Synergistic Effects of NiO, Fe3O4, and WO3 Bilayers With Spiro-OMeTAD in CsFAMA Perovskite Solar Cells

Abstract

The selection of appropriate materials for each layer in the device design has a significant impact on the photovoltaic (PV) performance of perovskite solar cells (PSCs). In particular, the hole transport layer (HTL) is responsible for extracting holes from the perovskite layer and transferring them to the relevant electrode. In this work, we investigated the impact of various commercially available dispersions of metal oxide (MO_X) hole transport materials (HTMs) including nickel oxide (NiO), iron oxide (Fe₃O₄), tungsten oxide (WO₃), and Spiro-OMeTAD (as a reference) in a single and bilayer architecture on the PV performance of PSCs. The comparative analysis reveals that the NiO/Spiro combination delivers the best overall performance, achieving a power conversion efficiency (PCE) of 18.21% under optimized conditions. In spite of offering an effective charge extraction, the optimal configuration revealed very low hysteresis, which is essential for the long-term stability and reproducibility of PSCs. The MO_X/Spiro bilayer HTL-based devices exhibited higher PCE, better long-term stability, reduced interfacial trap densities, and higher hole extraction rates in comparison to the reference (pristine Spiro-OMeTAD) devices. These findings suggest that incorporating the MO_X layer between perovskite and Spiro-OMeTAD layers significantly enhances the PV performance and provides further exploration for commercial use.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

1. Introduction

Organic–inorganic lead halide perovskite solar cells (PSCs) have garnered significant interest from the scientific community owing to their unique features, which include high charge carrier mobility, high absorption coefficients, and extended carrier lifetimes [1–4]. The power conversion efficiency (PCE) of PSCs has increased dramatically in only a decade, from 3.8% to 26.1% [5, 6]. Key strategies for enhancing the PCE and long-term stability of PSCs that approach the theoretical Shockley–Queisser limit (33%) include new fabrication techniques, surface defect passivation, compositional engineering, and advanced device architectures [7–9]. To date, the highly efficient PSCs have utilized a regular planar structure (n-i-p), incorporating various organic hole transport layers (HTLs) such as Spiro-OMeTAD, P3HT, and PTAA [10, 11]. Among all, Spiro-OMeTAD has been widely used as a benchmark material in numerous studies due to its optimized energy levels, better solubility, and amorphous character. These attributes enable it to achieve consistent and reproducible efficiencies, irrespective of the fabrication laboratory [12–14]. Achieving high-performance PSCs using Spiro-OMeTAD necessitates the incorporation of dopants such as Li-TFSI and tBP to enhance hole mobility. However, the presence of Li negatively affects the stability of the PSC [15, 16]. In particular, lithium ion diffusion into the perovskite layer is noted resulting in degradation [17, 18].

Recently, inorganic metal oxide (MO_X)–based hole transport materials (HTMs) such as nickel oxide (NiO), tungsten oxide (WO₃), iron oxide (Fe₃O₄), copper oxide (CuO_X), and copper thiocyanate (CuSCN) are considered potentially superior alternatives owing to their high mobility and stability compared to conventional organic HTMs [19–23]. However, the challenges associated with their processing on the absorber layer have severely obstructed efficiency improvements in conventional devices. The MO_X-based HTLs in PSC have exhibited promising results such as long-term stability but with low PCEs [24, 25]. We speculate that using multilayer HTLs instead of a single one would enable us to leverage the complementing characteristics of every individual layer. In order to provide an energy level cascade and the proper surface energies for perovskite layer nucleation, these multilayer architectures allow the selection of HTL pairs with acceptable work functions [26, 27]. Multilayer architecture also helps to avoid charge extraction at inappropriate electrodes, passivate surface defects, and establish concrete obstacles that impede the diffusion of moisture and ions [28, 29]. Moreover, the use of laboratory-synthesized dispersions of MO_X has a detrimental effect on device performance. The laboratory synthesized dispersion often suffers from variation in uniformity, impurities, and scalability and may require additional testing to ensure suitability for long-term use [30–32].

In this work, we investigate the benefit of utilizing commercially available dispersions of MO_X as HTM in PSC. The three most recognized p-type MOXs, NiO, Fe₃O₄, and WO₃, were selected based on their high mobility and perfect energy band level alignments with the absorber layer. The commercial dispersions of MO_X-based HTLs were applied in the regular planar architecture of PSC with single and bilayer configurations to assess their impact on the photovoltaic (PV) performance and stability of PSCs. The commercial dispersions were purchased from well-reputed suppliers. Further, we utilized triple-cation perovskites (CsFAMA) due to their enhanced thermal stability, reduced hysteresis, and superior crystallinity compared to single or double-cation systems. The incorporation of cesium (Cs⁺) improves structural stability, while the synergy of formamidinium (FA⁺) and methylammonium (MA⁺) ensures optimal bandgap and charge transport properties, making them ideal for high-performance PSCs. The results reveal that when used alone, NiO, Fe₃O₄, and WO₃ HTLs exhibit poorer PV performance compared to Spiro-OMeTAD. However, when these materials are used in bilayer configurations with Spiro-OMeTAD, there are notable improvements in performance metrics. The bilayer HTLs demonstrate enhanced PV efficiency, better charge extraction, reduced charge recombination, lower hysteresis, and improved shelf-life stability. The NiO/Spiro HTL-based PSC exhibited outstanding performance among others in comparison.

2. Experiment

2.1. Materials

All chemicals used in this work were sourced from well-reputable suppliers to assure quality and reliability. NiO (2.5 wt.% in ethanol) and WO₃ (2.5 wt.% in 2-propanol) were procured from Avantama. Spiro-OMeTAD and ITO substrates were purchased from Lumtec. FAI and MABr were obtained from Greatcell. Fe₃O₄ nanoparticles (5 mg/mL in toluene) with nanoparticle size (∼10 nm), CsI, PbI₂, and PbBr₂ were purchased from Sigma-Aldrich. Different solvents utilized in this research include DMF, DMSO, ACN, and CB. All electron transport layers (ETLs) were prepared with a dispersion of SnO₂ procured from Alfa Aesar.

2.2. Device Fabrication

Glass substrates covered with ITO were subjected to a chemical etching process using a 2 M HCl solution and Zn powder. After the substrates were etched, they were meticulously cleaned using a series of procedures involving soapy water, distilled water, acetone, and IPA, each of which was left on for 15 min. The substrates were washed thoroughly, dried with a nitrogen stream, and treated with O₂ plasma for 7 min in order to substantiate that any remaining organic materials were completely removed from the ITO surface. After that, 100 μL of SnO₂ was spin-coated for 45 s at 3000 rpm to produce the ETLs, and it was then annealed for 60 min at 150°C. Prior to the perovskite layer being deposited, the ETL-coated ITO substrates underwent a 20-minute UV-ozone treatment. The mixed-halide perovskite (CsFAMA) was produced using the procedures described in our earlier research [33]. The entire deposition process was conducted within an N₂-filled glovebox. Initially, 45 μL of the perovskite precursor solution was spin-coated for 20 s at 1500 rpm, and then for 20 s at 5000 rpm. During this spin-coating stage, 300 μL of CB (acting as an antisolvent) was added to the spinning substrate roughly 10 s before the end of the cycle. The resulting thin films were then annealed at 120°C for 15 min to promote crystallization. Next, the reference HTL, based on a Spiro-OMeTAD dispersion, was deposited over the perovskite layer by spin-coating at 4000 rpm for 40 s. For single and bilayer devices, commercially sourced HTL dispersions (NiO, WO₃, and Fe₃O₄) were also spin-coated atop the perovskite layer at 4000 rpm for 40 s, with a ramp rate of 500 rpm/s. Gold (100 nm) was thermally evaporated under a high vacuum of 8 × 10⁻⁶ mbar. The active area of the PSC was defined using a shadow metal mask during the device fabrication process. The mask, which has a precise opening of 0.133 cm², was used during the thermal evaporation of the gold electrode to ensure that only the defined area of the device was exposed to the metal deposition. This approach ensures accurate measurement of the PV performance by limiting the effective area of the device to 0.133 cm², and it minimizes the influence of edge effects or irregularities in the film deposition process.

2.3. Thin Films and Device Characterization

Their optical properties of thin films were assessed with a Cary 5000 UV-Vis-NIR spectrophotometer. The morphological characteristics of the thin films were examined utilizing a FESEM (Zeiss Gemini 500). The photoluminescence (PL) measurements were conducted with a Pico Quant Fluo Time 300 fluorescence spectrometer endowed with a 404 nm laser. A customized setup was used to record the PSC’s performance data, and it was calibrated using a silicon reference cell supplied by Fraunhofer ISE. A Keithley 2410 source meter was used to measure current-voltage (J-V) characteristics while employing a KG5 filter and simulated AM 1.5 G light. Moreover, the trap density was assessed using space charge limited current (SCLC) measurements.

3. Results and Discussion

In our work, we have selected three different MO_X-based HTMs including NiO, Fe₃O₄, and WO₃ as an efficient electron-blocking layer due to their exceptional mobility and perfect band alignment with the absorber layer. Spiro-OMeTAD was selected as the reference HTL. The three MO_X-based HTLs exhibited significant transmittance, particularly in the visible region as displayed in Figure 1(a). The ITO/NiO, ITO/Fe₃O₄, and ITO/WO₃ thin films all exhibited transmittance above 70% in the 500–600 nm wavelength range, confirming the suitability of these HTLs as charge-selective contacts for the perovskite layer [34]. Figures 1(b), 1(c), and 1(d) reveal the surface morphology of MO_X HTLs deposited atop the ITO substrate. ITO/NiO thin film exhibited smooth surface coverage, and patches of ITO became visible indicating the formation of a very thin layer. ITO/Fe₃O₄ thin film demonstrated a uniform surface coverage with spherical nanoparticles and adopted the ITO surface morphology. Similarly, the ITO/WO₃ thin film also exhibited homogenous surface coverage, and no patch of ITO was noted for the thin film. A pinhole-free formation of thin films was observed for all three MO_X HTLs. The improved morphology can be attributed to the excellent dispersibility of MOXs in the chosen solvents, which may contribute to enhanced performance in PSCs [35].

[figure(s) omitted; refer to PDF]

The absorbance spectra of CsFAMA thin films deposited on ITO/SnO₂ exhibited significant absorption as shown in Figure 2(a). The different absorption curves after depositing single HTLs (Spiro-OMeTAD, NiO, Fe₃O₄, and WO₃) and bilayer HTLs (NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro) atop ITO/SnO₂/CsFAMA surface exhibited identical absorption profiles. Overall, no significant change in absorption profile was noted for single as well as bilayer HTLs. The surface morphology of single and bilayer HTLs was analyzed by SEM. Figure 2(b) shows dense coverage of the perovskite (CsFAMA) thin film atop ITO/SnO₂. The large-size grains with visible grain boundaries were noted for ITO/SnO₂/CsFAMA thin film. The large grain size with visible grain boundaries of perovskite can offer several advantages, such as reduced grain boundary recombination, enhanced charge carrier mobility, and improved overall efficiency in PSCs [36, 37].

[figure(s) omitted; refer to PDF]

Deposition of the Spiro-OMeTAD thin layer on top of CsFAMA is shown in Figure 2(c). Air or oxygen may be able to penetrate the perovskite layer through the many holes in the Spiro-OMeTAD layer, which are probably caused by the addition of Li-TFSI and tBP dopants. This might compromise the stability and PV performance of the PSCs [38]. To overcome this challenge, a thin layer of MO_X (NiO, Fe₃O₄, and WO₃) can be deposited in between the perovskite layer and Spiro layer. Figures 2(d), 2(e), and 2(f) show the surface morphology of commercially synthesized MO_X HTLs deposited atop ITO/SnO₂/CsFAMA thin films. The NiO, Fe₃O₄, and WO₃ layers on the CsFAMA perovskite formed a uniform surface. The pinhole-free surface coverage of interlayers was observed. This smooth overlayer, characterized by lower surface roughness, is more effective in enhancing ohmic contact, which can lead to improved device performance [39].

Figures 2(g), 2(h), and 2(i) show the bilayer HTLs, i.e., Spiro layer deposited atop NiO, Fe₃O_4, and WO₃ MO_X interlayers, respectively. Despite the inclusion of dopants, the MO_X interlayers (NiO, Fe₃O₄, and WO₃) did not exhibit any visible holes, indicating the formation of a more uniform and pinhole-free layer. The presence of the MO_X interlayer helps to create more reliable, effective, and reproducible PSCs [40]. An additional benefit in the form of reduced roughness at the perovskite/HTL interface could be the formation of a uniform and flat MO_X thin film.

The PSCs were fabricated in a regular planar structure using single-layer and bilayer MO_X-based HTLs. The typical single HTL-based device configuration includes ITO/SnO₂/CsFAMA/HTL/Au, whereas Spiro-OMeTAD, NiO, Fe₃O₄, and WO₃ were utilized as HTLs. The annealed perovskite layer was spin-coated with commercial dispersions of NiO, FeO₄, and WO₃. The light J-V curves for PSCs generated with single HTLs are shown in Figure 3(a). According to Table 1, the PSC utilizing the Spiro-OMeTAD HTL obtained a PCE of 15.87%, a $J_{\text{SC}}$ of 22.59 mA·cm⁻², a $V_{\text{OC}}$ of 1.08 V, and an FF of 65.06%. In comparison to the reference device, all MO_X (NiO, Fe₃O₄, and WO₃) HTL-based PSCs exhibited poor PV performance. The NiO, Fe₃O₄, and WO₃ MO_X single HTL-based devices exhibited PCE of 3.58%, 3.55%, and 2.76%, respectively. The PSCs based on a single HTL exhibited low V_OC and FF indicating a higher recombination in the devices. To gain a deeper understanding of the underlying mechanism, we also measured the J-V curves of the PSCs under dark conditions, as shown in Figure 3(b). Compared to the pure Spiro HTL, the MO_X (NiO, Fe₃O₄, and WO₃) HTLs enhanced charge extraction, as indicated by the higher injected current. However, the single MO_X HTLs exhibited higher leakage current attributed to the formation of a thin layer. This elevated leakage current, due to the extremely thin film, results in increased recombination in the MO_X HTL-based PSCs.

[figure(s) omitted; refer to PDF]

Table 1

Photovoltaic characteristics of PSCs using single HTL.

Device configuration	$J_{\text{SC}}$ (mA·cm−2)	$V_{\text{OC}}$ (V)	FF (%)	PCE (%)
ITO/SnO2/CsFAMA/Spiro/Ag	22.59	1.08	65.06	15.87
ITO/SnO2/CsFAMA/WO3/Ag	15.07	0.53	34.56	2.76
ITO/SnO2/CsFAMA/NiO/Ag	20.37	0.46	38.24	3.58
ITO/SnO2/CsFAMA/Fe3O4/Ag	18.06	0.49	40.17	3.55

Figures 4(a), 4(b), 4(c), and 4(d) present cross-sectional SEM images of complete PSCs utilizing pristine Spiro HTL and bilayer HTLs (NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro), while the J-V curves of the best-performing devices are shown in Figures 4(e), 4(f), 4(g), and 4(h). The PV parameters are summarized in Table 2. The bilayer devices demonstrated superior PV performance compared to the reference devices. Among them, the NiO/Spiro bilayer HTL-based PSC exhibited the higher PCE of 18.21% ($J_{\text{SC}}$ = 21.98 mA·cm⁻², $V_{\text{OC}}$ = 1.13 V, and FF = 73.14%) in reverse scan, outperforming the Fe₃O₄/Spiro (PCE = 17.88%, $J_{\text{SC}}$ = 22.06 mA·cm⁻², $V_{\text{OC}}$ = 1.12 V, and FF = 71.81%) and WO₃/Spiro (PCE = 17.81%, $J_{\text{SC}}$ = 22.39 mA·cm⁻², $V_{\text{OC}}$ = 1.12 V, and FF = 70.81%) based PSCs. Further, the hysteresis index (HI) for bilayer devices was observed to be significantly reduced as compared to reference devices affirming the more reliable PCEs. The enhancement in PCE is primarily due to a higher $V_{\text{OC}}$ observed in all bilayer devices. One can note that using a single MO_X HTL in PSC resulted in poor $V_{\text{OC}}$. However, when integrated with Spiro-OMeTAD in a bilayer HTL, the combined configuration harnesses the advantages of both HTMs, specifically the electron blocking attributes of Spiro-OMeTAD and the fast charge extraction/transport features of MO_X HTLs (NiO, Fe₃O₄, and WO₃).

[figure(s) omitted; refer to PDF]

Table 2

Photovoltaic characteristics of PSCs using pristine Spiro and metal oxide-based bilayer HTLs.

HTL	Scan direction	$J_{\text{SC}}$ (mA·cm−2)	$V_{\text{OC}}$ (V)	FF (%)	PCE (%)
NiO/Spiro	RS	21.98	1.13	73.14	18.21
	FS	20.64	1.13	71.00	16.60
Fe3O4/Spiro	RS	22.06	1.12	71.81	17.88
	FS	20.10	1.12	72.32	16.34
WO3/Spiro	RS	22.39	1.12	70.81	17.81
	FS	22.66	1.12	63.89	16.23
Spiro	RS	22.18	1.12	71.30	17.84
	FS	20.53	1.09	67.10	15.10

We performed various analyses to shed light on how the MO_X layers affect device performance. We examined the steady-state and transient PL decay to reveal the hole extraction capacity of MO_X HTLs. Figure 5(a) exhibits PL (steady state) spectra of CsFAMA thin films deposited atop ITO/SnO₂, single layer, and bilayer HTLs deposited atop ITO/SnO₂/CsFAMA. The perovskite manifested a strong and sharp emission peak centered at 760 nm which is in good agreement with previous reports [41]. After depositing NiO, Fe₃O₄, and WO₃ onto CsFAMA thin film, a drop of 18.7%, 17.1%, and 55.1% in PL intensity was observed. The drop in PL intensity is indicative of efficient charge extraction by these aforementioned HTLs. Similarly, a slight blue shift in NiO-based thin film was noted and can be attributed to the filling of trap states. Furthermore, with bilayer HTLs (NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro) deposited atop CsFAMA, a drop of 95.2%, 94.3%, and 98.5% in PL intensity was observed. In comparison to the unmodified perovskite, applying bilayer MO_X HTLs onto the surface of the perovskite caused an immediate drop (peak quenching) in PL intensity, suggesting improved charge extraction from the perovskite layer.

[figure(s) omitted; refer to PDF]

To further investigate the charge transport dynamics, a biexponential decay function was used to evaluate time-resolved photoluminescence (TRPL) curves: function $ft=A_1\exp -\mathrm{t}/{\tau }_1+A_2\exp -\mathrm{t}/{\tau }_2$, and average lifetime was calculated by ${\tau }_{\text{ave}}=\sum A_i{\tau }_i^2/\sum {A_i\tau }_i$, as shown in Figure 5(b) [42]. The fitting parameters are provided in Table 3, where ${\tau }_1$ and ${\tau }_2$ correspond to the fast and slow decay components, respectively. Radiative recombination–induced charge carrier relaxation is the major source of the slow decay component ${\tau }_2$, whereas the charge extraction layer and perovskite film defects are principally responsible for the quick decay component ${\tau }_1$. We are very interested in the fast decay component ${\tau }_1$ in this work. The CsFAMA deposited onto NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro thin films exhibited ${\tau }_1$ of 0.54, 1.02, and 0.81 ns with an amplitude ($A_1$) of 99.72%, 98.48%, and 98.98%. The fast charge carrier extraction is noted for bilayer HTL thin films as compared to pristine Spiro-based thin films. Further, we noted the smallest value of the fast decay component with NiO/Spiro-based sample confirming the most optimal MO_X for bilayer architecture with fast charge extraction. The results are consistent with the PV measurements discussed earlier. To get further insights about interfacial trap densities, SCLC measurements were performed as shown in Figure 5(c). The complete details of the mechanism are described in our previous work [43]. The trap-filled limited voltage ($V_{\text{TFL}}$) values from SCLC curves for Spiro, NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro-based devices were measured to be 0.14, 0.11, 0.09, and 0.28 V, respectively. The $n_t$ values for Spiro, NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro-based devices were calculated to be 1.61 × 10¹⁶, 1.26 × 10¹⁶, 1.03 × 10¹⁶, and 3.22 × 10¹⁶ cm⁻³, respectively. The low values of trap density for NiO/Spiro and Fe₃O₄/Spiro-based devices are indicative of fewer traps in the bilayer HTL favorable for efficient hole extraction.

Table 3

PL decay components.

Description (ITO/SnO2)	${\tau }_1$ (ns)	$A_1$ (%)	${\tau }_2$ (ns)	$A_2$ (%)	${\tau }_{\text{ave}}$ (ns)
CsFAMA	6.55	50.42	141.90	49.58	73.66
CsFAMA/Spiro	1.55	92.17	14.59	7.83	2.57
CsFAMA/NiO	4.60	55.61	164.06	44.39	75.39
CsFAMA/NiO/Spiro	0.54	99.72	8.01	0.28	0.56
CsFAMA/Fe3O4	9.74	33.31	66.09	66.69	47.32
CsFAMA/Fe3O4/Spiro	1.02	98.48	31.69	1.52	1.49
CsFAMA/WO3	6.13	38.48	26.89	61.52	18.90
CsFAMA/WO3/Spiro	0.81	98.98	17.21	1.02	0.98

We also assessed the shelf life of PSCs using bilayer HTLs compared to the pristine Spiro-OMeTAD HTL, as depicted in Figure 5(d). The measurements were performed inside a glovebox, and the devices were stored for 1000 h. The bilayer devices employing NiO/Spiro, Fe₃O₄/Spiro, and WO₃/Spiro HTLs exhibited better long-standing stability by retaining 91%, 87%, and 85% of initial PCE, respectively. However, the reference devices retained 80% of the initial PCE. The enhanced stability of bilayer devices rises due to favorable interlayer of MO_X in between perovskite and Spiro, thus preventing the diffusion of dopants to the perovskite layer. Further, the NiO/Spiro-based device exhibited superior stability among others suggesting NiO HTL as a best choice in PSCs. Table 4 demonstrates recently published work on inorganic HTLs, particularly in bilayer configuration. Further optimization of these potential MO_X bilayer HTLs can resolve the interfacial energy alignment issues and minimize charge recombination, ultimately enhancing the efficiency and stability of the PSCs.

Table 4

Comparison with recently published work on inorganic HTLs in bilayer configuration.

HTL type	Configuration	PCE (%)	$J_{\text{SC}}$ (mA/cm2)	$V_{\text{OC}}$ (V)	FF (%)	Reference
CuI/CuSCN	Bilayer	20.35	20.26	1.10	78.0	[44]
CuI/PEDOT	Bilayer	15.75	28.50	0.75	73.7	[45]
PTAA/CuI	Bilayer	19.43	23.98	1.05	76.7	[46]
CuI/Spiro	Bilayer	17.30	20.05	1.12	77.1	[47]
FeOX/Spiro	Bilayer	16.7	20.00	1.14	73.4	[43]
NiO/Spiro	Bilayer	18.21	21.98	1.13	73.14	This work
Fe3O4/Spiro	Bilayer	17.88	22.06	1.12	71.81	This work
WO3/Spiro	Bilayer	17.81	22.39	1.12	70.81	This work

4. Conclusion

This study demonstrates the significant impact of commercially synthesized MO_X HTL dispersions on the performance of PSCs. The comparative analysis of HTL materials in PSCs reveals that the NiO/Spiro combination delivers the best overall performance, achieving a PCE of 18.21% under optimized conditions with shelf-life stability of 91% up to 1000 h. A significant decrease in trap density was also observed with bilayer configuration. The MO_X/Spiro-OMeTAD bilayer configuration not only provides an efficient charge extraction but also demonstrates relatively low hysteresis, which is crucial for the long-term stability and reliability of solar cells. The findings of this study suggest that NiO is a beneficial HTM for the fabrication of high-performance PSCs and demands further investigation for commercial applications.

Ethics Statement

This article does not contain any studies with human participants or animals performed by any of the authors.

Disclosure

This article has not been published by another journal.

Author Contributions

M.A.J. contributed to conceptualization, experimental design, and writing the original draft. A.A.Q. worked on methodology, experimental design, and supervision. M.U.A. assisted in experimental work, data validation, and manuscript preparation. H.M.N. handled data acquisition and formal analysis. M.A. provided resources and secured funding. A.K. played a significant role in the revision process, offering critical feedback, refining data interpretation, and assisting with manuscript revisions to meet journal requirements.

Funding

No financial support was received to complete the present research work.

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