Rapid microwave synthesis of Cu2ZnSnS4 nanocrystals for photovoltaic junctions

Copper zinc tin sulfide ( CZTS) nanocrystal (NC) ink was prepared using thiourea as sulphur source by microwave assisted process. Thin films fabricated by doctor blading technique were then used to analyze the structure and morphology of the CZTS NCs. Variation in the properties of the NCs with varying Zn content in the precursor solution was studied. A Zn/Sn ratio of 1.4 with a Cu/(Sn + Zn) ratio of 0.8 in the starting solution was identified as an optimum compositional ratio to get good optoelectronic properties. Synthesis of CZTS NCs was done in ethylene glycol solvent and in a solvent which is a 1:1 mixture of isopropanol and poly ethylene glycol. The films developed from the latter ink showed better morphological and optoelectronic properties. CZTS thin films show absorption coefficient of the order of 10⁴ cm^?1 and optical band gap of 1.5 eV. The electrical resistivity was found to be 2.5 × 10² Ω/cm and hole mobility 0.051 cm²/ (Vs). Glass/FTO/CdS/CZTS multilayer structures were fabricated to form P‐N junctions. A knee voltage of 0.8 V from the I‐V characteristics of the PN junction indicates that a good V_oc can be expected from a solar cell constructed with CZTS ink as absorber layer.     

Growth of n- and p-type ZnTe semiconductors by intrinsic doping

Using intrinsic doping, n- and p-type ZnTe thin films have been electrodeposited (ED) on glass/fluorine-doped tin oxide (FTO) conducting substrate in aqueous solutions of ZnSO₄·7H₂O and TeO₂. The intrinsic doping was achieved by simply varying the deposition potential. The films have been characterised for their structural, optical, electrical, morphological and compositional properties using X-ray diffraction (XRD), optical absorption, photoelectrochemical (PEC) cell measurements, scanning electron microscopy and energy-dispersive X-ray analysis techniques, respectively. The XRD results reveal that the electroplated films are polycrystalline and have hexagonal crystal structures. Optical absorption measurements have been used for the bandgap determination of as-deposited and heat-treated ZnTe layers. The bandgap of the as-deposited ZnTe films are in the range (1.70–2.60) eV depending on the deposition potential. PEC cell measurements reveal that the ED-ZnTe films have both n- and p-type electrical conductivity. Using the n- and p-type ZnTe layers, a p-n homo-junction diode with device structure of glass/FTO/n-ZnTe/p-ZnTe/Au was fabricated. The fabricated diode showed rectification factor of 10², ideality factor of 2.58 and threshold voltage of ~0.25 V.     

Cigs flexible nano solar cell by inert argon gas condensation

The Cu(In_0.7Ga_0.3)Se₂ nano solar cell pn junction structure consist of six layers of Al/CIGS/nano-CIGS/CdS/ITO/PET with thicknesses about 200, 500, 70, 100, 150 nm and 170 um were deposited by thermal evaporation technique at vacuum pressure 2 × 10^–5 mbar respectively. where the ITO/PET conductive flexible substrate with sheet resistance 15 Ohms per sq. The X-ray diffraction analysis showed that as-deposited thin films CIGS and CdS are polycrystalline where optical energy gap and carrier concentration are found that 1.15 and 2.38 eV with p = 3.58 × 10¹⁰ cm^–3 and n = 3.11 × 10¹³ cm^–3 respectively. CIGS nano solar cell thin films are deposited on CdS/ITO/PET with assistance of inlet Argon gas vacuum pressure at 1, 5, 20 mbar by thermal evaporation technique at room temperature by using Inert gas condensation (IGC) is the method by which one can deposit films with high purity as deposition is done in low vacuum. The high magnification SEM image of CIGS nano-structures synthesized at 20 mbar revealed that the particles have exact spherical shape with sizes ranged from few nanometers to hundreds nanometers due to agglomeration effect. It was found that the grain size and the root mean square of surface roughness increases as Argon gas pressure increase. Therefore the structure of CIGS thin films has been changed from polycrystalline to nanostructure and have been found with increase Argon gas vacuum pressure from 1mbar to 5 mbar and then 20 mbar will increase grain size at 2θ = 32° from 15.9, 18.9 and 25.7 nm with decrease optical energy gap from 1.54, 1.44 and 1.26 eV respectively. The results showed the efficiency increase from 1.37% of CIGS/CdS to 2.01% of CIGS nano thin films of solar cells.     

Substrate temperature effect on transparent heat reflecting nanocrystalline ITO films prepared by electron beam evaporation

In this study, indium tin oxide (ITO) thin films were preparedon glass substrate by electron beam evaporation technique and then were annealed in air atmosphere at 350 °C for 30 min. Increasing substrate temperature (T_s) from 25 to 380°°C reduced sheet resistance of ITO thin films from 150(Ω/□) to 14(Ω/□). The UV-visible-near IR transmittance and reflectance spectra were also confirmed that the substrate temperature has significant effect on the properties of heat reflecting thin films. High transparency (83%) over the visible wavelength region of spectrum and (over 90%) reflectance in near-IR region were obtained at T_s = 300° C. Plasma wavelength, carrier concentrations (n_e) and refractive index of the layer were also calculated. The allowed direct band gap at the temperature range 100–300° C was estimated to be in the range 3.71–3.89 eV. Band gap widening due to increase in substrate temperature was observed and is explained on the basis of Burstein-Moss shift. XRD patterns showed that the films were polycrystalline. High quality crystalline thin films with grain size of about 40 nm were obtained.     

Surface microstructure and performance of TiN monolayer film on titanium bipolar plate for PEMFC

The influence of bias voltage on surface microstructure of TiN films deposited on Ti substrate by multi-arc ion plating was systematically investigated. The TiN films were characterized using X-ray diffraction, scanning electron microscopy and atomic force microscopy. The corrosion resistance was tested by potentiodynamic polarization and electrochemical impedance spectroscopy at 70–80 °C in the simulated PEMFC cathode environment. The results show that the surface microstructure of TiN film depends strongly on the bias voltages. At the bias voltage of −100 V, TiN film shows the optimum surface microstructure with the lowest surface roughness R_z of 0.039 μm tested by AFM and relatively high compactness. The optimized TiN film exhibits excellent corrosion resistance with corrosion current density of 0.87 μA/cm² in a 0.5 M H₂SO₄ + 2 ppm HF solution at 80 °C with air and a low interfacial contact resistance (ICR) value of 3.0 mΩ cm² at a compaction force of 140 N/cm². These results support TiN as a promising coating material for Ti bipolar plates.     

Partially reduced Ni0.8Co0.15Al0.05LiO2-δ for low-temperature SOFC cathode

Nowadays, Ni_0.8Co_0.15Al_0.05LiO_2-δ (NCAL) has been increasingly applied into the solid oxide fuel cell (SOFC) field as a promising electrode material. Here, the performances of NCAL cathode were investigated for low-temperature SOFCs (LT-SOFCs) on Ce_0.8Sm_0.2O_2-δ (SDC) electrolyte. After on-line reduction of NCAL for 30 min, the partially reduced NCAL, i.e., NCAL(r), was employed as the new cathode and its performances were also investigated. The area specific resistances of NCAL and NCAL(r) cathodes on SDC electrolyte are 7.076 and 1.214 Ω cm² at 550 °C, respectively. Moreover, NCAL(r) exhibits the activation energy of 0.46 eV for oxygen reduction reaction (ORR), which is much lower than that of NCAL (0.88 eV). The fuel cell consisted of NCAL electrodes and SDC electrolyte shows an open circuit voltage (OCV) of 0.95 V and power output of 436 mW cm^?2 at 550 °C. After cathode on-line optimization, the cell's OCV and power output are significantly increased to 1.01 V and 648 mW cm^?2, which mainly attributed to the accelerated ORR and decreased electrode polarization resistance. These results demonstrate that NCAL(r) is a promising cathode material for LT-SOFCs.     

Effects of step-deposition on structures and properties of transparent conducting aluminum-doped zinc oxide films prepared by DC magnetron sputtering

The 2 wt% aluminum-doped zinc oxide films (AZO) was sputtered on corning glass plate at temperatures of 30–200 °C by DC magnetron sputtering using ceramic target. The microstructures and electrical resistivity of thin films were investigated by scanning electron microscope (SEM) and the van der Pauw method. The optical transmittances of films were measured by UV visible spectrophotometer in the wavelength of 300–900 nm. It was found that the average optical transmittances of specimens were 88%. Highly oriented AZO films in the (0 0 2) direction was observed in specimens as increasing of the substrate temperature. The dense film increased as the temperature increases. In addition, craters of greater depth with more compactness were obtained by step-deposition. The lowest resistivity of 9×10⁻⁴ Ω cm with film thickness of 700 nm was found in specimen grown by step-deposition at 200 °C.     

Chemically grown Bi2S3 nanorod films for hydrogen evolution

Bi₂S₃ nanorod films were grown on ITO-coated glass substrates through chemical bath deposition (CBD) and annealing in a sulfur atmosphere. The as-deposited films were amorphous/nanocrystalline, with a particle size of 20 nm and a direct optical band gap of 1.87 eV. Upon annealing at 350 °C, the films exhibited a nanorod morphology with a length of 300 nm. Further increasing the temperature from 400 to 450 °C resulted in an increased diameter of nanorods. The direct optical band gap decreased from 1.68 to 1.47 eV upon increasing the annealing temperature from 350 to 400 °C. Photoelectrochemical (PEC) measurements showed that the nanorod films grown on ITO-coated glass substrates exhibited significantly increased PEC activity owing to their nanorod structures. The Bi₂S₃ nanorod films formed at 400 °C exhibited a maximum photocurrent density of 6.1 mA/cm² at 1 V, which was 2.5 times higher than that of the as-deposited films. The enhancement in the photocurrent density could be due to the effective visible-light absorption of Bi₂S₃ nanorods as a result of the increased crystallinity and decreased band gap. This study demonstrates the synthesis route involving a simple and inexpensive CBD method of Bi₂S₃ nanorod films for the optimized PEC water-splitting applications.     

A novel Al and Y codoped ZnO/n-Si heterojunction solar cells fabricated by pulsed laser deposition

Al and Y codoped ZnO (AZOY) transparent conducting oxide (TCO) thin films were first deposited on n-Si substrates by pulsed laser deposition (PLD) to form AZOY/n-Si heterojunction solar cells. However, the properties of the AZOY emitter layers are critical to the performance of AZOY/n-Si heterojunction solar cells. To estimate the properties of AZOY thin films, films deposited on glass substrates with various substrate temperatures (T_s) were analyzed. Based on the experimental results, optimal electrical properties (resistivity of 2.8 ± 0.14 × 10^?4 Ω cm, carrier mobility of 27.5 ± 0.55 cm²/Vs, and carrier concentration of 8.0 ± 0.24 × 10²⁰ cm^?3) of the AZOY thin films can be achieved at a T_s of 400 °C, and a high optical transmittance of AZOY is estimated to be >80% (with glass substrate) in the visible region under the same T_s. For the AZOY/n-Si heterojunction solar cells, the AZOY thin films acted not only as an emitter layer material, but also as an anti-reflected coating thin film. Thus, a notably high short-circuit current density (J_sc) of 31.51 ± 0.186 mA/cm² was achieved for the AZOY/n-Si heterojunction solar cells. Under an AM1.5 illumination condition, the conversion efficiency of the cells is estimated at only approximately 4% (a very low open-circuit voltage (V_oc) of 0.24 ± 0.001 V and a fill factor (FF) of 0.51 ± 0.011) without any optimization of the device structure.     

Enhanced activity of Pd/α-MnO2 for electrocatalytic oxygen evolution reaction

This work describes the application of α-MnO₂ and Pd/α-MnO₂ as electrocatalysts in the oxygen evolution reaction (OER). Characterization data revealed that the Pd²⁺ precursor has been oxidized during the synthesis, and the resulting Pd⁴⁺ ions have unprecedently replaced the lattice framework Mn³⁺ ions of α-MnO₂. Furthermore, formation of PdO nanoparticles was also observed. Lower OER overpotential at j = 10 mA cm^?2 (636 mV) was obtained for Pd/α-MnO₂ in relation to α-MnO₂ (700 mV), what is in alignment with the lower charge transfer resistance of Pd/α-MnO₂ (4.9 kΩ cm²) compared to α-MnO₂ (10.4 kΩ cm²). Lower Tafel slope (73 mV dec^?1) and higher TOF (2.87 × 10^?4 s^?1) at overpotential of 350 mV was obtained for Pd/α-MnO₂ in relation to α-MnO₂ (Tafel of 77 mV dec^?1 and TOF of 1.94 × 10^?4 s^?1), indicating a faster electron transfer kinetics promoted by Pd. Pd/α-MnO₂ was stable at j = 14 mA cm^?2 for 6 h.     

Thin film silicon solar cells by AIC on foreign substrates

This paper presents the fabrication of thin film crystalline silicon solar cells on foreign substrates like alumina, glass–ceramic (GC) and metallic foils (ferritic steel—FS) using seed layer approach, which employs aluminium induced crystallisation (AIC) of amorphous silicon. Effect of hydrogen content in a-Si:H precursor films on the AIC process has been studied and the results showed that defects in the AIC grown films increased with increase of hydrogen content. At the optimal thermal annealing conditions, the AIC grown poly-Si films showed an average grain size of 7.6, 26, and 8.1 μm for the films synthesised on alumina, GC, and FS, respectively. The grains were (1 0 0) oriented with a sharp Raman peak around 520 cm^?1. Similarly, n-type seed layers were also fabricated by over-doping of as-grown AIC layers using a highly phosphorus doped glass solution. The resistivity of as-grown films reduced from 8.4×10^?2 Ω cm (p-type) to 4.1×10^?4 Ω cm (n-type) after phosphorus diffusion. These seed layers of n-type/p-type were thickened to form an absorber layer by vapour phase epitaxy or solid phase epitaxy. The passivation step was applied before the heterojunction formation, while it was after in the case of homojunction. Open circuit voltage of the junctions showed a strong dependence on the hydrogenation temperature and microwave (μW) power of electron cyclotron resonance (ECR) plasma of hydrogen. Effective passivation was achieved at a μW power of 650 W and hydrogenation temperature of 400 °C. Higher values of solar conversion efficiencies of 5% and 2.9% were achieved for the n-type and p-type heterojunction cells, respectively fabricated on alumina substrates. The analysis of the results and limiting factors are discussed in detail.     

Electrodeposited tin selenide thin films for photovoltaic applications

Tin selenide thin films of about 300 nm thickness were electrodeposited on SnO₂:F coated transparent conductive oxide glass substrates. The optimum deposition potential was determined from cyclic voltammetry measurements. The films were polycrystalline with orthorhombic structure and the grain size was about 18 nm. SEM images showed a highly porous film structure. The band gap estimated from optical spectra of these films showed absorption due to direct transition occurring at 1.1 eV. Characteristic vibrational modes of the SnSe were observed in the Raman spectrum. The films are p-type, photosensitive, and the conductivity measured in dark was in the range of 10^?5 Ω^?1 cm^?1. A prototype CdS/SnSe photovoltaic device showed an open circuit voltage of 140 mV and short circuit current density 0.7 mA/cm².     

Enhanced photovoltaic performance of inverted organic solar cells with In-doped ZnO as an electron extraction layer

In the present work, a systematic study has been carried out to understand the effect of In doping on the various properties of the ZnO nanocrystalline thin films. In-doped ZnO nanocrystalline thin films with different indium concentrations (1.98%, 4.03%, 6.74%, 8.62% and 10.48% In) have been synthesized by sol–gel method. The grain size and surface roughness of the In-doped ZnO thin films are observed to be smaller than those of the ZnO thin films. 6.74% In-doped ZnO films with a low resistivity of 1.95 × 10⁻³ Ω cm and a high mobility of 2.19 cm² V⁻¹ S⁻¹ have been prepared under optimal deposition conditions. Inverted organic solar cells containing In-doped ZnO as an electron extraction layer with the structure indium tin oxide (ITO)/In-doped ZnO/poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT): [6,6]-phenyl C₇₁-butyric acid methyl ester (PC₇₁BM)/MoO₃/Al have been fabricated. The inverted organic solar cell with 6.74% In-doped ZnO exhibited a power conversion efficiency of 5.58%, which is the best efficiency reported so far for these type of solar cells. The device performance has been optimized by varying the indium doping concentration. The results clearly demonstrate that significant improvement in power conversion efficiency can be obtained by incorporating In into the ZnO films.     

Enhancing the flash-sinterability of BaZr0.1Ce0.7Y0.2O3-δ proton-conducting electrolyte by nickel oxide doping for possible application in SOFCs

In the present work, effects of nickel oxide doping on flash-sinterability of BaZr_0.1Ce_0.7Y_0.2O_3-δ compound were investigated. A single-phase BZCY7 powder was synthesized by the solid-state reaction route. The effects of using 0.5, 1, 1.5, and 2 wt% of NiO additive on flash sintering of BZCY7 samples were examined. It was revealed that using 0.5 wt% of NiO additive can reduce the onset temperature of flash sintering in all the applied electric fields in the range of 100–500 V/cm and significantly enhances the sinterability of the BZCY7 compound. Microstructural investigations, using field emission scanning electron microscopy and energy-dispersive X-ray mapping, showed that NiO doping can lead to larger grain sizes, while no detectable segregation or second phase was observed. Utilizing electrochemical impedance spectroscopy, the total conductivity of samples at 600 and 700 °C was measured as 4.4 × 10^?3 and 7.0 × 10^?3 S/cm for the undoped BZCY7, and 8.6 × 10^?3 and 1.4 × 10^?2 S/cm for the 0.5 wt% NiO doped BZCY7 sample, respectively. The activation energies of conduction were determined as 0.37 and 0.41 eV for the doped and undoped samples, which represent the presence of predominant and facile protonic conduction.     

Wide-optical bandgap with improved conductivity p-μc-Si:Ox:H films prepared by Cat-CVD

Boron-doped hydrogenated microcrystalline silicon oxide (p-μc-Si:O_x:H) films have been deposited using catalytic chemical vapor deposition (Cat-CVD). The single-coiled tungsten catalyst temperature (T_fil) was varied from 1850 to 2100 °C and films were deposited on glass substrates at the temperatures (T_sub) of 100–300 °C. Different catalyst-to-substrate distances of 3–5 cm and deposition pressures from 0.1 to 0.6 Torr were considered.Optical and electrical characterizations have been made for the deposited samples. The sample transmittance measurement shows an optical-bandgap (Eg_opt) variation from 1.74 to 2.10 eV as a function of the catalyst and substrate temperatures. One of the best window materials was obtained at T_sub=100 °C and T_fil=2050 °C, with Eg_opt=2.10 eV, dark conductivity of 3.0×10^?3 S cm^?1 and 0.3 nm s^?1 deposition rate.     

Enhanced photooxidative desulphurization of dibenzothiophene over fibrous silica tantalum: Influence of metal-disturbance electronic band structure

Fibrous silica tantalum (FSTa) and a series of metal oxides (silver oxide (AgO), copper oxide (CuO) and zinc oxide (ZnO)) supported on FSTa were prepared by hydrothermal and electrochemical method, respectively. X-ray diffraction, nitrogen adsorption-desorption analyses, Fourier-transform infrared, ultraviolet–visible diffuse reflectance spectroscopy, and photoluminescence were used to characterize the catalysts. The catalyst activity towards on photocatalytic oxidative desulfurization (PODS) of 100 mg L^?1 dibenzothiophene (DBT) was ranked in the following order: FSTa (3.03 × 10^?3 mM min^?1) > Zn/FSTa (2.65 × 10^?3 mM min^?1) > Cu/FSTa (2.33 × 10^?3 mM min^?1) > Ag/FSTa (1.46 × 10^?3 mM min^?1) under visible light irradiation for 150 min. This result demonstrated that the addition of metal oxides lowered the efficiency of PODS of DBT, most probably due to the unfit energy level of the photocatalyst towards redox potentials of superoxide anion radical (?O₂^?) and hydroxyl radical (?OH). Nevertheless, among the metal oxides loaded FSTa, Zn/FSTa showed a higher desulfurization rate, which likely due to its higher valence band energy (E_VB = 3.12 eV) than the redox potential of the H₂O/?OH (+2.4 eV vs. NHE), which allowed the production of ·OH for oxidation of DBT into dibenzothiophene sulfone (DBTO₂). In parallel, the hole at the VB of ZnO can also directly oxidize DBT to DBTO_2, as confirmed by the scavenger experiment. A kinetics study using Langmuir–Hinshelwood model illustrated that the photodegradation over Zn/FSTa followed the pseudo-first-order, and adsorption was the rate-limiting step. These findings are believed to aid in the rational design of high-performance photocatalysts for various photocatalytic applications, especially the removal of sulphur-containing compounds from fuel oils.     

Impact of surface oxide on hydrogen permeability of chromium membranes

Hydrogen permeation through pure and oxidised bulk chromium membranes was measured by the classical gas technique to get insight into oxide as a hydrogen permeation barrier (HPB). An additional palladium-coated reference chromium membrane was tested to avoid the influence of native Cr oxide. Key parameters for Cr permeability: P₀ = 3.23 × 10^?7 mol H₂/s/m/Pa^0.5 and E_a = 0.68 eV and Cr diffusivity D₀ = 9.0 × 10^?5 m²/s and E_a = 0.59 eV. In the sample preparation stage, a thin ～2 nm thick oxide was formed. Additional oxidation in pure oxygen at 400 °C increased the thickness from 20 to 50 nm. At this temperature, its efficiency as HPB was evaluated by comparing permeation rates to the reference chromium membrane. The highest permeation reduction factor of ～3900 corresponded to only a ～28 nm thick Cr oxide layer. Surface morphology and oxide thickness were investigated by SEM, while the thickness and type of chromium oxide by XPS.     

Deposition and characterization of earth abundant CuZnS ternary thin films by vacuum spray pyrolysis and fabrication of p-CZS/n-AZO heterojunction solar cells

We report fabrication of solar cell device <ITO/AZO/i-ZnO/CZS/Al> with Copper Zinc Sulfide (CZS) thin films as absorber layer. CZS thin films prepared using chemical spray pyrolysis technique at a pressure of 10⁻³ mbar at different substrate temperatures. Structural, morphological, optical, compositional and electrical properties of as prepared films are investigated. Structural analysis shows crystalline nature with mixed phase containing CuS-ZnS binary composite. Atomic Force Microscopy analysis shows the average particle size of 88 nm. Value of work function obtained from ultraviolet photoelectron spectroscopy is 4.58 eV. The band gap of the as-prepared films varies from 1.62 to 2.06 eV. Hall effect measurement proves the p-type nature for all the deposited films. Samples deposited at 350°C shows carrier concentration of 10²¹ cm⁻³ and electrical conductivity of 526 S cm⁻¹. Solar cell device structure of <ITO/AZO/i-ZnO/CZS/Al> has been fabricated using the CZS sample deposited at 350°C. The cell parameters obtained are V_oc = 0.505 V, I_sc = 4.97 mA/cm², FF = 64.28% and η = 1.6 ± 0.05%.     

Highly-stable,bifunctional, binder-free & stand-alone photoelectrode (FexNi1-xO@a-CC) for natural waters splitting into hydrogen

Photoelectrochemical (PEC) water splitting is a promising approach to boost green hydrogen production. Herein, we prepared novel binder-free photoelectrode by direct growth of iron doped nickel oxide catalyst over activated carbon cloth (Fe_xNi_1-xO@a-CC) having band gap energy of 2.2 eV for overall water splitting. Fe_xNi_1-xO@a-CC photoelectrode had shown remarkable lower potential of only 1.36 V for oxygen evolution reaction (OER) to reach 10 mA cm^?2 current density using very low photonic intensity of 8.36 × 10^?4 E/L.s. For the first time, we also reported electrical efficiency required for PEC water splitting for 1 m³ of water that is equal to 0.09 kWh/m³. Fe_xNi_1-xO@a-CC photoelectrode also exhibits low potentials of 1.44 V (OER) and ?0.210 V (HER) at 10 mA cm^?2 to split sea water. Our results confirmed that designing Fe_xNi_1-xO@a-CC photoelectrode would be an innovative step to widen green energy conversion applications using natural waters (both sea and fresh water).     

High photocatalytic performance for hydrogen production under visible light on the hetero-junction Pani-ZnO nanoparticles

The present work is devoted to the preparation of the hetero-junction of Polyaniline-Zinc oxide nanoparticles (Pani-ZnO_Nps) and its photo-electrochemistry to assess its photocatalytic properties for the water reduction into hydrogen. The semiconducting characterization of the Pani-ZnO_Nps synthetized by in situ chemical oxidative polymerization was studied for the hydrogen evolution reaction (HER) upon visible light illumination. The forbidden bands E_g (= 1.64 eV, Pani) and (3.20 eV, ZnO_NPS) were extracted from the UV–Visible diffuse reflectance data. The Electrochemical Impedance Spectroscopy (EIS) showed the predominance of the intrinsic material with a bulk impedance of 71 kΩ cm². The semi conductivity was demonstrated by the capacitance measurements with flat band potentials (E_fb = - 0.7 and - 0.3 V_SCE) and carriers concentrations (N_A = 1.77 × 10¹⁹ and N_D = 4.80 × 10²⁰ cm^?3) respectively for Pani and ZnO_NPS. The energetic diagram of the hetero-junction Pani-ZnO_Nps predicts electrons injection from Pani to ZnO_NPS in KOH electrolyte. An improvement of 78% for the evolved hydrogen was obtained, compared to Pani alone; a liberation rate of 61.16 μmol g^?1 min^?1 and a quantum yield of 1.15% were obtained. More interestingly, the photoactivity was fully restored after three consecutive cycles with a zero-deactivation effect, indicating clearly the reusability of the catalyst over several cycles.