Antimony Chalcogenides Research Articles

Perspective of environmentally friendly antimony selenide-based solar cell

Antimony selenide has been intensively investigated as an interesting alternative for solar cell absorbers due to its excellent physical properties. Owing to the remarkable advancements in the last several decades, chemical and physics methods have improved the power conversion efficiency of antimony selenide solar cells by over 10%, almost at the level needed for industrial applications. In this perspective, we have outlined the issues and challenges these antimony chalcogenides face in photoelectric applications. We have proposed some feasible suggestions for improving its performance and applications in solar cells and other optoelectronic devices.

A Review on Suppressing Nonradiative Recombination Losses in Antimony Chalcogenide Thin‐Film Solar Cell

Antimony chalcogenide solar cells have captured considerable attention in recent years with an efficiency of over 10%, due to their use of Earth‐abundant materials and superior physical characteristics. Despite these achievements, significant nonradiative recombination processes within these solar cells present a substantial obstacle to further efficiency improvements. Therefore, this review delves into the primary mechanisms responsible for nonradiative recombination losses in antimony chalcogenide solar cells. Additionally, the latest advancements in addressing these losses are summarized. Finally, potential directions for future research efforts aimed at reducing nonrecombination losses and enhancing the overall performance of these devices are outlined.

The preferential orientation controlling for efficient Sb2S3 and low Se content Sb2SeyS3-y indoor photovoltaics

Sb2S3 is a promising absorber material for indoor photovoltaics due to the appropriate direct bandgap of 1.75 eV, high element abundance, low toxicity, stability, and single phase. Considering the indoor lighting irradiance is very low and the resulting carrier numbers are relatively less and Sb2S3 is quasi-one-dimensional crystal structure, the preferential orientation controlling of Sb2S3 is very important to improve the power conversion efficiency (PCE) of Sb2S3 indoor photovoltaics. Herein, Sb2S3 and low Se content Sb2SeyS3-y films are prepared by chemical bath deposition and the preferential orientation of Sb2S3 films is controlled by introducing SbCl3 and selenourea in the growth solution. The uniformity of the S and Se distribution in low Se content Sb2SeyS3-y films is adjusted by introducing EDTA-2Na. Using the warm white LED with a color temperature of 3347 K and illuminance of 1000 lux, Sb2S3 and low Se content Sb2SeyS3-y indoor photovoltaics achieve the PCE of 16.58% for Sb2S3 and 17.62% for Sb2SeyS3-y, which is the highest PCE for antimony chalcogenide indoor photovoltaics. Therefore, the preferential orientation controlling by introducing SbCl3 and selenourea into the growth solution is an efficient strategy for fabricating high-efficiency Sb2S3 and low Se content Sb2SeyS3-y indoor photovoltaics.

Optimal Composition of the Sby(S1−x,Sex)3 Ternary Absorber for High Efficiency Solar Cells

Solar cells based on Sb2(S1−x,Sex)3 ternary compounds have shown the highest reported efficiency value compared to their Sb2Se3 and Sb2S3 counterparts in antimony chalcogenide technology. However, the reported record efficiencies for these new emergent solar cells are still well below the theoretical values according to their bandgap value or for the traditional solar cells in the thin film technology. This article presents an analysis regarding the optimal composition that guarantees an increase in efficiency in the manufacture of Sby(S1−x,Sex)3 solar cells, as well as the proposal of a new synthesis method that allows obtaining the ternary compound with the calculated optimal composition. From theoretical considerations, a composition of Sb1.85(S0.63,Se0.42)3 is obtained. This composition is equivalent to optimal values Se/(S + Se) = 0.4 and Sb/(S + Se) = 0.88. The results of the new proposed synthesis method are presented and discussed.

A novel Se-diffused selenization strategy to suppress bulk and interfacial defects in Sb2Se3 thin film solar cell

In recent years, vacuum-based deposition of antimony selenide (Sb2Se3) thin films has garnered significant attention owing to its easy and impurity-free fabrication, along with exceptional power conversion efficiency (PCE). However, the necessary post-selenization process comes with a shortcoming of instigating buried Sb2Se3/molybdenum (Mo) back-contact interface defects. This study introduces a novel Se-diffusion post-selenization technique to precisely regulate the selenium reaction atmosphere, preventing void formation on the Sb2Se3 thin film surface and maintaining film quality for enhanced device efficiency. An optimized selenization condition with a precise Se precursor film thickness led to obtaining highly crystalline, preferentially (hk1) oriented, and large-grained Sb2Se3 films. Furthermore, a meticulous Se diffusion in Sb2Se3 film reduced the inevitable MoSe2 layer thickness at the Mo surface, thereby enhancing the quality of the back contact interface. The Sb2Se3 solar cell that was selenized to optimal level showed significant enhancements, raising the fill factor from 40.06 % to 45.12 % and improving the device efficiency from 2.89 % to 3.57 %. Our newly developed selenization strategy establishes a successful approach to regulate the Sb2Se3 film quality by addressing a crucial challenge in improving the efficiency of antimony chalcogenide solar cells.

Full optoelectronic simulation of all antimony chalcogenide thin film tandem solar cell: Design routes from 4-T to 2-T configuration

Antimony chalcogenide, as a newcomer to light harvesting materials, is regarded as an auspicious contender for incorporation as a photoactive layer in thin film tandem solar cells (TFTSCs). The current study introduces the design of all-antimony chalcogenide TFTSC comprised of an Sb2S3 (1.7 eV) front subcell and an Sb2Se3 (1.2 eV) rear subcell. The challenges to migrating from four-terminal (4-T) to two-terminal (2-T) designs are highlighted and possible solutions are proposed. To commence, a calibration procedure for the two subcells is conducted in alignment with experimental investigations. The benchmarked solar cells yield a power conversion efficiency (PCE) of 8.08 % for the upper subcell and 10.58 % for the lower subcell. Subsequently, upon integration of both subcells within the initial 4-T Sb2S3/Sb2Se3 TFTSC, the resultant PV cell attains a PCE of 12.27 %. Before transitioning it to a more efficient 2T tandem configuration, we explore alternative inorganic HTL materials to the Spiro-OMeTAD HTL to overcome its practical considerations. Cu2O is found to be the best HTL alternative to be included for both subcells. Upon stacking into the tandem structure, the combined cell exhibited an efficiency of 15.68 % and a notable Jsc of 16.23 mA/cm2. To further enhance the tandem performance, the device structure is optimized by engineering the CBO of two sub-cells and employing a double ETL design for the front sub-cell. At the considered current matching criterion, the tandem device PCE and Jsc are boosted to 27.86 % and 17.60 mA/cm2, respectively. Based on this full optoelectronic analysis, developed in the Silvaco TCAD environment, a 2-T all antimony chalcogenide tandem configuration can be realized and optimized, paving the way for future experimental endeavors.

Rational designing of derivatives of quinoline and iso-quinoline based hole transport materials for antimony chalcogenide and perovskite solar cells

For efficient and stable perovskite solar cells, small molecule hole transporting materials possessing robust hole mobility, hydrophobicity, and exceptional film fabrication are highly desirable. Herein, we have evaluated first-principle-based structural, electrochemical, photophysical, stability, and charge transport attributes of eight novel molecules (QT-M1 to QT-M4) and (IQT-M1-IQT-M4) attained via thiophene-spacer end-group acceptor engineering in quinoline and iso-quinoline based molecules Our results revealed that the freshly fabricated molecules showed effectual coherence in dispersion, transference, and excitation of charges, these are highly required attributes for ultrafast hole mobility. Drafted molecules showed exceptional band alignment along with the perovskite light-absorbing layer, which predicts effectual hole abstraction and transportation attributes. Comparatively, lower absorption in the visible region suggests the appropriate photophysical profile and the smaller hole reorganization energy values compared to the parent molecules estimate the ultrafast hole transport attributes. Moreover, the electron excitation states analysis predicts uniform charge transportation, reduced recombination losses, and greater charge dissociation. The high negative solvation-free energy of fabricated molecules exhibited easier film formation and processability. Overall, our results predict efficient strategies for optimizing solar cell devices with improved photophysical, electrochemical, and optoelectronic attributes.

Device engineering of Sb2X3 antimony chalcogenide for loss analysis and strategies for maximizing photovoltaic efficiency

Antimony chalcogenide (Sb2X3; X=S, Se) is reportedly stable in ambient open-air, abundant, and shows composition-dependent absorption tunability. We simulated the Sb2X3 device utilizing the reported optical and electrical properties to analyze the performance limiting factors and the extent of achievable performance. Initially, we benchmarked the simulated device with the experimental reported device. The VOC-temperature and VOC-illumination characterization of the benchmarked device revealed the contact issue responsible for the VOC deficit. The suboptimal device configuration is a major performance-limiting factor. Contact optimization and conduction band offset optimisation have improved efficiency to 14.86% and 20.45% in Sb2S3 and Sb2Se3, from their experimentally reported values of 7.5% and 9.2% respectively. The optimization of trap-assisted Shockley Read Hall (SRH) recombination in bulk and interface has improved efficiency to 19.43% and 26.13% in Sb2S3 and Sb2Se3, respectively. When extrinsic factors are optimised, such as resistance losses (series resistance as high as 2 Ωcm2 and shunt resistance as low as 1000 Ωcm2), efficiency increased to 20.03% and 26.82% for Sb2S3 and Sb2Se3, respectively. Finally, with ideal intrinsic recombination parameters (radiative and Auger recombination), efficiency improved to theoretical limits (corresponding to their band gap). The study highlights the possibility of immediate gain upon contact passivation in Sb2S3 and Sb2Se3.

Performance enhancement of Sb2(S,Se)3 solar cells through neodymium ion flow doping

Doping the light absorber layer of antimony chalcogenides with extrinsic ions is an effective approach for improving their photovoltaic quality. These dopant ions generally reside at positions other than the crystal lattice or form an alloy (e.g., AgSb(S,Se)3) with a poor device performance. Therefore, incorporating such ions into an antimony chalcogenide lattice such that there is a positive influence on device quality would be highly useful. Herein, doping of Nd3+ for Sb2(S,Se)3 is carried out via a modified hydrothermal deposition process. Notably, these ions are incorporated into the crystal lattice and migrate to the CdS/Sb2(S,Se)3 interface after doping, which are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. Nd3+ doping produces benign effects on the crystal orientation, film morphology, optoelectronic properties, and defect passivation of the Sb2(S,Se)3 films. Consequently, all the photoelectrical parameters of Sb2(S,Se)3 solar cells doped with Nd3+ are enhanced, delivering a remarkable efficiency of 8.24 %. Furthermore, the best device stored in air only shows a slight decrease in efficiency in the 2400-h aging test. Overall, this study provides an effective doping strategy to improve the photovoltaic quality of Sb2(S,Se)3 films.

High‐Index and Low‐Loss Topological Insulators for Mid‐Infrared Nanophotonics: Bismuth and Antimony Chalcogenides

AbstractTopological insulators generally have dielectric bulk and conductive surface states. Consequently, some of these materials are shown to support polaritonic modes at visible and THz frequencies. At the same time, the optical properties of topological insulators in the mid‐infrared (mid‐IR) remain poorly investigated. Here, near‐field imaging is employed to probe the mid‐IR response from the exfoliated flakes of bismuth (Bi)/selenide (Se)/telluride (Te)/antimony (Sb) crystals with varying stoichiometry – Bi2Se3, Bi2Te2Se, and Bi1.5Sb0.5Te1.7Se1.3 – in pristine form as well as covered by thin flakes of hexagonal boron nitride (hBN) is employed. Contrary to theoretical expectations, all three materials exhibit a dielectric response with a high refractive index and with a loss below the experimental detection limit. Particularly, the near‐field mapping of propagating phonon‐polaritons in hBN demonstrates that all three van der Waals crystals with different stoichiometry act as a practically lossless dielectric substrate with an ultra‐high refractive index of up to 7.5 in Bi2Te2Se. Such a unique dielectric crystal will be of great advantage for numerous nanophotonic applications in the mid‐IR.

Sulfur‐Supplemented Vapor Transport Deposition of Sb2S3 and Sb2(S,Se)3 for High‐Performance Hydrogen Evolution Photocathodes

Chalcogen vacancy has long been recognized as a detrimental deep‐level defect that can induce severe charge recombination and diminish the quasi‐Fermi‐level splitting in Sb2S3 and Sb2Se3, especially when they are prepared by physical vapor deposition in vacuum. In order to counter this limitation, a sulfur‐supplemented vapor transport deposition technique is proposed, which intentionally introduces low pressure sulfur vapor and can thus afford low‐defect‐density antimony chalcogenide films. The resultant photocathodes modified with conformal TiO2 protection layer and Pt cocatalyst demonstrate a photocurrent as high as 20 mA cm−2 along with a much improved fill factor and onset potential, achieving an applied bias photoconversion efficiency above 1%. This work highlights the importance of the vacancy defect passivation and the preferential crystalline orientation in the film in promoting the photocathode performance.

Synthesis and enhanced room-temperature thermoelectric properties of CuO-MWCNT hybrid nanostructured composites.

This work presents the synthesis of novel copper oxide-multiwalled carbon nanotube (CuO-MWCNT) hybrid nanostructured composites and a systematic study of their thermoelectric performance at near-room temperatures as a function of MWCNT wt% in the composite. The CuO-MWCNT hybrid nanostructured composites were synthesized by thermal oxidation of a thin metallic Cu layer pre-deposited on the MWCNT network. This resulted in the complete incorporation of MWCNTs in the nanostructured CuO matrix. The thermoelectric properties of the fabricated CuO-MWCNT composites were compared with the properties of CuO-MWCNT networks prepared by mechanical mixing and with the properties of previously reported thermoelectric [CuO]99.9[SWCNT]0.1 composites. CuO-MWCNT hybrid composites containing MWCNTs below 5 wt% showed an increase in the room-temperature thermoelectric power factor (PF) by ∼2 times compared with a bare CuO nanostructured reference thin film, by 5-50 times compared to mixed CuO-MWCNT networks, and by ∼10 times the PF of [CuO]99.9[SWCNT]0.1. The improvement of the PF was attributed to the changes in charge carrier concentration and mobility due to the processes occurring at the large-area CuO-MWCNT interfaces. The Seebeck coefficient and PF reached by the CuO-MWCNT hybrid nanostructured composites were 688 μV K-1 and ∼4 μW m-1 K-2, which exceeded the recently reported values for similar composites based on MWCNTs and the best near-room temperature inorganic thermoelectric materials such as bismuth and antimony chalcogenides and highlighted the potential of CuO-MWCNT hybrid nanostructured composites for applications related to low-grade waste heat harvesting and conversion to useable electricity.

Utilizing machine learning to enhance performance of thin-film solar cells based on Sb2(S x Se1-x )3: investigating the influence of material properties.

Antimony chalcogenides (Sb2(S x Se1-x )3) have drawn attention as a potential semiconducting substance for heterojunction photovoltaic (PV) devices due to the remarkable optoelectronic properties and wide range of bandgaps spanning from 1.1 to 1.7 eV. In this investigation, SCAPS-1D simulation software is employed to design an earth abundant, non-toxic, and cost-effective antimony sulfide-selenide (Sb2(S,Se)3)-based thin-film solar cell (TFSC), where tungsten disulfide (WS2) and cuprous oxide (Cu2O) are used as an electron transport layer (ETL) and hole transport layer (HTL), respectively. The PV performance parameters such as power conversion efficiency, open-circuit voltage (V oc), short-circuit current (J sc), and fill factor (FF) are assessed through adjustments in material properties including thickness, acceptor concentration, bulk defect density of the absorber, defect state of absorber/ETL and HTL/absorber interfaces, operating temperature, work function of the rear electrode, and cell resistances. This analysis aims to validate their collective impact on the overall efficiency of the designed Ni/Cu2O/Sb2(S,Se)3/WS2/FTO/Al TFSC. The optimized physical parameters for the Sb2(S,Se)3 TFSC lead to impressive PV outputs with an efficiency of 30.18%, V oc of 1.02 V, J sc of 33.65 mA cm-2, and FF of 87.59%. Furthermore, an artificial neural network (ANN) machine learning (ML) algorithm predicts the optimal PCE by considering five semiconductor parameters: absorber layer thickness, bandgap, electron affinity, electron mobility, and hole mobility. This model, which has an approximate correlation coefficient (R 2) of 0.999, is able to predict the data with precision. This numerical analysis provides valuable data for the fabrication of an environmentally friendly, economical, and incredibly non-toxic efficient heterojunction TFSC.

Thermodynamics of Formation and Liquid-Vapor Phase Transitions of Antimony Alloys with Selenium and Sulfur.

The authors conducted liquid solution studies of antimony with selenium and sulfur in order to provide information on the thermodynamic functions of the formation of these alloys. The studies are based on the vapor pressure values of the components, comprising the double partial systems of antimony with antimony chalcogenides (Sb2Se3 and Sb2S3) and antimony chalcogenides with chalcogens (Se and S). We calculated the thermodynamic functions of mixing (graphical dependencies) and evaporation (tabular data) based on the partial vapor pressure values of components, which are represented by temperature-concentration dependencies. Based on the partial pressure values of melt components, we calculated the boundaries of liquid and vapor coexistence fields at atmospheric pressure (101.3 kPa) and in a vacuum (0.9 kPa). We established the absence of the stratification region on the Sb2S3-S diagram due to the fact that, on state diagrams, the stratification region is indicated at temperatures above 530 °C, while the boiling point of liquid sulfur at an atmospheric pressure corresponds to 429 °C. Based on the position of the field boundaries (L + V) on the state diagrams, the separation of antimony alloys with selenium and sulfur via distillation into elements at atmospheric pressure is difficult due to the high boiling points of antimony-based alloys in a vacuum: Sb2Se3-Se melts require some number of condensate re-evaporation cycles.

High-Rate Performance of Antimony Chalcogenides (Sb2X3) Studied By Operando X-Ray Diffraction (XRD)

Na-ion batteries (NIBs) represent an environmentally-friendly and sustainable alternative to Li-ion batteries (LIBs), owing to the higher abundance of Na compared to Li. [1] However, many challenges associated with the successful implementation of NIBs are yet to be addressed, which includes the optimization of the present set of materials. Among others, the development of high-performing anode materials as a replacement for conventionally used hard carbon is essential to deliver NIBs with high energy density. A class of materials promising for implementation in NIBs is based on the combined conversion/alloying reaction pathway as a main motive of their operating mechanism. [2] However, such conversion/alloying materials (CAMs) typically undergo a set of complex structural and chemical transformations during electrochemical cycling (formation of new phases, amorphization, etc). [3] Investigation of the (de)sodiation mechanism using advanced characterization techniques, such as operando X-ray diffraction (XRD), is therefore the key to revealing the true potential of these battery mechanisms.Among many CAMs, Sb-based chalcogenides (Sb2X3, where X = O, S, Se, Te) have demonstrated superior electrochemical performance in NIBs. In the present work, the research efforts have been focused on elucidating the (de)sodiation mechanism of Sb2Se3/Sb (Sb-rich Sb2Se3) materials using operando XRD. The study reveals the true complexity of the (de)sodiation mechanism for Sb2Se3/Sb (Figure 1), where the active material passes through a combination of multiple phases (Na2Se, Na2Se4, Sb, NaSb, hexagonal Na3Sb, cubic Na3Sb) during sodiation, where some of these phases are amorphous.One of the discovered benefits of such chalcogenide materials is the ability to operate at high cycling rates. Therefore, another objective of this study is to understand if and how the (de)sodiation mechanism change as a function of the C-rate. The preliminary operando XRD analysis suggests that kinetics plays a crucial role in the formation of certain phases during cycling leading to a rate-dependent cycling mechanism. Thus, a systematic study utilizing specific currents of 100 mA g-1, 1000 mA g-1, and 5000 mA g-1 have been applied to the Sb2Se3/Sb system to deepen the understanding of the (de)sodiation mechanism.This presentation will underpin the fundamentals of the cycling mechanism of Sb2Se3/Sb using operando XRD as a function of cycling rates. A better knowledge of the various mechanisms by which sodium can move in and out of this material is crucial for our understanding and potentially mitigate the limited cycling stability that limits their practical usefulness.References. Hasa, I., et al., Challenges of today for Na-based batteries of the future: From materials to cell metrics. Journal of Power Sources, 2021. 482: p. 228872. Skurtveit, A., et al., Benefits and Development Challenges for Conversion-Alloying Anode Materials in Na-Ion Batteries. Frontiers in Energy Research, 2022. 10. Brennhagen, A., et al., Understanding the (De)Sodiation Mechanisms in Na‐Based Batteries through Operando X‐Ray Methods. Batteries & Supercaps, 2021. 4(7): p. 1039-1063. Figure 1

Exploring the potential of standalone and tandem solar cells with Sb2S3 and Sb2Se3 absorbers: a simulation study

Thin-film antimony chalcogenide binary compounds are potential candidates for efficient and low-cost photovoltaic absorbers. This study investigates the performance of Sb2S3 and Sb2Se3 as photovoltaic absorbers, aiming to optimize their efficiency. The standalone Sb2S3 and Sb2Se3 sub-cells are analyzed using SCAPS-1D simulations, and then a tandem structure with Sb2S3 as the top-cell absorber and Sb2Se3 as the bottom-cell absorber is designed, using the filtered spectrum and the current matching technique. The optimal configuration for maximum efficiency is achieved by adjusting the thickness of the absorber layer. The results show that antimony chalcogenide binary compounds have great potential as photovoltaic absorbers, enabling the development of efficient and low-cost solar cells. A remarkable conversion efficiency of 22.2% is achieved for the optimized tandem cell structure, with absorber thicknesses of 420 nm and 1020 nm for the top and bottom sub-cells respectively. This study presents a promising approach towards high-performance tandem solar cells.

Bi2O2S topological transformation and in-situ regrowth of [hk1]-oriented SbBiS3-xSex 2D skeleton structure for construction of efficient quasi-two-dimensional Sb2S3-xSex-based heterojunction photoanodes

Antimony chalcogenides (Sb2S3-xSex), as one of the promising light-absorbing materials in optoelectronic energy storage devices, has attracted widespread attention in recent years. Of particular note, its crystal structure consists of the one-dimensional [Sb4S(Se)6]n ribbons with efficient carrier transport efficiency along the [hk1] direction. In this paper, with the aid of the topological transformation of the layered material Bi2O2S, the SbBiS3-xSex bimetallic alloy with 2D skeleton structure was induced to grow in situ, and the conversion of Sb2S3-xSex preferred orientation from [hk0] to [hk1] was realized. The corresponding results showed that 2D skeleton structure was conducive to the construction of photo traps and the increase of electrochemical specific surface area. In addition, Bi2O2S acted as an electron transport layer (ETL) to further promote the migration of photogenerated carriers. At 1.23 V vs. RHE, the photocurrent density of quasi-two-dimensional Bi2O2S/SbBiS3-xSex nanosheet photoanode was as high as 6.41 mA cm−2, which was 7.5 times that of pure Sb2S3-xSex, and the peak value of IPCE could reach 40.93%. This work undoubtedly opens up a new avenue for the designing high-efficiency antimony chalcogenides photoelectrodes.

Optical loss analysis of Sb2S3 and Sb2Se3 thin film solar cells: A Quantitative Assessment

Optical loss either by light reflection, or light absorption in different layers of a solar cell, can significantly impact short-circuit current density. In this paper, an optical model has been developed to analyze the optical loss in thin film solar cells made of CdS/Sb2S3 or CdS/Sb2Se3 antimony chalcogenide. This model is based on optical loss from absorption in thin layers and reflection at the interfaces of glass/TCO/CdS/(Sb2S3 or Sb2Se3) only by considering the optical properties of layers (refractive index and extinction coefficient). The transmission and reflection rate of Sb2S3 or Sb2Se3 show almost a similar trend. The absorptivity and relative loss in short-circuit current density (Jsc) versus the thickness of Sb2S3 and Sb2Se3 layers was calculated for two different structures: glass/TCO/CdS/Sb2S3 and glass/TCO/CdS/Sb2Se3. The Sb2Se3 solar cell shows a slightly better conversion performance compared to Sb2S3 solar cell due to lower reflection loss. The light reflection was calculated at four interfaces. The transmission rate of light through TCO, ITO, and CdS layers was calculated to obtain an optimal thickness for these layers. TCO showed a higher transmission rate and thus is preferred in antimony solar cell structures. The variations of (Jsc) and loss for Jsc with different thicknesses of ITO (>20%) or TCO (<20%) contact layers, favoring TCO for its lower optical losses and higher Jsc (24 mA cm−2).

Critical Review on Crystal Orientation Engineering of Antimony Chalcogenide Thin Film for Solar Cell Applications.

The emerging antimony chalcogenide (Sb2 (Sx Se1-x )3 , 0 ≤ x ≤ 1) semiconductors are featured as quasi-1D structures comprising (Sb4 S(e)6 )n ribbons, this structural characteristic generates facet-dependent properties such as directional charge transfer and trap states. In terms of carrier transport, proper control over the crystal nucleation and growth conditions can promote preferentially oriented growth of favorable crystal planes, thus enabling efficient electron transport along (Sb4 S(e)6 )n ribbons. Furthermore, an in-depth understanding of the origin and impact of the crystal orientation of Sb2 (Sx Se1-x )3 films on the performance of corresponding photovoltaic devices is expected to lead to a breakthrough in power conversion efficiency. In fact, there are many studies on the orientation control of Sb2 (Sx Se1-x )3 colloidal nanomaterials. However, the synthesis of Sb2 (Sx Se1-x )3 thin films with controlled facets has recently been a focus in optoelectronic device applications. This work summarizes methodologies that are applied in the fabrication of preferentially oriented Sb2 (Sx Se1-x )3 films, including treatment strategies developed for crystal orientation engineering in each process. The mechanisms in the orientation control are thoroughly analyzed. An outlook on perspectives for the future development of Sb2 (Sx Se1-x )3 solar cells based on recent research and issues on orientation control is finally provided.

A CTL-free homo-heterojunction antimony chalcogenide solar cell: Theoretical study

Exploring antimony chalcogenide as photovoltaic (PV) absorber material for solar cell is an appealing strategy. However, the conversion efficiency (η) of antimony chalcogenide solar cells including antimony selenide (Sb2Se3), antimony sulfide (Sb2S3) and antimony sulfide–selenide (Sb2(S,Se)3) lag far behind their Shockley−Queisser limit efficiency. Generally, the device PV performance of thin film heterojunction solar cells is mainly affected by the material properties of each functional layer, as well as the device architecture and heterointerface characteristics. Herein, a novel homo-heterojunction antimony chalcogenide solar cell without any carrier transport layer (CTL) consisting of FTO/(n)Sb2Se3/(p)Sb2Se3/(p)Sb2S3/Metal has been proposed. The influence of thickness, doping concentration and bulk defect density of the functional layer materials, the interface defect density at (p)Sb2Se3/(p)Sb2S3 heterointerfaces, and back contact metal work function on device PV performance have been theoretically analyzed utilized wxAMPS software. After optimization, the proposed solar cell has an open-circuit voltage (Voc) of 0.885 V, a short-circuit current density (Jsc) of 36.14 mAcm−2, a filling factor (FF) of 84.30 %, and a η of 26.97 %. These results indicate that the novel homo-heterojunction antimony chalcogenide solar cell without any CTL have the potential to become a high-efficiency PV device.