Enhanced Efficiency of CZTS Solar Cells with Reduced Graphene Oxide and Titanium Dioxide Layers: A SCAPS Simulation Study

Abstract

Copper zinc tin sulfide (commonly known as CZTS) solar cells (SCs) are gaining attention as a promising technology for sustainable electricity generation owing to their cost-effectiveness, availability of materials, and environmental advantages. The goal of this study is to enhance CZTS SC performance by adding a back surface field (BSF) layer. SC capacitance simulator software (SCAPS) was used to examine three different configurations. Another option is to replace the cadmium sulfide (CdS) buffer layer with a titanium dioxide (TiO₂) layer. The results demonstrate that the reduced graphene oxide (rGO) BSF layer increases the conversion efficiency by 25.68% and significantly improves the fill factor, attributed to lowering carrier recombination and creating a quasi-ohmic contact at the interface between the metal and semiconductor. Furthermore, replacing the CdS buffer layer with TiO₂ offers potential efficiency gains and mitigates environmental concerns associated with the toxicity of CdS. The results of this investigation could enhance the efficiency and viability of CZTS SCs for future energy applications. However, it is observed that BSF layers may become less effective at elevated temperatures due to increased recombination, leading to reduced carrier lifetime. This study underlines valuable insights into optimizing CZTS SC performance through advanced material choices, highlighting the dual benefits of improved efficiency and reduced environmental impact.

1. Introduction

Solar cells (SCs) are pivotal in transitioning towards cleaner and more sustainable energy sources, offering renewable energy generation, reducing reliance on fossil fuels, and enabling cost-effective energy production. Among the various photovoltaic technologies, thin-film technologies, including copper zinc tin sulfide (CZTS) SCs, are gaining prominence due to their photovoltaic efficiency and straightforward fabrication process [1,2,3,4,5,6,7], flexibility [8], and suitability for applications such as building-integrated photovoltaics [9,10,11] and portable electronics [12].

CZTS, alongside other thin-film SC technologies like CdTe [13,14], silicon [15], organic photovoltaic [16,17], perovskite [18,19,20,21,22], and tin sulfide (SnS) SCs [23], offers several advantages, including lightweight construction, flexibility, and the potential for low-cost, high-throughput manufacturing. The use of zinc (Zn) and tin (Sn) in CZTS, instead of the expensive and less abundant indium (In) and gallium (Ga), reduces production costs and supply competition [24,25]. Additionally, CZTS has fewer safety and health concerns, making it a more sustainable option for efficient SCs [26,27]. During CZTS deposition, Mo, which is often used as a back contact layer in thin-film CSs, can react with sulfur (S) to form molybdenum disulfide (MoS₂) [28,29]. An interface free of MoS₂ forms a Schottky diode, creating carrier flow barriers and resulting in resistive losses. Conversely, a CZTS/MoS₂/Mo structure exhibits ohmic behavior due to MoS₂’s semiconductor properties and the band gap of MoS₂ decreases from 1.9 to 1.61 eV [30,31], facilitating ohmic contact. Monolayer MoS₂ has a direct band gap of about 1.9 eV, while multilayer or bulk MoS₂ has an indirect band gap of around 1.2–1.6 eV. The transition from monolayer to multilayer reduces the band gap due to interlayer interactions and changes in electronic structure. If the MoS₂ layer is too thick, it can form a barrier that prevents efficient charge extraction. This thickness limits charge mobility and reduces the device’s overall performance [32]. The back surface field (BSF) layer further reduces the barrier height or width, enhancing carrier flow. This study introduces reduced graphene oxide (rGO) as the BSF layer, aiming to enhance the efficiency of carrier flow and significantly improve the overall performance of the SCs. rGO was selected for its exceptional combination of electrical, optical and mechanical properties. In addition to its high thermal stability as it can withstand higher temperatures, rGO also offers excellent electrical conductivity and high carrier mobility, which are crucial for reducing recombination losses and enhancing charge carrier collection at the back interface [33]. Furthermore, rGO is cost-effective, scalable, and environmentally friendly, making it a sensible option for extensive production [34].

Despite these advantages, traditional CZTS SCs use CdS as a buffer layer, raising significant environmental and health concerns due to cadmium toxicity [35,36]. CdS poses risks during production, operation, and disposal, highlighting the need for safer and more sustainable alternatives. In this context, TiO₂ has emerged as a promising alternative buffer layer [37,38]. TiO₂ is non-toxic [39], abundant, and exhibits excellent optoelectronic properties [40], making it an ideal candidate for creating safer and more environmentally friendly SCs. Several methods can be used to grow TiO₂ films; however, considering the cost-effectiveness, the adhesion property and film quality, atomic layer deposition (ALD) and magnetron sputtering are often the preferred methods for achieving TiO₂ films with optimal properties [37,41]. TiO₂’s wide bandgap (~3.2 eV) [42] minimizes parasitic absorption, enhancing overall efficiency through improved light trapping and photon absorption. TiO₂ has favorable electron affinity and excellent charge transport characteristics, minimizing interface recombination and enabling effective electron extraction [43].

To the best of our knowledge, this is the first study underlying a numerical investigation on the suitability of both rGO as BSF and TiO₂ buffer layer for CZTS SCs. A comparison with CZTS SCs using a conventional CdS buffer layer is also provided. A detailed study is carried out on the optimization of different key factors (thickness, electron mobility, defects density, etc.) that would enhance the performance of new SC structures based on CZTS/TiO₂/ZnO:Al with rGO BSF, highlighting the dual benefits of improved efficiency and reduced environmental impact. Most of the parameters used in this numerical study were derived from our previous experimental work, where CZTS/TiO₂/ZnO:Al and CZTS/CdS/ZnO:Al used as the reference SC were both fabricated and tested. Specifically, a vapor-phase deposition approach was employed for most layers, where CZTS was deposited via co-sputtering, TiO₂ through atomic layer deposition (ALD), and ZnO:Al using magnetron sputtering [32]. In contrast, CdS was synthesized using a liquid-phase chemical bath deposition (CBD) method, utilizing cadmium acetate (Cd(CH₃COO)₂), thiourea (SC(NH₂)₂), ammonium chloride (NH₄Cl), and ammonia (NH₃) at a bath temperature of 75 °C [13,44]. The parameters for rGO were adopted from references [45,46]. It is important to note that the reduction process of rGO, typically performed via chemical or thermal reduction, plays a crucial role in determining the quality of the synthesized rGO [46].

This research aims to predict and enhance CZTS CS effectiveness by optimizing the CZTS absorber layer, rGO as a BSF, and TiO₂ buffer layer parameters. With capacitance simulator software SCAPS, using Poisson’s equation and carrier transport principles will assess crucial factors such as steady-state energy band diagrams, interface recombination, and carrier transport dynamics. The optimization process will focus on key factors such as quantum efficiency, electron affinity, bandgap, and device temperature, all aimed at improving the overall performance of CZTS SCs and advancing renewable energy generation.

2. Materials and Methods

2.1. Simulation of the Proposed Configuration

SCAPS is a popular software tool that helps to simulate and analyze how semiconductor devices work. It achieves this by solving key equations from semiconductor physics, like Poisson’s equation, continuity equation, and drift–diffusion equation. Figure 1 displays a flowchart of the SCAPS-1D simulation steps. These equations explain how charge carriers, which are electrons and holes, act when affected by electric fields and temperature. Poisson’s equation can be written as follows:

$${\displaystyle \frac{d^2\mathsf{\psi }(x)}{d{x}^2}}={\displaystyle \frac{e}{{\epsilon }_0{\epsilon }_r}}\left(x\right)-n(x)+N_D-N_A+{\rho }_p-{\rho }_n$$

(1)

where ψ represents the electrostatic potential (V), ρ denotes the charge density (C/m³), N_A (m⁻³) and N_D (m⁻³) refer to the densities of acceptors and donors (m⁻³), respectively, e stands for the elementary charge (1.6 × 10⁻¹⁹ C), ε₀ is the permittivity of free space (F/m), εᵣ(x) signifies the relative permittivity (or dielectric constant), and n(x) indicates the concentration of carriers (m⁻³).

The continuity equations for electrons and holes are specified as follows [45]:

$$-{\displaystyle \frac{1}{q}}{\displaystyle \frac{J_n}{d_x}}=G-R$$

(2)

$$-{\displaystyle \frac{1}{q}}{\displaystyle \frac{J_p}{d_x}}=G-R$$

(3)

where J_n and J_p are for electron and hole currents, q is the charge (Coulomb, C), G is the rate of producing electron–hole pairs, and R is the rate of recombining these pairs. The current densities for electrons and holes (A/m²) can be written as follows:

$$J_n=D_n{\displaystyle \frac{dn}{dx}}+{\mu }_{n}n{\displaystyle \frac{d\Phi }{dx}}$$

(4)

$$J_p=D_p{\displaystyle \frac{dn}{dx}}+{\mu }_{p}p{\displaystyle \frac{d\Phi }{dx}}$$

(5)

where µ_n and µ_p are the mobilities of electrons and holes (cm²/Vs), D_n and D_p are the coefficients for electron and hole diffusion (m²/s), and ϕ refers to the electrostatic potential. SCAPS uses numerical techniques to forecast how semiconductor devices behave, using material properties, shape, and boundary conditions as inputs, and it provides electrical features such as I-V and C-V curves as outputs.

Configurations

• Conventional CZTS SC without BSF Layer.

This configuration represents a traditional CZTS SC structure without additional layers to reduce recombination losses at the back contact.

2.

CZTS SC with rGO BSF Layer.

A CZTS SC structure is modified in this configuration by incorporating an rGO BSF layer. The rGO layer aims to enhance SC performance by reducing recombination losses at the back contact.

3.

CZTS SC with TiO₂ Buffer Layer:

The CZTS SC structure is further modified by replacing the CdS buffer layer with a TiO₂ buffer layer. The TiO₂ buffer layer aims to improve SC performance by minimizing recombination losses at the buffer–absorber interface.

Figure 2 shows three types of CZTS SC structures: Figure 2a displays a standard structure that does not have a BSF layer, Figure 2b exhibits a structure with an rGO BSF layer, and Figure 2c shows a structure with a titanium dioxide (TiO₂) buffer layer. The rGO and TiO₂ layers improve SC efficiency by serving as BSF layers between the solar absorber and the back metal contact or buffer–absorber interface. The bandgap of rGO changes based on how it is made and its reduction level. Typically, GO has a larger bandgap than graphene because oxygen-containing groups hinder the lattice structure of graphene. rGO eliminates some of these groups and restores the lattice structure, which lowers the bandgap. GO generally has a bandgap around 2.2 eV [45], while rGO shows a bandgap between 1.00 and 1.69 eV [45,46,47], depending on the reduction process. An rGO bandgap of 1.09 eV is commonly used [48].

2.2. Material Parameters

Numerical simulations, especially with the SCAPS program, have been important for improving our knowledge of chalcogenide-based SCs. SCAPS uses basic semiconductor physics formulas, like continuity equations for electrons and holes and Poisson’s equation. It allows for a significant level of customization in parameters, such as bandgap, electron affinity, mobility, and doping, among others. There are different lighting spectra to choose from, like AM0, AM1.5D, and monochromatic, along with standard test conditions (STCs) such as global air mass (AM 1.5G), 300 K, and 1000 W/m² of light power. The characteristics of the layers used for the simulated SCs are shown in

Table 1. Parameters of simulation used in the layers of SCs.

Parameters	Layer Material
	CZTS [44]	CdS [13]	ZnO [49]	Al:ZnO [50]	rGO [45,46,51]	TiO2 [37,52,53]
Thickness (µm)	0.5–3	0.05–0.15	0.07	0.35	0.2–1	0.05–0.15
Bandgap (eV)	1.43	2.4	3.4	3.4	1.09	3.2
Electron affinity (eV)	4.2	4.4	4.6	4.6	3.2	4.2
Dielectric permittivity	7	10	9	9	10	10
CB density of states (cm−3)	2.2·1018	2.2·1018	2.2·1018	2.2·1018	2.2·1018	2.2·1018
VB density of states (cm−3)	1.8·1019	1.8·1019	1.8·1019	–	2·1018	1.8·1019
Electron/hole mobility (cm2V−1s−1)	5–6/25	100/25	100/25	100/25	320/123	100/25
Electron thermal velocity (cm/s)	107	107	107	107	–	107
Hole thermal velocity (cm/s)	107	107	107	107	–	107
Shallow uniform donor density ND (cm−3)	0	1015	1015	1015	1015	1015
Shallow uniform acceptor density NA (cm−3)	1·1015–1.8·1016	–	–	–	2·1018	–

.

3. Results

3.1. Part I: Conventional CZTS SC

SCAPS was used to look at how making the absorber layer thinner affects the photoelectrical features of CZTS SCs. The numerical results also showed how adding rGO and TiO₂ as BSF or buffer layers influences the performance of the device. The research examined the effects of changing the thickness of the CZTS and BSF layers, along with the role of temperature on the SC’s photovoltaic properties.

3.1.1. Thickness Optimization of the CZTS Absorber Layer

This part looks at how ZnO/CdS/CZTS SCs perform with different thicknesses of the CZTS absorber layer, based on the details in Table 1. The main aim is to find the best absorber layer thickness for these cells. Figure 3 illustrates the variations in the fill factor (FF), open-circuit voltage (V_OC), short-circuit current density (J_SC), and efficiency (η) as the p-CZTS absorber layer thickness changes from 0.5 to 3 µm. The FF reaches its highest point around 1.5 µm before slowly declining. J_SC progressively increases with thickness, reaching a plateau beyond 2 µm, indicating increased photon absorption and electron-hole pair production, with diminishing returns thereafter. V_OC exhibits a quick initial rise and gradual stabilization beyond 2 µm, indicating lower recombination rates at the CZTS–Mo interface in thicker films. Efficiency climbs from 13% to 19.87% as thickness grows from 0.5 µm to 3 µm, with a strong rise up to around 1 µm. More gradually, it stabilizes beyond 2 µm, suggesting no substantial change in efficiency. So. the increase in J_SC and V_OC improved overall efficiency.

As an illustration, at a CZTS thickness level of 1 µm, the device conversion efficiency increases by 16.98% with the Mo layer [54]. Therefore, an optimal thickness of 1 µm to 2 µm is recommended for the p-CZTS absorber layer to balance all performance parameters effectively.

3.1.2. Quantum Efficiency of the CZTS Layer with Various Thicknesses

Figure 4 shows the quantum efficiency (QE) of a material as a function of wavelength, ranging from 300 to 1200 nm, for different absorber layer thicknesses. There are five solid curves and one dashed curve, each corresponding to different thicknesses of the absorber layer: 0.5 µm (black), 1 µm (red), 1.5 µm (green), 2 µm (yellow), 2.5 µm (blue), and 3 µm (purple). All curves show a similar trend, with QE increasing sharply at shorter wavelengths, peaking, and then gradually decreasing at longer wavelengths. Thinner layers, like the 0.5 µm curve, show the lowest QE, while thicker layers, particularly around 2 to 2.5 µm, show the highest and most stable QE across the wavelength range. Beyond 2.5 µm, the improvements in QE are marginal, indicating diminishing returns. Notably, there is no significant change in QE beyond a thickness of 2.5 µm, suggesting that increasing the thickness further does not substantially enhance performance.

3.1.3. Current Flow (J) Related to Voltage (V)

Figure 5 displays the current density (J) as a function of voltage (V). Initially, the current density remains around zero until around 0.60 Volt, suggesting limited current flow. Around 0.60 Volt, a rapid rise in current density indicates the start of considerable current flow when the device approaches its threshold voltage. Beyond this threshold, the current density significantly increases, indicating a significant link between voltage and current density at higher voltages.

3.1.4. Impact of Electron Mobilities and Total Defect Density of the Absorber Layer

Figure 6 shows the relationship between electron mobility and η of a material, likely in the context of a semiconductor or electronic device. The plot indicates that as the electron mobility increases from 5 cm²/Vs to 6 cm²/Vs, the efficiency of the device or material also increases, although the increase is slight. The efficiency starts around 20.54% and gradually decreases to just above 20.50% as electron mobility improves.

This shows that increased electron mobility improves the device’s efficiency, even if the gain is slight. The pattern suggests that increasing electron mobility can improve performance, but efficiency improvements may plateau beyond specific mobility values.

The overall defect density in the active layer is another important element that can greatly influence how well the device works. The performance of thin-film SCs relies on how good the interfaces are and the presence of defects like point defects, dislocations, stacking faults, and grain boundaries [55]. Defects in the absorber layer that cause a greater frequency of pinholes and recombination result in accelerated film deterioration, decreased stability, and lower device performance overall. The efficiency of the device is impacted by carrier recombination, which is increased by increased defect density.

Figure 7 depicts the link between the overall defect density and efficiency. The graph shows a decreasing trend, demonstrating that as overall defect density grows, efficiency falls. As defect density rises, efficiency decreases from approximately 20% to 18%.

3.2. Part 2: CZTS with BSF Layer (rGO)

Figure 8 shows that introducing a BSF to the SC increases its performance, especially at a thickness of 1.0 µm. At this thickness, the η increased from 16.98% without BSF to around 24.97% in the presence of rGO. Similarly, the V_oc is consistently higher with BSF (about 0.97 V) than without it (0.68 V). BSF stabilizes the J_sc at around 32.66 mA/cm², slightly higher than the 31.67 mA/cm² compared to CZTS without rGO. The FF decreases significantly with BSF, from 82.96% at 0.5 µm to 73.34% at 3 µm, while remaining stable at roughly 79% in the absence of BSF. As a result, BSF improves current and voltage while decreasing FF as thickness grows.

Figure 9 compares the quantum efficiency spectra of CZTS SCs with and without a BSF layer. QE is significantly improved throughout the wavelength range when the BSF layer is present. At 550 nm, the device reaches a high efficiency of around 94%, whereas the device without the BSF reaches a peak of about 84%. This enhancement is because the BSF layer increases photon absorption and electron–hole pair formation by reflecting unabsorbed photons back into the CZTS absorber layer. This effect is most noticeable in the wavelength range of 500 to 1000 nm, when the device with the BSF retains a significantly higher QE, indicating better production of charge carriers and light harvesting. The QE of both devices decreases as the wavelength of the photons absorbed by the CZTS material increases, which indicates the technology’s inherent limitations. The results highlight the crucial function of the BSF layer in maximizing the visible to near-infrared spectrum response of CZTS SCs, which greatly improves the devices’ overall efficiency and performance.

Figure 10 demonstrates the J-V characteristic curve comparison of CZTS solar cells (SCs) with and without a BSF. The addition of a BSF (red curve) improves open-circuit voltage (Voc) and current density, indicating enhanced charge collection and reduced recombination losses. In contrast, the CZTS cell without a BSF (black curve) exhibits lower Voc and increased recombination losses. This confirms that incorporating a BSF enhances device performance by improving carrier transport and minimizing recombination.

Figure 11 shows how adjusting the thickness of the rGO layer affects the performance parameters of CZTS SCs, including FF, J_sc, V_oc, and overall η. The FF slightly declines from 79.41% at 0.2 µm to 78.13% at 1 µm, indicating a minor negative effect as rGO thickness increases. Conversely, Jsc improves from 32.49 mA/cm² to 32.55 mA/cm², and V_oc rises from 0.97 V to 0.99 V over the same thickness range, suggesting enhanced photon absorption and charge separation. These gains lead to an overall efficiency increase, demonstrating that thicker rGO layers enhance SC performance, despite the slight reduction in FF. Notably, beyond a thickness of 0.5 µm, the performance metrics show minimal change, indicating that further increases in rGO thickness offer diminishing returns on performance enhancements.

3.3. Part 3: CZTS SC with TiO₂ Buffer Layer

Figure 12 shows that for CZTS SCs with CdS and TiO₂ buffer layers, η initially increases with thickness, peaking around 26% for TiO₂ and 25.50% for CdS, before gradually decreasing. TiO₂ consistently provides higher V_oc than CdS, with V_oc decreasing from about 1.025 V to 1.005 V for TiO₂ and from 1.015 V to 1.000 V for CdS as thickness increases. Both buffer layers yield similar J_sc, stabilizing around 33 mA/cm². However, CdS exhibits a slightly higher FF, decreasing from 82% to 72%, compared to TiO₂. TiO₂ offers better efficiency, mainly thanks to the increased V_oc, while CdS has a marginally higher FF. Additionally, Nisika reported on the TiO₂ conductivity connected to oxygen vacancies, which has a significant impact on charge extraction and enhances it in the presence of reduced oxygen levels [56,57]. It is suggested to introduce controlled oxygen vacancies in TiO₂ to enhance charge extraction and improve overall device performance. Optimizing the oxygen vacancy concentration could increase V_oc and efficiency in CZTS SCs further.

Figure 13 shows that for SCs with a BSF, as the buffer layer thickness increases from 0.05 µm to 0.15 µm, the η decreases from about 26% to 24% for TiO₂ and from 25.50% to 23.50% for CdS. The V_oc was approximately 1.02 V for TiO₂ and 1.02 V for CdS. The J_sc decreases from around 31.80 mA/cm² to 29.80 mA/cm² for TiO₂ and from 31.60 mA/cm² to 29.50 mA/cm² for CdS. The FF shows a slight decrease from 79.56% to 79.30% for TiO₂ and 79.40% to 79.10% for CdS. From an experimental perspective, few studies have been published, but recently, highly promising findings have been generated [58,59]. This study pioneers a Cd-free superstrate configuration, achieving a record efficiency of 9.7% for ultrathin (Cu,Ag)₂ZnSn(S,Se)₄ SCs with a TiO₂ buffer layer to enhance performance.

Figure 14 shows the temperature-dependent performance study of CZTS SCs with TiO₂ and CdS buffer layers. As the temperature rises, both buffer layers’ efficiency and V_oc drop. TiO₂ has an initial efficiency of 26% at 300 K and decreases to 21.50% at 370 K. CdS has a lower efficiency of roughly 25% and decreases to 21.50% at the same temperature. This graph highlights TiO₂’s higher efficiency and a slower rate of decrease compared to CdS. TiO₂ maintains higher V_oc values over the temperature range, reducing from 1.01 V to 0.89 V, whereas CdS decreases from 0.97 V to 0.88 V. Although both materials have reasonably steady J_sc, CdS has a higher J_sc (32.48 mA/cm²) than TiO₂ (31.73 mA/cm²). However, the fill factor (FF) decreases with temperature. CdS and TiO₂ initially have a FF (79% at 300 K), but both fall to 76.50% and 75.62%, respectively, at 370 K. TiO₂ outperforms CdS in terms of efficiency, V_oc, thermal stability, and resilience. Despite slightly higher FF, CdS cannot match TiO₂’s performance throughout temperature ranges.

Figure 15 compares the current density–voltage (J-V) characteristic among three CZTS-based SC configurations: standard CZTS and CZTS with a BSF, and CZTS with a TiO₂ layer. The figure shows that adding BSF and TiO₂ improves the cells’ performance, as both configurations exhibit higher V_oc than standard CZTS. The improved V_oc suggests better overall performance for the modified configurations, especially for CZTS with TiO₂, which shows the highest V_oc.

Table 2. Performance CZTS SCs with various configurations: FF, V_oc, J_sc, and efficiency.

	Voc (v)	Jsc (mA\cm2)	FF (%)	Efficiency (%)
CZTS/CdS	0.70	33.72	78.44	18.42
CZTS with BSF/CdS	0.97	32.49	77.15	25.01
CZTS/TiO2	1.02	32.65	77.06	25.68

shows that the effectiveness of CZTS SCs is significantly improved by incorporating TiO₂ and a BSF. The J_sc slightly decreases from 33.72 mA/cm² (standard CZTS) to 32.49 mA/cm² (CZTS with BSF) and 32.65 mA/cm² (CZTS with TiO₂). However, the Voc increases significantly, from 0.70 V (standard CZTS) to 0.97 V (with BSF) and 1.02 V (with TiO₂).

Although the FF remains relatively stable, with slight decreases from 78.44% (standard CZTS) to 77.15% (BSF) and 77.06% (TiO₂), the overall η improves considerably. The efficiency rises from 18.42% (standard CZTS) to 25.01% (BSF) and 25.68% (TiO₂), indicating that the TiO₂ configuration provides the best performance enhancement.

4. Conclusions

The theoretical modeling of CZTS SCs with an rGO BSF and TiO₂ as a buffer layer has demonstrated promising advancements in SC efficiency. By precisely tuning the composition and thickness of these layers, this study achieved a predicted efficiency of 25.68%, significantly outperforming conventional SCs. The rGO BSF layer effectively reduced back surface recombination and created a quasi-ohmic contact, contributing to enhanced performance. Moreover, replacing the conventional CdS buffer layer with non-toxic TiO₂ further improved the cell’s overall efficiency to 25.68% while offering a more environmentally sustainable solution.

The success of this modeled structure underscores the potential of advanced materials like rGO and TiO₂ in pushing the limits of thin-film photovoltaic technologies. This research highlights the pivotal role of BSF layers and opens new avenues for developing high-efficiency, eco-friendly SCs, contributing to the future of renewable energy solutions.