FTO Substrate Research Articles

Harnessing the Potential of Morphologically Tailored ZnSn(OH)6 Nanograss Photoanode for Solar‐Driven Water Splitting

AbstractHydrothermal growth of ZnSn(OH)6 nanograss on ZnO‐coated FTO substrates is demonstrated. Effect of surfactants addition (polyvinylpyrrolidone and polyethylene glycol), precursor concentration, and reaction temperature on surface morphology of ZnSn(OH)6 nanograss are investigated. Addition of surfactant in precursor solution results in growth of approximately 20–30 nm thick nanograss morphology with varying orientation. The nanograss grow longer by increasing the concentration of precursors solution. The grown ZnSn(OH)6, exhibits XRD peaks corresponding to cubic phase ZnSn(OH)6. Optical bandgap of the grown nanograss are calculated in the range from ∼3.0 to 3.5 eV. The nanograss photoanode grown with PEG surfactant (at 200 °C) has shown the highest photocurrent of 2.2 mA/cm2 at RHE 1.23VRHE and photoconversion efficiency of 1.4% at 0.46 VRHE. The longer nanograss has shown lower charge transfer resistance and higher charge carrier concentration, which is favorable for enhancing the PEC performance.

Optimal Dispersion of Antimony-Doped Tin Oxide (ATO NPs) in Different NMP Solvent Ratios for Maximizing Photovoltaic Efficiency of Carbon-Based Perovskite Solar Cells

This study addresses interface defects in tin oxide (SnO₂) electron transport layers (ETLs) for perovskite solar cells (PSCs) by doping SnO₂ with antimony (12.9% Sb/Sn). Using a diffusion-precipitation method with varying ratios of N-Methyl-2-Pyrrolidone (NMP) and distilled water (DW) as solvents, antimony-doped tin oxide (ATO) nanoparticle layers were formed and deposited on FTO substrates. Structural and compositional analyses (XPS, EDX, and XRD) confirmed successful Sb incorporation, maintaining the SnO₂ lattice with reduced particle size. Higher NMP ratios improved conductivity to 12 S/cm, enhanced charge transport, and raised the bandgap from 3.67 eV to 3.84 eV. Optimal 100% NMP conditions yielded ATO-based ETLs achieving a power conversion efficiency (PCE) of 23.645%, with a fill factor (FF) of 43.681%, open-circuit voltage (VOC) of 1.202 V, and short-circuit current density (JSC) of 23.87 mA/cm2, underscoring the potential of ATO layers for high-performance PSCs.

Exploring the potential of CdSe nanostructured thin films for energy conversion and environmental remediation

Abstract The rapid thermal evaporation method was employed to prepare cadmium selenide (CdSe) nanostructured thin films with varying thicknesses on glass and FTO substrates. The films were characterized for their structural, optical, and electrochemical properties. Scanning electron microscope (SEM) analysis revealed inhomogeneous surfaces with particle sizes ranging from 18 to 46 nm. The photocatalytic performance of the CdSe films was evaluated by the degradation of methylene blue (MB) dye under visible light, with varying pH values, achieving a degradation efficiency of 100 % at pH 10 after 180 minutes. Photocurrent density measurements demonstrated the films' ability to sense visible light. We performed a cyclic voltammetry (CV) measurement and analyzed the CV curves of the CdSe nanostructured thin film electrodes. It clearly shows that the CV curves had a rectangular shape, which suggests that EDLC behavior was present and non-faradaic capacitance was the main type. The photoconversion efficiency measured is 1.4858 at a bias voltage of 0.66 V under illuminated conditions. Nonlinear optical properties were conducted for CdSe nanostructured thin films.

Electrodeposited NiB Films as Bifunctional Electrocatalysts in Alkaline Water Electrolizer

Abstract Sustainable electrochemical energy generation requires cost-effective, noble-metal-free electrocatalysts for hydrogen and oxygen production in electrolyzers. This study used electrodeposition to create crystalline NiB films with different boron (B) contents—Ni-B(1.17 wt.%), Ni-B(1.06 wt.%), Ni-B(0.94 wt.%), and Ni-B(0.89 wt.%)—on FTO substrates. These films were tested as bifunctional electrocatalyst electrodes for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in alkaline media. The NiB films' composition and morphology were analyzed using SEM, AFM, XRD, GD-OES, and XPS. Linear sweep voltammetry assessed their electrocatalytic performance. Higher B content in the films promoted the formation of electroactive NiOOH, enhancing the OER. The Ni-B(1.17 wt.%) electrode required an overpotential of 380 mV to reach 10 mA cm⁻² for OER, while the Ni-B(1.06 wt.%) electrode required 146 mV for the same current density for HER. An alkaline water electrolyzer using Ni-B(1.17 wt.%) as the anode and Ni-B(1.06 wt.%) as the cathode achieved a current density of 10 mA cm⁻² at 1.71 V for overall water splitting. The system showed stability over 12 hours of testing. The results indicate that NiB films on FTO substrates are promising, low-cost bifunctional electrocatalysts for alkaline water electrolysis, offering an alternative to noble-metal-based electrocatalysts.

Preparation and Performance of Ce-Doped V2O5 Thin Films Deposited on FTO Substrates

Preparation and Performance of Ce-Doped V2O5 Thin Films Deposited on FTO Substrates

Low-cost fabrication methods of ZnO nanorods and their physical and photoelectrochemical properties for optoelectronic applications

Zinc Oxide (ZnO) nanorods have great potential in several applications including gas sensors, light-emitting diodes, and solar cells because of their unique properties. Here, three low cost and ecofriendly techniques were used to produce ZnO nanorods on FTO substrates: hydrothermal, chemical bath deposition (CBD), and electrochemical deposition (ECD). This study explores the impact of such methods on the optical, structural, electrical, morphological, and photoelectrochemical properties of nanorods using various measurements. XRD analysis confirmed the hexagonal wurtzite structure of ZnO nanorods in all three methods, with hydrothermal showing a preferred orientation (002) and CBD and ECD samples showing multiple growth directions, with average particle sizes of 31 nm, 34 nm, and 33 nm, respectively. Raman spectra revealed hexagonal Wurtzite structure of ZnO, with hydrothermal method exhibiting higher E2 (high) peak at 438 cm−1 than CBD and ECD methods. SEM results revealed hexagonal ZnO nanorods became more regular and thicker for the hydrothermal method, while CBD and ECD led to less uniform with voids. UV-vis spectra showed absorption lines between 390 nm and 360 nm. Optical bandgap energies were calculated as 3.32 eV, 3.22 eV, and 3.23 eV for hydrothermal, CBD, and ECD samples, respectively. PL spectra revealed UV emission band with a small intensity peak around 389 nm and visible emission peaks at 580 nm. Temperature dependent PL measurements for ZnO nanorods indicated that the intensities ratio between bound exciton and free exciton decreases with temperature increases for the three methods. Photocurrent measurements revealed ZnO nanorod films as n-type semiconductors, with photocurrent values of 2.25 µA, 0.28 µA, and 0.3 µA for hydrothermal, CBD, and ECD samples, and photosensitivity values of 8.01, 2.79, and 3.56 respectively. Our results suggest that the hydrothermal method is the most effective approach for fabricating high-quality ZnO nanorods for optoelectronic applications.

Revolutionizing dye-sensitized solar cells: Chassalia curviflora fruit extract as photosensitizer and charge recombination inhibitor

The utilization of natural dyes from Chassalia curviflora (CCE), which were successfully extracted to provide bioactive chemicals for the development of dye-sensitized solar cells (DSSCs), is the main focus of this work. These CCEs efficiently absorb light and stop charge recombination in solar cells after being extracted using ethanol. The absorption properties of these natural dyes are discovered to be greatly influenced by the kind and concentration of CCE, with an absorption peak observed at 350 nm. The dyes’ improved adsorption properties on TiO2 are indicated by the presence of functional groups, bond stretching, and bending features, as confirmed by FTIR and UV–Visible spectroscopic investigations. In the DSSC design, these dyes have been effectively combined with an FTO substrate covered with TiO2, serving as a photoanode. The resultant solar cells, which comprise a graphite-based counter electrode, I−/I3− electrolyte, and photoanode, have a power conversion efficiency (PCE) of 0.49 %. The measurements for fill factor, Voc, and Jsc are 0.4761, 1.652 mA/cm2, and 0.52 V, in that order. The phytochemical components of the dye are shown to be crucial in trapping electrons and holes, hence reducing charge recombination and promoting enhanced charge transport towards the titanium dioxide transmission group finding is noteworthy. Furthermore, a dipping time analysis reveals that a 15-minute duration is optimal for achieving a 0.146 % photoelectric conversion efficiency in DSSCs utilizing CCE.

Optimizing sensitizer concentration from senna tora leaves for enhanced interfacial interactions in dye-sensitized solar cells

A novel approach is adopted for the determination of the optimum concentration of natural dye powder extracted from the leaves of Senna Tora in the solvent ethanol and soak the TiO2 coated FTO substrate to be used as photoanode of dye sensitized solar cell (DSSC). Various concentration (0.5 g/15 ml, 0.75 g/15 ml, 1 g/15 ml and 1.5 g/15 ml) of the dye powder in ethanol is subjected for UV–Visible, FTIR and PL Spectroscopic studies. Solar cells are fabricated with the sensitizer in Photoanode, I-/I3- electrolyte and counter electrode of graphite coated FTO are subjected for JV characterization to determine the best concentration of dye to give good photoconversion efficiency. From the study, it is found that, among the four concentrations of the dye in ethanol for the extraction of the dye, 1.5 g in 15 ml of ethanol has shown higher efficiency of 2.29 % with fill factor, short circuit current density and open circuit voltage of 0.84, 2.64 mA/cm2 and 1.03 V.

Pseudocapacitive Na ion storage in binder-less, carbon additive-free Nb2O5-x electrode synthesised via solvothermal-assisted electro-coating with enhanced areal capacitance and lowered impedance parameters

Negatrodes with wide negative operating voltage, high electrochemical storage capacity, and intrinsic metal ion intercalation abilities are vital to the continuous development of storage devices with simultaneous energy and power density improvement. Herein, we report binder-less coating of non-stoichiometric vacancy-implanted Nb2O5-x as carbon additive-free negatrode on FTO substrate for asymmetric supercapacitor and sodium ion capacitor applications. The negatrode was fabricated through vacuum-less and low-temperature solvothermal-assisted electro-coating technique and yielded several orders of enhancement in its areal capacitance and retained ca. 90 % of its capacity after 5000 cycles of charge-discharge in aqueous Na+ electrolyte. The solvothermal treated electro-coated electrode (STT_Nb2O5-x) achieved an areal capacitance of 22.58 mF/cm2, which was far higher than those of hydrothermal-treated electro-coated HTT_Nb2O5 and Nb2O5 electrodes. The solvothermal treatment simultaneously enhanced the electro-coated samples' impedance properties and mass load through oxygen vacancy implantation and re-crystallization of the electro-coated Nb2O5 layer, respectively. This study presented a facile and energy-efficient technique of direct coating of defect-enhanced pseudocapacitive nanomaterials for the fabrication of electrochemical storage devices.

Comparative studies on pinhole free CBD-CdZnS thin films on ITO and FTO substrate

The development of CdZnS thin films using the chemical bath deposition process in nonaqueous media is a technological challenge. In this work, 75 millilitres of ethylene glycol and ethanol (1:2 ratios) were used to develop a CdZnS thin film on ITO and FTO glass substrates using cadmium acetate, zinc sulphate, and thiourea. The ideal bath temperature was kept at 1300C and the anneal temperature of the film that had been deposited in the air was maintained at 3500C. The films have been examined using FTIR, WCA, FESEM, and XRD. XRD studies reveal that CdZnS films have a hexagonal crystal structure with a preference for orientation (002) during the deposition and annealing processes and the assessment of the various attributes have been done, such as dislocation density, micro strain, and grain size. FESEM study indicates that as deposited film on ITO glass have smooth surface and grains appear in the form of small needle shape of equal sizes where as FTO substrate reveals the grains of equal size throughout the entire surface in cluster form. It is also confirmed that both the CdZnS films formed on ITO and FTO substrates have hydrophilic quality. The presence of chemical bonds and functional groups was confirmed by FTIR analysis.

Oxygen desorption enabled visible light sensing in embossed TiO2 nanogratings fabricated via thermal nanoimprinting

In this work, the fabrication of the nanoimprinted titanium dioxide (TiO2) gratings via thermal nanoimprinting lithography method (T-NIL) and its visible light response are studied. A polydimethylsiloxane (PDMS) primary mould, which in turn made via pattern transfer of micro/nano tracks present in the optical discs is used in T-NIL process. A transparent TiO2 film on a FTO substrate was subjected to pattern transfer from the PDMS mould. The imprinted TiO2 was post annealed to obtain anatase phase. The optical properties and photo response behaviour of plain and nanoimprinted TiO2 films were measured and compared. Raman spectroscopy measurements indicated the surface enhanced Raman scattering in imprinted samples. The imprinted TiO2 showed reduced reflectance compared to plain TiO2 films due to the increased light path length because of multiple reflections leading to in coupling of light. Photo response was observed under visible light illumination conditions, wherein imprinted TiO2 films showed appreciable photocurrent, which is otherwise very minimal in plain TiO2. The visible light photosensing in imprinted TiO2 occur due to the oxygen adsorption-desorption during the post deposition annealing and under illumination respectively. This work makes use of low-cost PDMS primary mould and T-NIL at favourable temperature and pressure conditions with a promising outlook for fabricating imprinted TiO2 with photo sensing ability and adaptability for large area upscaling.

Fabrication of WO3/Co3O4 nanorods as a p-n heterojunction photoanode for efficient photoelectrochemical oxygen evolution

Developing efficient photoelectrocatalysts is seen as a promising method for generating hydrogen through photoelectrochemical (PEC) water splitting. In this study, the WO3/Co3O4 heterojunction was fabricated on FTO substrates, serving as an effective photoanode for PEC water splitting. The p-type Co3O4 nanoparticles were loaded onto n-type WO₃ nanorods to create a p-n heterojunction, thereby reducing charge recombination due to the internal electric field at the heterointerface. Under LED illumination (∼80 mW/cm2), the photocurrent density of the WO3/Co3O4 photoanode reached 161.1 μA/cm2 at 1.23 V vs. RHE, which is 2.3 times higher than that of bare WO3 photoanode. The results show that loading Co3O4 onto WO3 nanorods significantly increased the absorption of visible light, boosted charge carrier density, and enhanced surface reaction kinetics. This work indicates the construction of p-n heterojunction photoanodes for achieving effective photoelectrochemical performance.

Variable valence I3−/I− ionic bridge assisting CuI nanoparticle/BiOI nanosheet S-scheme photocatalyst with hydrophobic surface for boosting CO2 conversion with 100 % CO selectivity

The photocatalyst film, composed of tetragonal BiOI nanosheets and cubic phase CuI nanoparticles, was synthesized on the FTO substrate by a simple electro-deposition method. The orderly crisscrossed nanosheet structure caused exterior hydrophobic property, resisting the excess H2O molecules and further inhibiting the competitive H2O reduction process. The novel BiOI/CuI catalyst exhibited excellent photocatalytic ability of CO2 reduction into CO with 100 % selectivity in H2O vapor. Typically, the optimal 150BiOI/CuI photocatalyst exhibited CO yield of 7237.65 μmol/cm2 after 11 h of simulated sunlight illumination, achieving quantum efficiency of 2.5 % at 380 nm. The excellent performance of the BiOI/CuI composite film in photocatalytic CO2 reduction can be attributed to the construction of hydrophobic surface and S-scheme heterojunction with I3−/I− redox mediator, as confirmed by the in-situ XPS, hole injection test and cyclic voltammetry results. This study lays the groundwork for employing highly efficient iodide-based photocatalysts in gas-liquid-solid triphase catalytic systems.

Development of photovoltaic and photodetection characteristics in CdS/P3HT devices through Al-doping

CdS thin films were deposited by chemical bath deposition onto FTO substrates with Al concentrations of 0, 1, 3, 5 and 6 %. X-ray diffraction revealed introduction of 1 % Al-doping reduced dislocation density and enhanced the crystal quality of CdS. Scanning electron microscopy confirmed a reduction in grain size in Al-doped CdS films compared to CdS. N3 and P3HT layers were spin-coated onto the prepared substrates, respectively. The fabrication of the solar cells was completed using Ag silver paste for the top contact. The lowest photoluminescence peak intensity was achieved for CdS (3 %Al):P3HT solar cell, indicating efficient exciton dissociation. 3 % Al-doped CdS-based device exhibited the highest efficiency at 0.210 %, nearly seven times that of reference device. CdS (3 %Al):P3HT device demonstrated the best photodetection characteristics, with a responsivity of 2.2 × 10-2 A/W, detectivity of 3.3 × 108 Jones, response time of 13 ms, and recovery time of 12 ms at zero bias voltage.

Preparation of Oriented Nanoporous Magnetite Films by a Template-Free Solution Process from Iron Oxyhydroxide Films

Nanoporous oxide films composed of nanocrystal assemblies with an aligned crystallographic orientation are key nanostructures for efficient interfacial reactions. However, a simple, template-free method for their formation remains a challenge. Layered metal hydroxide (LMH) films are a promising precursor for spontaneous formation of nanoporous oxide films.[1-4] LMHs have a layered structure comprising 2D sheets of edge-shared octahedral hydroxide, i.e., brucite structure, with or without interlayer anions and water molecules. Calcination of LMH results in dehydration, anion elimination, and volume shrinkage, leading to the spontaneous formation of nanoporous oxides.In this study, we have prepared nanoporous and ferrimagnetic magnetite (Fe3O4) films by using layered iron hydroxides, namely, green rust (GR), as a precursor. Generally, GR has a brucite-type structure containing Fe2+ and Fe3+ ions, and is highly susceptible to oxidation by oxygen in water and air, leading to the formation of iron oxyhydroxides (FeOOH). Here, GR films were electrochemically deposited on FTO substrates in an aqueous solution containing Fe2+ and NO3 − ions at room temperature. Drying the GR films in air resulted in the formation of two-type FeOOH films, depending on the electrodeposition condition. Characterization using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and FT-IR spectroscopy revealed that one is [010]-oriented γ-FeOOH films, and the other is [001]-oriented δ-FeOOH films. The obtained FeOOH films had a mille-feuille like morphology with 500–700 nm thickness. Heat treatment of these two-type FeOOH films under vacuum at 500 °C resulted in the formation of [110]- and [111]-oriented nanoporous Fe3O4 films. The obtained Fe3O4 films showed a ferrimagnetic behavior in VSM measurements and had a nanoporous structure comprising nanoparticles with 50–100 nm diameter.Finally, a possilble interpretation for the observed orientation relationships between the FeOOH and Fe3O4 was also discussed on the basis of pyrolysis intermediates of FeOOH and similarity in their atomic arrangements. References T. Shinagawa, M. Watanabe, T. Mori, J.-i. Tani, M. Chigane and M. Izaki, Inorg. Chem., 57, 13137 (2018).T. Shinagawa, M. Chigane and M. Izaki, ACS Omega, 6, 2312 (2021).T. Shinagawa, M. Chigane and M. Takahashi, Cryst. Growth Des., 22, 4122 (2022).T. Shinagawa, N. Kotobuki and A. Ohtaka, Nanoscale Adv., 5, 96 (2023). Figure 1

Peculiar photoelectrochemical activity of zinc oxide and tin dioxide

Zinc oxide thin films made by pulsed reactive magnetron sputtering combined with RF ECWR plasma on FTO or ITO substrates exhibit high photoelectrochemical activity for water splitting under UV light, but are unstable against photocorrosion. It can be suppressed by a protective layer of SnO2 made by atomic layer deposition. The SnO2 layer is quasi-amorphous in the as-received state, but the thermal treatment causes partial crystallization to cassiterite, without significant change of the optical band gap. Ferrocene in acetonitrile electrolyte solution is a useful redox probe for the blocking-quality tests of thin films of n-semiconductors. Both ZnO and SnO2 are sensitive to irreversible electrochemical doping at potentials negative to the flatband potential. The flipping of electrochemical work functions of the Zn-terminated (0001) and O-terminated (000–1) faces of ZnO (wurtzite) takes place in acetonitrile vs. aqueous electrolyte solutions. The potentials for photocurrent onset are near the flatband potentials in an aqueous electrolyte solution for both ZnO and SnO2.

(Invited) Efficient P-Doping Via Suppressing Bad P−Sn Interaction

The utilization of non-metallic phosphorus (P) doping is recognized for its advantages in enhancing the conductivity of hematite while minimizing recombination. This is attributed to the suppression of electron trapping facilitated by the favorable electron state of P5+. However, our investigation reveals a significant impact on the overall photoelectrochemical (PEC) performance of P-doped Fe2O3 due to tin (Sn) diffusion from the bottom FTO substrate. Upon identifying the unfavorable interaction between the unintentional dopant Sn4+ and intentional dopant P5+, we have developed a straightforward P-doping method. The resulting P:Sn:Ti-Fe2O3 (P:Sn:Ti triple-doped Fe2O3) exhibits a remarkable improvement in photocurrent density, reaching 3.44 mA cm−2 at 1.23 VRHE, surpassing values reported in previous P-doping hematite studies. Following co-catalyst deposition, the NiFeOx/P:Sn:Ti-Fe2O3 photoanode achieves a maximum photocurrent density of 4.30 mA cm−2 at 1.23 VRHE. This study affirms that suppressing the negative interaction between dopants is crucial for significantly enhancing PEC performance.

Silver nanogranules-decorated ZnO hybrid nanostructures with enhanced UV photoresponses

Detecting low-power ultraviolet (UV) light is crucial for practical applications. However, 1D ZnO/Ag based photodetectors (PDs) suffer from high expenses and care due to special operating conditions, posing challenges in capturing weak light signals and response time. To overcome these limitations, we integrate ZnO nanostructures with localized surface plasmon resonance of Ag nanoparticles via a surfactant-free hydrothermal-assisted polyol method, resulting in a notable bandgap reduction. SEM analysis revealed roughly spherical nanostructures for pristine ZnO and a porous structure in ZnO@Ag, around 1.4 µm in size with small agglomerates. XRD patterns showed reduced ZnO diffraction peak intensities in ZnO@Ag, confirming their core-like ZnO morphology. The fabricated ZnO@Ag heterojunction PD on an FTO substrate resulted in notable enhancement of PD performance. The ZnO@Ag heterojunction PD demonstrated a rapid 1.77 s response time, a 0.64 s recovery time and a specific detectivity of 11×107 cmHz1/2W−1, indicating its potential for low-cost and sustainable optoelectronics.

Inorganic CsPbI2Br as Potential Absorber Layer for Perovskite Solar Cells: Theoretical and Experimental Study

AbstractHerein, we reported the numerical simulation studies of the metal halide perovskite solar cells (MHPSCs) using solar cell capacitance one‐dimensional (SCAPS‐1D). CsPbI2Br perovskite has been adopted as the absorber layer and thickness of the absorber layer has been optimized to improve the performance of the simulated MHPSCs. Various electron transport layers (ETLs) and hole transport layers (HTLs) were explored for the optimization of high performance MHPSCs. The simulation studies demonstrated excellent efficiency of 20.22 % for the optimized device structure of FTO/SnO2/CsPbI2Br/PTAA/Au using SCAPS‐1D. The experimental study was also conducted to explore the potential of the simulation investigations. The MHPSCs device (FTO/SnO2/CsPbI2Br/PTAA/Au device) was fabricated under controlled humidity (40 %). The CsPbI2Br layer was grown on FTO substrate and its phase purity, crystallinity, surface morphological, and optical properties were determined by using X‐ray diffraction, and ultraviolet‐visible absorption spectroscopy. The fabricated MHPSCs showed decent efficiency of 14.4 %.

Concentrations Influence of Complexing Agents on the Physicochemical Properties of Chemical Bath Deposited n‐Type FeSxOy for Homostructure Solar Cell

A chemical bath deposition (CBD) is applied to deposit n‐type iron sulfide (FeSxOy) film on fluorine (F)‐doped tin oxide (SnO2)–FTO substrate. The duration, temperature, and magnetic stirrer's speed in CBD are 3 h, 75 °C, and 100 revolutions per minute. The influence of complexing agents’ concentration (≤200 mm)–acid (tartaric and lactic) on the physicochemical properties of film is studied. All films are n‐type semiconductors with large bandgap (2.95–3.58 eV) and contain high oxygen (≈56–83%). Scanning electron microscopy image shows the 50 mm tartaric acid film has a uniform and denser surface morphology. FeSxOy film with tartaric acid has lesser goethite and hematite peaks in X‐ray diffraction than lactic acid. The FeSxOy film with 100 mm lactic acid exhibits a slightly higher transmittance at ≈350–450 nm. The FeSxOy homostructure reveals average open‐circuit voltage (Voc) = 0.45 V, short‐circuit current (Jsc) = 0.0003 mA cm−2, fill factor =38%, and efficiency (η) = 0.57%.