It is possible to use solar energy to fulfil the increasing demand for energy worldwide needs. As solar energy usage rises, the latest PV (photovoltaic) technological advances having low production costs and significant PCE are also necessary [1]. Because of the advantages of lower material utilization, and adaptable versatility, thin-film photovoltaic (TFPV) innovations, and higher potency output have gained interest significant investigated attention [[2], [3], [4]]. Remarkable advancements have been achieved for multiple TFSC varieties in the indicative CdTe [5], CuIGS [6,7], and perovskites [[8], [9], [10], [11], [12]] solar cells. Their long-term use is constrained owing to the limited availability of cadmium (Cd) and indium's (In) noxiousness. Diverse environmentally friendly and non-hazardous photo absorber materials, including CZTS(e) SnSCu2O, CuSbSe2, and Sb2Se3, have been evaluated for PV applications [10,11]. Antimony selenide (Sb2Se3) is one of the chalcogenides that has shown promise as the next generation of light-harvesting materials as its absorption coefficients level is high (>105 cm−1), presence of 6–8 minimal-toxic constituents, and suitably high band-gap of energy 1.1–1.2 eV [12,13]. This material is an inexpensive and harmless substance with utilizing band gap of 1.2 eV [14].

Due to the material's excellent light response and significant thermoelectric capability, Sb2Se3 has been attracting considerable research attention over the last few years [15], which support usage in cooling devices using optics and thermoelectricity. Sb2Se3 has a variety of implementations in photodetectors, solar cells, batteries, and memory storage units in addition to these [16]. All these applications heavily rely on the electronic, optical, nano-structural, and other properties of Sb2Se3. To achieve a higher level of material quality, material synthesis and deposition are equally important. Sb2Se3 solar cells have undergone extensive research over the past ten years, yielding considerable advancements with PCEs of 3.21%, 7.6%, and 9.2% [2]. In contrast, numerical simulation methods on Sb2Se3 solar cells with various heterostructures of CD's/Sb2Se3 [17], ZnO/CdS/Sb2Se3 [18], HTL/Sb2Se3/ETL [19], In2S3/Sb2Se3/Cu2O [20], Zn(Sn,O)/Sb2Se3/CZTSe [21], CdS(ETL)/Sb2Se3/SnS(HTL) [22], PEDOT:PSS(HTL)/Sb2Se3/ZnS(ETL) [23], show that the conversion efficiency ranges between 11.52 and 30%.

This improved PCE was attributed to a number of factors, including improved buffer layer enhancement (CdTe, ZnO, and TiO2), enhanced absorber development techniques (such as hydrothermal processes, near-space sublimation, and vapor transfer accumulation), and innovative architectural device configurations [24]. In contrast, despite the Sb2Se3 cells' low photovoltage display, the device's performance improved. According to several experiments [25], extra holes were extracted from the rear contact following the inhibition of the downward bending of the band. It was mentioned that antimony chalcogenide solar cells (such as Sb2Se3) need a more advantageous hole transport layer in comparison to different solar cells. Additionally, Chen et al. (2017) [26] noted that the inorganic film is composed of PbS colloidal quantum dots increased the Sb2Se3 efficiency from 5.42–6.50%. Numerous researchers utilized inorganic copper thiocyanate (CuSCN)-HTL to enhance the PCE of Sb2Se3 cells by 7.5%. The researcher applied the sequence of events standard HTL in several SC's: 9,9-Spirobi-fluorene (Spiro-OMeTAD) and 2,2,7,7-Tetrakis (N,N-di-p-methoxyphenylamine). Additionally, this material was used in Sb2(S, Se)3 -absorber based solar cells, which exhibit the PCE below 10% [17,18]. However, because of their pricey inherent characteristics and unpredictable capabilities of the device, it is not advised to utilize organic HTLs for industrial manufacturing. Therefore, it is necessary for the expansion a brand-novel, non-toxic, reliable, and economical material to produce effective PV cells.

The reason for the frequent usage of this approach in evaluating HTLs' effectiveness in perovskite devices is its straightforward and efficient structure. In addition, BSF layer is a heavily doped section located on the back surface of a SC. To enhance the efficiency and stability of heterojunction solar cells, several inorganic TMOs (transition metal oxide) such as WO3, NiO, V2O5, and CuI have been added as the BSF layer [19,20]. Among these TMOs, V2O5 stands out for several reasons, including excellent climate constancy and powerful optical and electrical properties. A very affordable and easy spin-coating fabrication approach can be used to create the V2O5 film [27]. The utilization of a special SnS2/Sb2Se3/V2O5 combination is important because the SnS2 hole-blocking layer reduces recombination losses at the Sb2Se3/SnS2 interface, while the V2O5 back surface field layer increases the accumulation of the generated charge carriers. When SnS2 and V2O5 are combined with a Sb2Se3 absorber, heightened charge transfer, reduced recombination losses, and improved charge carrier aggregation are generated. Therefore, SnS2/Sb2Se3/V2O5 heterostructure offers effective electron and hole transportation in photoactive layers, leading in enhanced efficiency; and this enables the simulation of a solar cell to perform effectively in a variety of situations [27].

The ETL (n-type), which works as buffer layer, is crucial for the devices' VOC and JSC. The absorber/buffer interaction alignment of the bands has a substantial influence on the VOC. The type of band alignment at the contact can be categorized as the cliff, plane, or spike; based on the conduction band offset (CBO). An interface spike prevents recombination there, whereas cliff type band flexing leads to more interface recombination and reduce VOC levels [28]. However, the spike's height must be adequately low to prevent it from blocking the transport of electrons from the layer of absorber to the layer of buffer; lowering current density and the fill factor [29]. By depositing SnS2 utilizing pulsed laser deposition (PLD) and analysing the high-quality stored SnS2 films optically and electrically, the bandgap, carrier concentration, and electron affinity, in the SnS2 layers were determined. On the other hand, Sb2Se3-based photovoltaic cells have limitations due to assumptions made in simulations that do not accurately represent the intricacies of the actual world. Difficulties in processing materials and possible stability and efficiency problems make it difficult to put suggested solar cell configurations into reality. A major obstacle to increasing production is also obtaining reliable and consistent device performance. All things considered, overcoming these constraints calls for in-depth knowledge as well as creative approaches in the fields of material science and device engineering.

In this paper, the proposed (Al/FTO/SnS2/Sb2Se3/V2O5/Ni) Sb2Se3-based heterojunction TFSC; with BSF and without BSF were studied and its photovoltaic performance characteristics investigated using the SCAPS-1D simulation model. The study analysed various factors, including the device's thickness, carrier concentration, defect density, band alignment, operating temperature, and back SRV, to understand their effects on the SC's performance parameters. The aim was to improve the device's structural efficiency and explore a more cost-effective and efficient photoconversion method.