/Sb atomic ratio of 1.46 by using thiourea, and 1.41 by using thioacetamide, respectively. Spraying solutions of antimony ethyl xanthate at ≥135°C resulted in the formation of the Sb2O3 phase. Adding thiourea or thioacetamide to the spray solution prevented the oxidation of the growing Sb2S3 layer during deposition at 135°C, 165°C, and 215°C. The suppressed oxidation of Sb2S3 layers is attributed to the liquid state of thiourea and thioacetamide in these conditions.

Sb2S3 surface modification for improved photoelectrochemical water splitting performance of BiVO4 photoanode

A fabrication of Sb2S3 layer as surface modification on pyramidal BiVO4 film is realized to improve photoelectrochemical (PEC) performance of BiVO4 photoanode. The Sb2S3-modified BiVO4 film exhibits an increased photocurrent density of 1.1 mA / cm2 at 1.23 V versus reversible hydrogen electrode and a negative shift of onset potential. Further, the negative shift of flat band potential demonstrates that the role of Sb2S3 surface modification is to suppress surface recombination, and thus increased surface separation and hole transfer efficiency are also achieved for the Sb2S3-modified BiVO4 photoanode. Accordingly, the Sb2S3 surface modification enhances surface water oxidation kinetics for the BiVO4 photoanode, resulting in improved PEC performance. These findings inspire further application of Sb2S3 into a PEC water splitting system.

Design and simulation of Sb2S3 solar cells based on monolayer graphene as electron transport layer

In Sb2S3 solar cells, the p-n junction are generally formed by combination of p-type Sb2S3 absorber layer and n-type materials, such as CdS and TiO2. In this study, the design and simulation of the Sb2S3 solar cells with graphene as electron transport layer were performed. The device performance parameters with respect to the electron affinity of monolayer graphene, the doping concentration, thickness and bulk defect density of Sb2S3 layer were examined and optimized. The simulation results revealed that the performance of Sb2S3 solar cells could be improved by using a monolayer graphene with lower value of electron affinity. The optimum doping concentration of Sb2S3 absorber layer was found to be 1017 cm−3. Also, the optimum Sb2S3 absorber layer thickness was found to be 0.7 μm when the bulk defect density and the corresponding carrier diffusion length were 1015 cm−3 and 1.6 μm, respectively. According to the optimum values of different variables, the conversion efficiency of the Sb2S3 solar cells could be achieved as high as 23.30%. These results showed that the monolayer graphene could be served as an efficient and inexpensive electron transport layer.

Numerical simulation and performance optimization of Sb2S3 solar cell with a hole transport layer

Abstract Antimony sulfide (Sb2S3) solar cell is considered to be an emerging photovoltaic device technology. However, the conversion efficiency of Sb2S3 solar cell remains limited to lower than 8%. To boost the conversion efficiency, a device structure consists of FTO/ZnS/Sb2S3/Cu2O/Au was proposed and the device photovoltaic performance has been numerical simulated by wxAMPS. The initial values of bulk defect density in Sb2S3 layer and interface defect density at ZnS/Sb2S3 and Sb2S3/Cu2O interfaces are set to be 1016 cm−3, 1010 cm−2 and 1010 cm−2, respectively. The conversion efficiency increases from 6.24% to 16.65% by incorporating a Cu2O layer into the solar cell. The influence of Sb2S3 bulk material quality on device photovoltaic performance was also analyzed. It is important to note that a proper higher carrier diffusion length than the thickness of Sb2S3 layer should be guaranteed to facilitate the conversion of photogenerated electron-hole pairs to photogenerated current. It is feasible to achieve a value of 1015 cm−3 for bulk defect density in Sb2S3 layer (corresponding diffusion length is calculated to 1.6 μm) in further experimental work, then the optimized conversion efficiency of 21.99% at an optimized Sb2S3 layer thickness of 0.8 μm could be arrived. Furthermore, the influence of interface defects at ZnS/Sb2S3 and Sb2S3/Cu2O interfaces on device photovoltaic performance were also analyzed. It is feasible to achieve a value of 109 cm−2 for interface defect density at ZnS/Sb2S3 and Sb2S3/Cu2O interfaces and a best conversion efficiency of 22.78% can be obtained.

Semitransparent Sb2S3 thin film solar cells by ultrasonic spray pyrolysis for use in solar windows.

The integration of photovoltaic (PV) solar energy in zero-energy buildings requires durable and efficient solar windows composed of lightweight and semitransparent thin film solar cells. Inorganic materials with a high optical absorption coefficient, such as Sb2S3 (>105 cm−1 at 450 nm), offer semitransparency, appreciable efficiency, and long-term durability at low cost. Oxide-free throughout the Sb2S3 layer thickness, as confirmed by combined studies of energy dispersive X-ray spectroscopy and synchrotron soft X-ray emission spectroscopy, semitransparent Sb2S3 thin films can be rapidly grown in air by the area-scalable ultrasonic spray pyrolysis method. Integrated into a ITO/TiO2/Sb2S3/P3HT/Au solar cell, a power conversion efficiency (PCE) of 5.5% at air mass 1.5 global (AM1.5G) is achieved, which is a record among spray-deposited Sb2S3 solar cells. An average visible transparency (AVT) of 26% of the back-contact-less ITO/TiO2/Sb2S3 solar cell stack in the wavelength range of 380–740 nm is attained by tuning the Sb2S3 absorber thickness to 100 nm. In scale-up from mm2 to cm2 areas, the Sb2S3 hybrid solar cells show a decrease in efficiency of only 3.2% for an 88 mm2 Sb2S3 solar cell, which retains 70% relative efficiency after one year of non-encapsulated storage. A cell with a PCE of 3.9% at 1 sun shows a PCE of 7.4% at 0.1 sun, attesting to the applicability of these solar cells for light harvesting under cloud cover.

Preferentially oriented large antimony trisulfide single-crystalline cuboids grown on polycrystalline titania film for solar cells

Photovoltaic conversion of solar energy into electricity is an alternative way to use renewable energy for sustainable energy production. The great demand of low-cost and efficient solar cells inspires research on solution-processable light-harvesting materials. Antimony trisulfide (Sb2S3) is a promising light-harvester for photovoltaic purposes. Here we report on the in situ grown monolayer of preferentially oriented, large Sb2S3 single-crystalline cuboids on a polycrystalline titania (TiO2) nanoparticle film. A facile, oriented seed-assisted solution-processing method is used, providing the Sb2S3/TiO2-based bulk/nano-planar heterojunction with a preferred structure for efficient planar solar cells. An orientation-competing-epitaxial nucleation/growth mechanism is proposed for understanding the growth of the Sb2S3 single-crystalline cuboids. With an organic hole transporting material, the stable solar cell of the heterojunction yields a power conversion efficiency of 5.15% (certified as 5.12%). It is found that the [221]-oriented Sb2S3 cuboids provide highly effective charge transport channels inside the Sb2S3 layer.

Enhanced performance of Sb2S3 mesoscopic sensitized solar cells employing TiO2:Nb compact layer

This paper reports on the enhancement of charge transport and recombination by niobium doped compact layers of TiO2 in a solar cell with Sb2S3 absorber layer by characterizing both thin films of TiO2:Nb and working solar cell devices with the layer stack FTO/cp-TiO2:Nb/mp-TiO2/Sb2S3/P3HT/MoOx/Ag. The electron transport layers of TiO2 doped with 0.14 and 0.27 at.% Nb were prepared by spin coating and have no structural change as determined from the analysis of GIXRD spectra. SEM images show thin pin hole free layers of the cp-TiO2:Nb on FTO crystals that are agglomerates of particles. Analysis of the current–voltage curves of the solar cells with Sb2S3 as the absorber material showed increased short-circuit current, fill factor and power conversion efficiency from 1.3 to 1.7%. The enhancement of the device performance is attributed to substitution of Ti ions with Nb ions in the TiO2 resulting in a change in the band alignment of the solar cells with Nb content. This results in increase in charge recombination resistance in the Sb2S3 layer as determined from the analysis of the impedance spectroscopy measurements.