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Deep‐level defects in semiconductor materials usually induce carrier trapping and non‐radiative recombination. However, defects caused by unintentional contaminants in antimony selenide (Sb2Se3) solar cells have rarely been reported. Herein, the correlation between defect properties and unintentional impurities in the Sb2Se3 absorber is investigated, which is prepared by injection vapor deposition with Sb2Se3 source purities ranging from 99.9% to 99.9999%. The analysis of deep‐level transient spectra reveals that an increase in impurity concentration does not result in new defect types. Nevertheless, the higher impurity level causes an increase in both the defect density and the capture cross section of the original defect. To address this challenge, defect engineering is developed to regulate the growth of the Sb2Se3 absorber. This strategy completely suppresses deepest defect states E3, a mixture of intrinsic defect (SbSe) and impurity Si related defect. As a result, the carrier lifetime increases significantly from 0.37 to 3.4 ps. This enables to fabricate Sb2Se3 solar cells with a power conversion efficiency of 10.41%. This work uncovers the characteristics of unintentional contaminant‐related defects, and provides a strategy for fabricating highly efficient Sb2Se3 solar cells with low‐purity source materials. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb2Se3) photovoltaic thin-film materials have been recognized as suitable thin-film photovoltaic candidates for sustainable development due to the low toxicity of their constituent elements and abundant reserves. In this study, we employed the close space sublimation (CSS) method to fabricate solar cells with the FTO/SnO2/Sb2Se3/P3HT/C device architecture. By optimizing the deposition time, we achieved (hk1) orientation-preferred Sb2Se3 films, the optimized device exhibited a peak efficiency of 5.06%. This work investigated the growth mechanism of antimony selenide using a complete characterization technique, while the experimental parameters were simulated and matched using Widget Provided Analysis of Microelectronic and Photonic Structures (wxAMPS) showing excellent potential in the deposition of optoelectronic thin films by close space sublimation. [ABSTRACT FROM AUTHOR]

In this paper, antimony sulfide (Sb2S3) material is utilized as an electron reflector layer (ERL) in antimony selenide (Sb2Se3) solar cells. The primary objective of this simulation study is to mitigate recombination at the back contact and improve cell performance. It is demonstrated that incorporating Sb2S3 ERL into a traditional Sb2Se3 cell yields enhancements in both the short‐circuit current density (Jsc) and carrier collection rate. This enhancement is assigned to the reduced interface recombination rate at the back electrical contact. The strong electric field at the p+‐Sb2S3/p‐Sb2Se3 electrical contact creates a barrier with a height of 0.34 eV in the conduction band that hinders the electron carriers' access to the back contact. This barrier effectively improves cell efficiency. The use of this method has demonstrated a significant improvement in the external quantum efficiency (EQE) at longer wavelengths, specifically ranging from ≈800 to 1100 nm. Using this method, the Sb2Se3 active layer thickness is reduced to 1 µm, which reduces the fabrication cost. After optimizing the device, the cell efficiency enhances from 9.2% to 13.1%, resulting in a significant improvement compared to traditional Sb2Se3 solar cells without an ERL, thanks to the incorporation of a suitable Sb2S3 ERL. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb2Se3) photovoltaic thin-film materials have been recognized as suitable thin-film photovoltaic candidates for sustainable development due to the low toxicity of their constituent elements and abundant reserves. In this study, we employed the close space sublimation (CSS) method to fabricate solar cells with the FTO/SnO2/Sb2Se3/P3HT/C device architecture. By optimizing the deposition time, we achieved (hk1) orientation-preferred Sb2Se3 films, the optimized device exhibited a peak efficiency of 5.06%. This work investigated the growth mechanism of antimony selenide using a complete characterization technique, while the experimental parameters were simulated and matched using Widget Provided Analysis of Microelectronic and Photonic Structures (wxAMPS) showing excellent potential in the deposition of optoelectronic thin films by close space sublimation.

Antimony selenide (Sb2Se3) is an ideal photovoltaic candidate profiting from its advantageous material characteristics and superior optoelectronic properties, and has gained considerable development in recent years. However, the further device efficiency breakthrough is largely plagued by severe open‐circuit voltage (VOC) deficit under the existence of multiple defect states and detrimental recombination loss. In this work, an effective absorber layer growth engineering involved with vapor transport deposition and post‐selenization is developed to grow Sb2Se3 thin films. High‐quality Sb2Se3 with large compact crystal grains, benign [hk1] growth orientation, stoichiometric chemical composition, and suitable direct bandgap are successfully fulfilled under an optimized post‐selenization scenario. Planar Sb2Se3 thin‐film solar cells with substrate configuration of Mo/Sb2Se3/CdS/ITO/Ag are constructed. By contrast, such engineering effort can remarkably mitigate the device VOC deficit, owing to the healed detrimental defects, the suppressed interface and space‐charge region recombination, the prolonged carrier lifetime, and the enhanced charge transport. Accordingly, a minimum VOC deficit of 0.647 V contributes to a record VOC of 0.513 V, a champion device with highly interesting efficiency of 7.40% is also comparable to those state‐of‐the‐art Sb2Se3 solar cells, paving a bright avenue to broaden its scope of photovoltaic applications. [ABSTRACT FROM AUTHOR]

Abstract Antimony selenide (Sb2Se3) is an ideal photovoltaic candidate profiting from its advantageous material characteristics and superior optoelectronic properties, and has gained considerable development in recent years. However, the further device efficiency breakthrough is largely plagued by severe open‐circuit voltage (VOC) deficit under the existence of multiple defect states and detrimental recombination loss. In this work, an effective absorber layer growth engineering involved with vapor transport deposition and post‐selenization is developed to grow Sb2Se3 thin films. High‐quality Sb2Se3 with large compact crystal grains, benign [hk1] growth orientation, stoichiometric chemical composition, and suitable direct bandgap are successfully fulfilled under an optimized post‐selenization scenario. Planar Sb2Se3 thin‐film solar cells with substrate configuration of Mo/Sb2Se3/CdS/ITO/Ag are constructed. By contrast, such engineering effort can remarkably mitigate the device VOC deficit, owing to the healed detrimental defects, the suppressed interface and space‐charge region recombination, the prolonged carrier lifetime, and the enhanced charge transport. Accordingly, a minimum VOC deficit of 0.647 V contributes to a record VOC of 0.513 V, a champion device with highly interesting efficiency of 7.40% is also comparable to those state‐of‐the‐art Sb2Se3 solar cells, paving a bright avenue to broaden its scope of photovoltaic applications.

The performance of thermally deposited Sb2Se3 solar cells are severely limited by various bulk and interfacial recombination, instigating a large open‐circuit voltage (VOC) deficit. Ternary Sb2(S,Se)3 is considered as a remedy, however, it is also subjected to a dilemma that improvement in VOC will be escorted by JSC loss due to the shrinkage of light harvest. Thus, a gradient of S/Se across the film is a prerequisite to avoid this detrimental compromise. Herein, the incorporation of S in the Sb2Se3 absorber layer evaporated from a CdS buffer layer during vapor transport deposition (VTD) process, and its further self‐activated diffusion at the interface upon ambient storage is explored. For the gradient indium tin oxide (ITO)/CdS/Sb2(S,Se)3/Sb2Se3/Au solar cell, the large bandgap Sb2(S,Se)3 at the heterojunction side contributes to high VOC, while the narrow bandgap Sb2Se3 at the top side confirms high JSC. Sulfur diffusion at the CdS/Sb2Se3 interface also improves the junction quality with an enlarged Vbi, reduced interfacial defects and recombination loss, thus improving VOC from 393 to 430 mV. Such VOC represents the highest value for that of thermally deposited Sb2Se3 solar cells. The champion device also delivers an interesting efficiency of 7.49%. This research provides substantial guidance in exploring efficient approaches to improve the performance of Sb2Se3 solar cells. [ABSTRACT FROM AUTHOR]

Sb2Se3 possesses a quasi‐1D (Q1D) structure, which creates an anisotropic charge transporting behavior in which the carrier transport is very efficient along the Q1D direction, which is beneficial for solar cells as long as the absorber is properly aligned along the preferred orientation. However, Sb2Se3 is prone to form donor‐like defects, such as VSe, that are detrimental to the performance. Therefore, both growth of Sb2Se3 along the preferred orientations and the suppression of the formation of VSe are crucial in achieving Sb2Se3 solar cells with a high efficiency. Herein, the importance of fine control of the extra supply of Se during the deposition of Sb2Se3 in controlling crystallographic orientations and the population of VSe in the Sb2Se3 films is described. This control determines the performance of the resulting solar cells in a superstrate configuration with a CdS buffer. Incorporation of Se during the growth resulted in a larger open‐circuit voltage due to the passivation of VSe. However, an excess supply of Se disrupts the favorable orientation by selenizing the top region of the CdS, and therefore degraded the short‐circuit current. Through the optimization of the extra supply of Se vapor, the power conversion efficiency is improved from 3.7% to 5.2%. [ABSTRACT FROM AUTHOR]

This work reports a numerical investigation on the performance of Sb2Se3‐based thin‐film heterojunction solar cell using the solar cell capacitance simulator in 1D (SCAPS‐1D) program. Herein, inorganic tin sulfide (SnS) is introduced as a new hole transport material into the Sb2Se3 solar cell. The effects of several parameters such as thickness, doping, electron affinity, defect density, temperature, and resistances on the cell performances are analyzed. The proposed novel solar configuration that consists of Al/F:SnO2 (FTO)/CdS/Sb2Se3/SnS/Mo reveals the enhanced photovoltaic performances by means of reducing carrier recombination loss at back surface. At an optimized Sb2Se3 thickness of 1.0 μm, the efficiency is boosted from 24.01% to 29.89% by incorporating an ultrathin 0.05 μm SnS hole transport layer (HTL) into the Sb2Se3 solar cell. The performances of the proposed device are also evaluated by varying defects at CdS/Sb2Se3 and Sb2Se3/SnS interfaces. Moreover, it is found that electron affinity larger than 3.5 eV of HTL as well as back contact metal work function ≥4.9 eV should be considered to attain better performance. The simulated results lead to suggest that introducing the SnS material as a potential HTL candidate would be useful to develop low‐cost and highly efficient thin‐film solar cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low cost and stable solution-processed inorganic NiOx hole transport layer for Sb 2 Se 3 solar cells. • Close space sublimation deposition of the Sb 2 Se 3 absorber material. • Sb 2 Se 3 with NiOx hole transport layer achieve a power conversion efficiency ~7.3%. • The stability of the Sb 2 Se 3 solar cells with NiOx hole transport layer can be improved. Sb 2 Se 3 is a promising absorber material for thin-film solar cells owing to its earth-abundant and non-toxic constituents, superior optoelectronic properties, and unique one-dimensional crystal structure. To further increase the power conversion efficiency of the Sb 2 Se 3 , we fabricated an n-i-p structure by integrating a solution-processed NiO x hole-transport layer (HTL) into Sb 2 Se 3 solar cells to enhance the carrier collection. In this study, we systematically screen the thickness of NiO x HTL and demonstrate an improved average power conversion efficiency from 6.12% to 7.15% with a 50 nm NiO x HTL. The mechanism associated with the improved device performance was characterized through the microstructure of the material, device physics, and interface electronic behaviors. It is also shown that the low-cost and scalable solution-processed NiO x HTL can improve device stability under an accelerated stress test. Thus, this work paves a way to further improve the performance of antimony chalcogenides-based solar cells via tailoring the inorganic HTL. [ABSTRACT FROM AUTHOR]

Abstract Environmentally benign and potentially cost‐effective Sb2Se3 solar cells have drawn much attention by continuously achieving new efficiency records. This article reports a compatible strategy to enhance the efficiency of planar n–i–p Sb2Se3 solar cells through Sb2Se3 surface modification and an architecture with oriented 1D van der Waals material, trigonal selenium (t‐Se). A seed layer assisted successive close spaced sublimation (CSS) is developed to fabricate highly crystalline Sb2Se3 absorbers. It is found that the Sb2Se3 absorber exhibits a Se‐deficient surface and negative surface band bending. Reactive Se is innovatively introduced to compensate the surface Se deficiency and form an (101) oriented 1D t‐Se interlayer. The p‐type t‐Se layer promotes a favored band alignment and band bending at the Sb2Se3/t‐Se interface, and functionally works as a surface passivation and hole transport material, which significantly suppresses interface recombination and enhances carrier extraction efficiency. An efficiency of 7.45% is obtained in a planar Sb2Se3 solar cell in superstrate n–i–p configuration, which is the highest efficiency for planar Sb2Se3 solar cells prepared by CSS. The all‐inorganic Sb2Se3 solar cell with t‐Se shows superb stability, retaining ≈98% of the initial efficiency after 40 days storage in open air without encapsulation.

Environmentally benign and potentially cost‐effective Sb2Se3 solar cells have drawn much attention by continuously achieving new efficiency records. This article reports a compatible strategy to enhance the efficiency of planar n–i–p Sb2Se3 solar cells through Sb2Se3 surface modification and an architecture with oriented 1D van der Waals material, trigonal selenium (t‐Se). A seed layer assisted successive close spaced sublimation (CSS) is developed to fabricate highly crystalline Sb2Se3 absorbers. It is found that the Sb2Se3 absorber exhibits a Se‐deficient surface and negative surface band bending. Reactive Se is innovatively introduced to compensate the surface Se deficiency and form an (101) oriented 1D t‐Se interlayer. The p‐type t‐Se layer promotes a favored band alignment and band bending at the Sb2Se3/t‐Se interface, and functionally works as a surface passivation and hole transport material, which significantly suppresses interface recombination and enhances carrier extraction efficiency. An efficiency of 7.45% is obtained in a planar Sb2Se3 solar cell in superstrate n–i–p configuration, which is the highest efficiency for planar Sb2Se3 solar cells prepared by CSS. The all‐inorganic Sb2Se3 solar cell with t‐Se shows superb stability, retaining ≈98% of the initial efficiency after 40 days storage in open air without encapsulation. [ABSTRACT FROM AUTHOR]

Antimony triselenide (Sb 2 Se 3 ) has possessed excellent optoelectronic properties and has gained interest as a light-harvesting material for photovoltaic technology over the past several years. However, the severe interfacial and bulk recombination obviously contribute to significant carrier transport loss thus leading to the deterioration of power conversion efficiency (PCE). In this work, buried interface and heterojunction engineering are synergistically employed to regulate the film growth kinetic and optimize the band alignment. Through this approach, the orientation of the precursor films is successfully controlled, promoting the preferred orientational growth of the (hk1) of the Sb 2 Se 3 films. Besides, interfacial trap-assisted nonradiative recombination loss and heterojunction band alignment are successfully minimized and optimized. As a result, the champion device presents a PCE of 9.24% with short-circuit density (J SC ) and fill factor (FF) of 29.47 mA cm -2 and 63.65%, respectively, representing the highest efficiency in sputtered-derived Sb 2 Se 3 solar cells. This work provides an insightful prescription for fabricating high-quality Sb 2 Se 3 thin film and enhancing the performance of Sb 2 Se 3 solar cells., (© 2023 Wiley-VCH GmbH.)

Highlights • Sb 2 Se 3 solar cells with alternative back contacts have been examined. • Formation of interface defects and metal diffusion deteriorated device performance. • Optimal NiO x thickness was 7 nm and 6.5% PCE was achieved. Abstract In this study, alternative back contacts for Sb 2 Se 3 solar cells are explored with an aim to replace commonly used expensive gold electrode. Various low-cost contacts were tested including large work function metals such as Ni and Co. The performance of solar cells with bare metallic electrodes was lower up to 45% when compared to the reference device with Au contact, and was attributed mainly to the large back interface barrier for hole extraction. Additionally, shunt resistance of solar cells decreased significantly when Ni contact were employed as a result of metal diffusion and formation of interface defects. Thermally evaporated thin NiO x was used as a blocking layer for diffusion and mitigating hole extraction barrier. Solar cells with 7 nm of NiO x layer and Ni contact achieved 97% of reference solar cell performance. Over the period of 25 days, solar cells with 7 nm NiO x /Ni as a back contact retained 93% of initial performance, demonstrating that Au contacts can be successfully replaced by low-cost materials and retain high performance. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb 2 Se 3) has rapidly emerged in the field of photovoltaics with one-dimensional crystal structure. However, the power conversion efficiency (PCE) of Sb 2 Se 3 solar cells is influenced by the orientation of the Sb 2 Se 3 photoactive layers. In this study, we investigate the influence of substrate properties on the preferred orientation and microstructure of Sb 2 Se 3 films systematically. With the rise of substrate surface temperature and the decline of substrate surface bonding energy, the preferred orientation of the Sb 2 Se 3 films altered from (hk0) to (hk1) and finally to (002). After summarizing the performance of different preferentially oriented Sb 2 Se 3 solar cells, the results showed that the (hk0)-preferentially oriented devices exhibited a poor performance of less than 1.1 %. As the preferred orientation of Sb 2 Se 3 absorbers changed from (hk0) to (hk1), the carrier transport changed from inter-ribbon charge hopping to transportation along the (Sb 4 Se 6) n ribbons. This enhanced the carrier transport efficiency, thereby leading to the enhancement of the PCE to 2–3 %. Furthermore, when the (002) texture coefficient (TC) of the Sb 2 Se 3 films was between 1.8 and 3.6, the PCE of the devices was further enhanced to above 3.5 %. A maximum PCE of 4.79 % can be obtained when the (002) TC was 3.24. This study reveals the relationship between the Sb 2 Se 3 film preferred orientation and device performance, and demonstrates an effective way to precisely control the Sb 2 Se 3 film microstructure to obtain a high PCE. [Display omitted] • Sb 2 Se 3 is applied to photovoltaics with one-dimensional crystal structures. • Power-conversion efficiency of Sb 2 Se 3 is affected by the orientation of its films. • This changes with an increase in substrate surface temperature. • A decrease in substrate surface bonding energy also changes the orientation. • We achieved precise control of Sb 2 Se 3 film microstructures to obtain a high PCE. [ABSTRACT FROM AUTHOR]

As one of the most-successful n-type semiconductor material, cadmium sulfide (CdS) films have proven advantageous in thin film solar cells by a traditional chemical bath deposition (CBD) process. However, the CBD process generates large quantities of waste containing Cd2+, S2− and ammonia. Metal-organic solution coating method (MOSC) shows the outstanding advantages in fabrication metal sulfide thin films, such as the less waste during film fabrication, low preparation cost and high-productivity of raw material. Herein, pinhole-free, crack-free and uniform CdS thin films were made by MOSC and CBD, then served as the buffer layers of superstrate Sb 2 Se 3 solar cells, respectively. The Sb 2 Se 3 solar cells exhibit impressive conversion efficiency of 5.93%, demonstrating the great potential of MOSC to replace the traditional CBD process. • We demonstrated a general and highly productive solution approach of metal-organic solution coating method to make CdS thin film. • The properties of as-prepared films were analyzed through atomic force microscopy (AFM), UV–Vis absorption and so on. • An efficiency of 5.93% was obtained based on spin-coated CdS buffer layer, which is comparable to the traditional chemical bath deposition CdS. [ABSTRACT FROM AUTHOR]

• SnO 2 nanoparticle films were employed as the electron transport layers for devices. • SnO 2 surface was modified by CdCl 2 solution. • The PCE of optimized device has rapidly surged from 2.02% to 4.03%. • The cell can remain its initial value about 4.0% after a 150 day storage in ambient air (~25 °C, 40% RH). Antimony selenide (Sb 2 Se 3) is a promising light-absorbing material for the thin-film solar cells (TFSCs). However, the low efficiency output of the Sb 2 Se 3 -based TFSC is still one of the largest obstacles to restrain its development. In this work, tin oxide (SnO 2) nanoparticle film is used as the electron transport layer (ETL) for the Sb 2 Se 3 -based TFSC. To further enhance the device performance, spin coated CdCl 2 films are employed to modify the SnO 2 ETL. As a result, preferable orientation with an increased intensity of (2 2 1) peak and a reduced intensity of (1 2 0) peak in the XRD patterns are observed for the Sb 2 Se 3 film, which enhances the carrier transport within the Sb 2 Se 3 absorber. Meanwhile, the CdCl 2 suppresses the carrier recombination at the interface between the Sb 2 Se 3 and SnO 2. Therefore, the optimized device shows an improved power conversion efficiency from 2.02% to 4.03%, and also exhibits a strong stability in ambient air. [ABSTRACT FROM AUTHOR]

• Solution-processed SnO 2 electron transport layer was applied to Sb 2 Se 3 solar cells. • The conductivity of the SnO 2 layer was significantly improved by CdCl 2 treatment. • Longitudinal growth of Sb 2 Se 3 grains can be induced by the CdCl 2 treated SnO 2 layer. • The efficiencies of the Sb 2 Se 3 solar cells were enhanced from 0.12% to 4.76%. The electron transport layer (ETL) of Sb 2 Se 3 thin film solar cells is not only responsible for electron extraction and transport but also manipulates the orientation of the Sb 2 Se 3 photoactive layer's growth, which is crucial for performance optimization. In this study, the dual functionality of solution-processed SnO 2 film treated with CdCl 2 was achieved as the ETL in Sb 2 Se 3 solar cells. The CdCl 2 treatment simultaneously improves the efficacy of the SnO 2 ETL and induces the longitudinal growth of Sb 2 Se 3 grains. These two aspects effectively enhance electron transport and/or extraction, thereby reducing the charge recombination, which contributes to the improvement of all device parameters. The results demonstrate that CdCl 2 treatment optimizes the interface properties of the SnO 2 ETL, providing a facile and effective method for enhancing the performance of the Sb 2 Se 3 solar cell. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the effect of Zn 1-y Mg y O/ZnO 1-x S x double buffer layers on the antimony selenide (Sb 2 Se 3) solar cells performance. Our results show that the magnesium and sulfur concentrations in proposed double buffer layers have a significant effect on the band alignment optimization at the junctions. The flexibility with Zn 1-y Mg y O/ZnO 1-x S x double buffer layers ranging from 0 to 25% magnesium and 10%–70% sulfur allows an optimal conduction band offset (CBO) for Sb 2 Se 3 solar cells. An improved open-circuit voltage (V oc) was observed in the Sb 2 Se 3 solar cell with Zn 0.93 Mg 0.07 O/ZnO 0.4 S 0.6 proposed double buffer layers due to appropriate CBO values at the junction interfaces. The short-circuit current density (J sc) values increased as the sulfur concentration in the ZnO 1-x S x buffer layer increased from 0 to 0.7 (x value), which could be related to the increase in the optical band gap of the ZnO 1-x S x layer. The results demonstrated that under small positive offset conditions (spike-like), the carrier recombination rate at the interface is reduced, and consequently, the Sb 2 Se 3 solar cell performance is improved. A Sb 2 Se 3 solar cell with the optimum CBO amount (+0.3 eV) represented a conversion efficiency of 15.46%, which exhibited a 68% enhancement in comparison to the traditional CdS/Sb 2 Se 3 solar cell. • The purpose is optimizing the CBO at junction interface in Sb 2 Se 3 solar cells. • Traditional ZnO/CdS buffer layer replaced by (Zn,Mg)O/Zn(O,S) in Sb 2 Se 3 solar cell. • ZnO:Al/Zn 0.93 Mg 0.07 O/ZnO 0.4 S 0.6 /TiO 2 /Sb 2 Se 3 /MoSe 2 /Mo is the optimized cell. • Efficiency of Sb 2 Se 3 solar cells improved by relative gain of 6%. [ABSTRACT FROM AUTHOR]

Sb 2 Se 3 is an emerging and promising light-absorbing material with superior photovoltaic properties. However, the specific one-dimensional structure of Sb 2 Se 3 limits the doping density, preventing a high built-in potential. Moreover, in the superstrate devices the back contact is often non-ohmic. In this work, we have successfully applied tungsten oxide (WO 3- x ) as a hole-transport layer in superstrate n-i-p Sb 2 Se 3 solar cells. It is found that an interfacial dipole is formed at Sb 2 Se 3 /WO 3- x interface via Sb-W bonds, which reduces the barrier for hole extraction. Meantime, gap states are present at a suitable energy level to serve as intermediate states for hole-transport from the Sb 2 Se 3 absorber to the metal anode. In addition, the introduction of WO 3- x can suppress carrier recombination at the back interface, enhance the built-in potential, and improve the spectral response in the long-wavelength region. Consequently, the superstrate devices with the incorporated WO 3- x layer achieve a champion efficiency of 7.10% due to the enhancement of all device parameters. Furthermore, the all-inorganic devices with WO 3- x hole-transport layer exhibit excellent air stability and thermal stability.

Environmentally benign and potentially cost-effective Sb 2 Se 3 solar cells have drawn much attention by continuously achieving new efficiency records. This article reports a compatible strategy to enhance the efficiency of planar n-i-p Sb 2 Se 3 solar cells through Sb 2 Se 3 surface modification and an architecture with oriented 1D van der Waals material, trigonal selenium (t-Se). A seed layer assisted successive close spaced sublimation (CSS) is developed to fabricate highly crystalline Sb 2 Se 3 absorbers. It is found that the Sb 2 Se 3 absorber exhibits a Se-deficient surface and negative surface band bending. Reactive Se is innovatively introduced to compensate the surface Se deficiency and form an (101) oriented 1D t-Se interlayer. The p-type t-Se layer promotes a favored band alignment and band bending at the Sb 2 Se 3 /t-Se interface, and functionally works as a surface passivation and hole transport material, which significantly suppresses interface recombination and enhances carrier extraction efficiency. An efficiency of 7.45% is obtained in a planar Sb 2 Se 3 solar cell in superstrate n-i-p configuration, which is the highest efficiency for planar Sb 2 Se 3 solar cells prepared by CSS. The all-inorganic Sb 2 Se 3 solar cell with t-Se shows superb stability, retaining ≈98% of the initial efficiency after 40 days storage in open air without encapsulation., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)