PS Layer Research Articles

Proximal and remote sensing – what makes the best farm digital soil maps?

Context Digital soil maps (DSM) across large areas have an inability to capture soil variation at within-fields despite being at fine spatial resolutions. In addition, creating field-extent soil maps is relatively rare, largely due to cost. Aims To overcome these limitations by creating soil maps across multiple fields/farms and assessing the value of different remote sensing (RS) and on-the-go proximal (PS) datasets to do this. Methods The value of different RS and on-the-go PS data was tested individually, and in combination for mapping three different topsoil and subsoil properties (organic carbon, clay, and pH) for three cropping farms across Australia using DSM techniques. Key results Using both PS and RS data layers created the best predictions. Using RS data only generally led to better predictions than PS data only, likely because soil variation is driven by a number of factors, and there is a larger suite of RS variables that represent these. Despite this, PS gamma radiometrics potassium was the most widely used variable in the PS and RS scenario. The RS variables based on satellite imagery (NDVI and bare earth) were important predictors for many models, demonstrating that imagery of crops and bare soil represent variation in soil well. Conclusions The results demonstrate the value of combining both PS and RS data layers together to map agronomically important topsoil and subsoil properties at fine spatial resolutions across diverse cropping farms. Implications Growers that invest in implementing this could then use these products to inform important decisions regarding management of soil and crops.

Highly crystalline, highly stable n-type ultrathin crystalline films enabled by solution blending strategy toward organic single-crystal electronics

The development of n-type semiconductor is still far behind that of p-type semiconductor on account of the challenges in enhancing carrier mobility and environmental stability. Herein, by blending with the polymers, n-type ultrathin crystalline thin film was successfully prepared by the method of meniscus-guided coating. Remarkably, the n-type crystalline films exhibit ultrathin thickness as low as 5 nm and excellent mobility of 1.58 cm2 V−1 s−1, which is outstanding in currently reported organic n-type transistors. Moreover, the PS layer provides a high-quality interface with ultralow defect which has strong resistance to external interference with excellent long-term stability, paving the way for the application of n-type transistors in logic circuits.

Effects of Thermal Oxidation on Sensing Properties of Porous Silicon

We report the effects of thermal oxidation on the sensing properties of porous silicon. Porous silicon substrates were prepared by electrochemical etching and thermally oxidized at different temperatures. A comparative EDS analysis shows that porous surfaces oxidized at higher temperatures have higher oxygen-to-silicon ratios. Our results indicate that the chemoresistive response due to the presence of isopropanol vapors at room temperature also increases with an increasing oxidation temperature. The presence of oxygen atoms in the PS layer could both protect the sensor from further atmospheric oxidation and increase its sensitivity.

Morphology and Optical Properties of Nanostructure Porous Silicon Prepared by Electrochemical Etching for Solar Cells Application

In this work, nanostructure porous silicon surface was prepared using electrochemical etching under different current densities. I have studied the surface morphology and photoluminsense of four samples prepared at current densities 5 , 10 , 15 and 20 mA/cm2at fixed etching time 10 min.photoluminsense study showed that the energy gap of the porous silicon samples are is 3.1eV,and it was higher than the energy gap of bulk silicon which was 1.08 eV. A scanning electron microscope (SEM) micrographs were used to estimate the surface area. The surface area of the porous layer is strongly dependent on the porous layer geometry and its depth. The optical reflectance measurements were obtained by using an optical reflectometer (UV) which is equipped with an integrating sphere in the (200-1100) nm wavelength range, which reveals that the textured cells with PS layer sources have lower reflectivity value compared to the textured cell without PS structure.

Unprecedented cell structure variation in multilayered alternating PS/PMMA foams

The objective of the present work was to study the cell structure variation in multilayered alternating polystyrene/poly(methyl methacrylate) (PS/PMMA) foams with the increase of the layer number. The multilayered PS/PMMA foams were prepared via the combination of the co-extrusion technique and the subsequent batch foaming process with carbon dioxide (CO2) as the foaming agent. Controlled with the layer-multiplying elements (LMEs) in the co-extrusion system, multilayered alternating PS/PMMA stacks with various layers (8, 16, 32, 64 and 128) were prepared. It is found that with the increase in layer number, three types of cell structures were observed: the alternating big-cell/small-cell layers, alternating foam/film layers, and the almost uniform cell structure. It is believed that the layer thickness is a crucial factor in governing the formation and hence the variation of the cell structure. For a higher layer thickness, the foaming of the adjacent PS and PMMA layers are independent on each other, thus generating the alternating big-cell/small-cell layers. For a relatively thin layer thickness, the probable gas transfer from the PMMA layers to PS layers during foaming would hinder the formation of the small cells in PMMA, thus bringing the alternating foam/film layers, i.e., bricklaying-like structure. For a very thin layer thickness, the heterogeneous cell nucleation induced by the incompatible interfaces would be favorable for formation of the uniform cell structure.

Distributions of Deuterated Polystyrene Chains in Perforated Layers of Blend Films of a Symmetric Polystyrene-block-poly(methyl methacrylate)

We have examined the spatial distributions of polymer chains in blend films of weakly segregated polystyrene-block-poly(methyl methacrylate) [P(S-b-MMA)] and deuterated polystyrene (dPS). By fine-tuning the composition (ϕPS+dPS = 63.8 vol %) of the total PS/dPS component and annealing temperature (230 and 270 °C), P(S-b-MMA)/dPS blend films mainly form perforated layers with a parallel orientation (hereafter PLs//). The distributions of dPS in PLs// were probed by grazing-incidence small-angle neutron scattering (GISANS) and time-of-flight neutron reflectivity (ToF-NR). GISANS and ToF-NR results offer evidence that dPS chains preferentially locate at the free surface and within the PS layers for blend films that were annealed at 230 °C. Upon annealing at 270 °C, dPS chains distribute within PS layers and perforated PMMA layers. Nevertheless, dPS chains still retain a surface preference for thin films. In contrast, such surface segregation of dPS chains is prohibited for thick films when annealed at 270 °C.

Synthesis and characterization of carbon nanotube doped with zinc oxide nanoparticles CNTs-ZnO/PS as ethanol gas sensor

Nanocomposites have the potential to produce very selective, stable, and sensitive sensors. Nanocomposites porous structures have a larger surface area for gas molecule adsorption. In this paper, the high quality gas sensor was prepared by modified porous layer of silicon (PS) with a thin layer of carbon nanotube (CNTs) and carbon nanotube doped with zinc oxide (ZnO) nanoparticles (70–30)% respectively. PS samples were created using the photoelectrochemical etching method (PECE), for N-type silicon (Si) wafer with resistivity of (1.5–4) Ω cm and a thickness (580 ± 0.25) μm. Three etching current densities were employed for prepare PS layers 12, 24, and 30 mA/cm2, while, the hydrofluoric acid HFc concentration of 40% and etching time was about 10 min. The Structure characteristics, morphological features, and surface chemical bond formation of all PS and (MWCNTs-ZnO/PS) samples were examined using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and Transition Electron Microscope (TEM). All PS and MWCNTs-ZnO/PS samples were applied as ethanol gas sensors at room temperature. The results revealed that CNTs-ZnO/PS had the highest sensitivity to ethanol gas at etching current density 30 mA/cm2, reaching about (2.004984) at a concentration of 500 ppm. Fusion of CNTs-ZnO leads to the emergence of new properties and unique effects, and as a result of the excellent sensing ability of carbon nanotubes in detecting different gases at room temperature, Used in the manufacture of highly selective gas sensors that operate at room temperature. The Interest of this article return to study the effect of extremely high surface to volume ratio (increasing surface area), and ease composition and compatibility with modern silicon microelectronics manufacturing technologies.

EFFECT OF COMPOSITION VARIATION ON CRYSTAL SIZE OF MnO-Fe₂O₃/PS NANOCOMPOSITE LAYER AS SELF CLEANING

This research is based on the abundance of natural materials such as manganese and iron ore. Manganese is usually used for metal coating and has durability so that it is rich in properties to be used for various purposes in the chemical, pharmaceutical, and technological industries. Meanwhile, iron ore is a stable type of oxide so that it has strong properties and is not easily corroded. This research is a type of experimental research conducted at the Laboratory of Material Physics and Biophysics Faculty of Mathematics and Natural Sciences (FMIPA), Padang State University (UNP), and the Chemistry Laboratory of FMIPA UNP. The tools used are HEM-3D, XRD, and UV-VIS. The precursors were prepared by varying the composition of the ratio of MnO-Fe₂O₃ and PS respectively 0,2:0,2:1 ; 0,4:0,4:1 ; 0,6:0,6:1 ; 0,8:0,8:1 ; 1:1:1. This coating is made by means of the spin coating method and uses a temperature of 60 ° using a oven. The results of this study are the maximum crystal size obtained in MnO is 61.26 nm, Fe₂O₃ is 50.45 nm, and MnO-Fe₂O₃ is 53.08 nm. Also, the maximum% degradation produced is 65.97% in a methyl orange solution, this shows that the MnO-Fe₂O₃/PS layer is well degraded. This degradation ability is known as self cleaning because it is able to break down dirt.

Enhancement of the photovoltaic performance of dye-sensitized solar cell using porous silicon layer as photoelectrode

Porous Silicon Dye-sensitized solar cell (PS-DSSC) with N719 Dye was employed as photoelectrode. PS layers were formed on textured crystalline silicon CZ-Si (100) by electrochemical etching (ECE) in hydrogen fluoride (HF) based electrolyte at constant current density for different etching times. The morphological properties of the PS were investigated by scanning electron microscopy (SEM). The optical properties of the textured surfaces are studied using photoluminescence (PL) and reflectivity measurements. The bandgaps of PS from UV-Vis and PL measurements increase to 1.9 eV. The Current-Voltage (I-V) characteristics show that the short-circuit current density Jsc and the open-circuit voltage Voc increased as the porosity of the PS layer increased. These results show an improvement in the efficiency of PS-DSSC.

Nematic Phase of Plate-like Semicrystalline Block Copolymer Single Crystals in Solution Studied by Small-Angle X-Ray Scattering.

Crystalline block copolymers have been used to prepare plate-like colloidal systems with well-controlled size, shape, and size distribution. The isotropic-to-nematic (I-N) phase transition of the novel plate-like colloidal particle suspensions has been reported previously. In this work, we focus on the characterization of the solution structure of the crystals and the N-phase using small- and ultrasmall-angle X-ray scattering techniques (SAXS/USAXS). The system has polystyrene-block-poly(l-lactide) (PS-b-PLLA) block copolymer single crystals (BCSCs) with different sizes dispersed in p-xylene. These crystals are truncated lozenge in shape and have effective diameters ranging from 550 to 4000 nm with a uniform dry thickness of 18.0 nm. Scattering of the individual crystal in solution can be simplified using a disc model with a core layer of 9-10 nm due to the lower contrast of the tethered PS layer. BCSC suspensions filled in thin quartz capillaries are prepared for monitoring the structural information. SAXS measurements of the isotropic phase show a strong face-to-face correlation, indicating that platelets form small stacked clusters in solutions. The isotropic phase is thus a coexistence of single crystals and the stacked multiple-layered clusters. The face-to-face spacing, d, in the N phases is around 75-90 nm, which increases slightly upon increasing the size of crystals. For a given system, the spacing does not change with increasing concentration under the current experimental conditions. Finally, the possible formation of lamellar domains within the N phase is also discussed due to the lateral attraction of this system. These results demonstrate the importance of the lateral attraction between the polar crystalline PLLA blocks on the formation of the N phase: the BCSCs self-assemble into larger sheets via the lateral attraction, which further enhances the I-N transition.

Changes in Retinal Structure and Ultrastructure in the Aged Mice Correlate With Differences in the Expression of Selected Retinal miRNAs.

Age and gender are two important factors that may influence the function and structure of the retina and its susceptibility to retinal diseases. The aim of this study was to delineate the influence that biological sex and age exert on the retinal structural and ultrastructural changes in mice and to identify the age-related miRNA dysregulation profiles in the retina by gender. Experiments were undertaken on male and female Balb/c aged 24 months (approximately 75–85 years in humans) compared to the control (3 months). The retinas were analyzed by histology, transmission electron microscopy, and age-related miRNA expression profile analysis. Retinas of both sexes showed a steady decline in retinal thickness as follows: photoreceptor (PS) and outer layers (p < 0.01 for the aged male vs. control; p < 0.05 for the aged female vs. control); the inner retinal layers were significantly affected by the aging process in the males (p < 0.01) but not in the aged females. Electron microscopy revealed more abnormalities which involve the retinal pigment epithelium (RPE) and Bruch’s membrane, outer and inner layers, vascular changes, deposits of amorphous materials, and accumulation of lipids or lipofuscins. Age-related miRNAs, miR-27a-3p (p < 0.01), miR-27b-3p (p < 0.05), and miR-20a-5p (p < 0.05) were significantly up-regulated in aged male mice compared to the controls, whereas miR-20b-5p was significantly down-regulated in aged male (p < 0.05) and female mice (p < 0.05) compared to the respective controls. miR-27a-3p (5.00 fold; p < 0.01) and miR-27b (7.58 fold; p < 0.01) were significantly up-regulated in aged male mice vs. aged female mice, whereas miR-20b-5p (−2.10 fold; p < 0.05) was significantly down-regulated in aged male mice vs. aged female mice. Interestingly, miR-27a-3p, miR-27b-3p, miR-20a-5p, and miR-20b-5p expressions significantly correlated with the thickness of the retinal PS layer (p < 0.01), retinal outer layers (p < 0.01), and Bruch’s membrane (p < 0.01). Our results showed that biological sex can influence the structure and function of the retina upon aging, suggesting that this difference may be underlined by the dysregulation of age-related mi-RNAs.

Biodegradable sandwich-architectured films derived from pea starch and polylactic acid with enhanced shelf-life for fruit preservation

The development of biopolymer films is crucial for the replacement of conventional plastics. Tremendous effort is made to improve their performances by introducing biopolymers through the film manufacturing process. Herein, a sandwich-architectured film was proposed to efficiently improve the adhesion between the PS and PLA layers by using octenyl succinic anhydride-modified pea starch (OMPS) layer as the interlayer, leading to a highly mechanically enhanced interpenetrating network. Accordingly, the properties of the films were enhanced due to the synergism effect of sandwich architecture. In particular, the WVP value of the sandwich-architectured films (0.25 ∼ 0.89×10−10g·m-1·s-1·Pa-1) decreased more than 7-fold compared with the OMPS20 film, and the OP value of the sandwich-architectured films (0.256 ∼ 1.229×10-12cm3·m·m-2·s-1·Pa-1) decreased more than 10-fold in comparison to the PLA film. Benefitting from the characteristics investigated above, the films exhibited a favorable effect on strawberry storage. Overall, the fabricated eco-friendly sandwich-architectured films have shown great potential for biodegradable packaging applications.

Distinct band UV–Visible photo sensing property of ZnO-Porous silicon (PS):p-Si hybrid MSM heterostructure

Present article deals with fabrication of UV–Visible radiation sensing photodetector (PD) by architecting planar and sandwiched (PD1 and PD2) electrode configurations on ZnO-PS:p-Si heterostructure. PS:p-Si structure is prepared by electrochemical anodization method. Thin ZnO layer of ~162 nm is deposited on PS:p-Si substrate using pulsed DC magnetron sputtering technique. Gold (Au) is combined with Aluminium (Al) to provide rectifying Schottky contacts to the devices. Prior to device testing it is tested for various conventional characterizations. FESEM studies confirm uniform deposition of nanocrystalline ZnO thin film with mean particle size of ~ 35 nm, whereas its cross section shows uniform interface between ZnO and PS with combined thickness of ~700 nm. Cross sectional EDX analysis confirms diffusion of ZnO particles into PS layer. UV–vis absorption spectrum gives bandgap of ZnO as ~3.3 eV. Reflectance measurement of the heterostructure shows decrease in reflectivity compared to bulk c-Si with ZnO-PS:p-Si showing multiple interference pattern compared to bare ZnO coated on glass within the spectral range 200 nm-800 nm. The pattern is remarkably increased compared to that of PS:p-Si. Photoluminescence study reveals various luminescence bands peaked at ~378 nm, 388 nm, 398 nm, 410 nm, 420 nm, 433 nm, 450 nm, 467 nm, 482 nm 492 nm and 597 nm. Current- Voltage (I–V) measurement for dark current (Id) gives low leakage current of the devices PD1 and PD2 respectively as 6.6×10−8A and 7.5×10−7A at -5V, which is however an order of magnitude more than the ZnO coated one on glass. Both the devices PD1 and PD2 show UV–Visible photoresponse, whereas the ZnO device on glass shows response to UV (375 nm) only. Both the devices show response time ~1 s in visible range which is nearly half the value in UV range.

Distinct and enhanced ultraviolet to visible ZnS-porous silicon (PS):p-Si hybrid metal-semiconductor-metal (MSM) photodetector

Present article reports distinct and enhanced ultraviolet to visible light sensing property of metal-semiconductor-metal (MSM) based ZnS-PS:p-Si hybrid heterostructure. PS:p-Si heterostructure is prepared using electrochemical anodization technique by alternate variation of etching current density within the limit of 17.2–22.1 mA cm−2. ZnS (99.99% purity) in powder form is deposited on PS:p-Si surface via thermal evaporation technique under a chamber pressure of 2 × 10−5 m bar. To achieve MSM configuration Au electrode of ∼8 nm and Al electrode of ∼22 nm thickness are successively coated on top of ZnS-PS:p-Si surface using a shadow mask with dimension of 6 × 6 mm. Morphological features of the heterostructure are observed and analysed using cross section FESEM. This gives thickness of the deposited ZnS layer as around ∼110 nm on ∼540 nm thick PS:p-Si structure. These also confirm uniform interface between the two i.e, ZnS and PS:p-Si layers. Cross sectional EDX analysis indicates diffusion of ZnS particles into the PS layer. Optical analysis observed via UV–Visible spectroscopy gives bandgap (obtained through Tauc plot) of the bare ZnS film to be 3.4 eV with 70–90% transparency in the visible region (390–700 nm). Optical reflectance spectrum of the prepared heterostructure shows decreased reflectivity compared to that of the bare PS:p-Si structure which is itself 20–30% less compared to bulk silicon. Spectral response measured for the wavelength range of 200–500 nm gives distinct and enhanced responsivity peak values of ∼0.94 and ∼1.12 AW−1 at 365 nm (UV) and 400 nm (visible) compared to ∼0.5 AW−1 (maximum at 400 nm) of bare PS:p-Si MSM structure for bias voltage of −4 V. The response and recovery times of the heterostructure are found to be 0.54 ± (4.3×10-4) s, 0.38±9.5×10-5 s and 0.50±2.8×10-4 s, 0.35±6.5×10-5 s under UV and visible irradiations.

Wettability Control of Interfaces for High-Performance Organic Thin-Film Transistors by Soluble Insulating Polymer Films.

Organic small-molecule semiconductors have higher carrier mobility compared to polymer semiconductors, while the actual performances of these materials are susceptible to morphological defects and misalignment of crystalline grains. Here, a new strategy is explored to control the crystallization and morphologies of a solution-processed organic small-molecule semiconductor 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) using soluble polymer films to control the wettability of substrates. Different from the traditional surface modification method, the polymer layer as a modification layer is soluble in the semiconductor solution during the fabrication of organic thin-film transistors (OTFTs). The dissolved polymer alters the state of the semiconductor solution, which in turn, changes the crystallographic morphologies of the semiconductor films. By controlling the solubility and thickness of the polymer modification layers, it is possible to regulate the grain boundary and domain size of C8-BTBT films, which determine the performances of OTFTs. The bottom-gate transistors modified by a thick PS layer exhibit a mobility of >7 cm2/V·s and an on/off ratio of >107. It is expected that this new modification method will be applicable to high-performance OTFTs based on other small molecular semiconductors and dielectrics.

Impact of Nanoconfinement on Polylactide Crystallization and Gas Barrier Properties.

The barrier properties of poly(l-lactide) (PLLA) were investigated in multinanolayer systems, probing the effect of confinement, the compatibility between the confining and the confined polymer, crystal orientation, and amorphous phase properties. The multilayer coextrusion process was used to confine PLLA between two amorphous polymers (polystyrene, PS; and polycarbonate, PC), which have different chemical affinities with PLLA. Confined PLLA layers of approximately 20 nm thickness were obtained. The multinanolayer materials were annealed at different temperatures to obtain PLLA crystallites with distinct polymorphs. PLLA annealed in PC/PLLA films at 120 °C afforded a crystallinity degree up to 65%, and PLLA annealed in PC/PLLA or PS/PLLA films at 85 °C had a crystallinity degree of 45%. WAXS measurements evidenced that the PLLA lamellas between PS layers had a mixed in-plane and on-edge orientation. PLLA lamellas between PC layers were uniquely oriented in-plane. DMA results evidenced a shift of the PC glass transition toward lower temperature, suggesting the possible presence of an interphase. The development of the rigid amorphous fraction (RAF) in the amorphous phase during annealing was impacted by the confiner polymer. The RAF content of semicrystalline PLLA was about 15% in PC/PLLA, whereas it was neglectable in PS/PLLA. The oxygen barrier properties appeared to be governed by RAF content, and no impact of the PLLA polymorph or the crystalline orientation was observed. This study shows that the confinement of PLLA on itself does not impact barrier properties but that the proper choice of the confiner polymer can lead to decrease the phase coupling which creates the RAF. It is the prevention of RAF that decreases permeability.

Fabrication of periodic nano-porous surface structure for highly sensitive gravimetric quartz crystal applications

A periodic nano-porous surface on quartz crystal electrodes was carefully fabricated for increasing the mass-sensitive areas. Detailed porous structures were prepared by analyzing Au electrochemical reduction process of PS layer coated quartz crystals. The sensitivity measurement of the porous quartz crystals was performed with several traditional methods, and an optimized reduction time for higher sensitivity was determined. The frequency shift of the nano-porous quartz crystals showed 10 times bigger change with the same concentration of target solutions in self-assembly procedures. In the procedures, the freshly increased surface portion did not produce additional molecular slip-effects on the measured resonant resistance values, thus, the periodic porous chips showed another side merit for the mass sensor applications. We propose a possible use of the current porous surface as a platform for developing other high-performance sensors and analyses.

Hypochlorite responsive ratiometric fluorescent switch and logic gates based on lanthanide functionalized polymer nanosphere

A novel ratiometric fluorescent nanoprobe (Eu(NTA)3L@PS) based on lanthanide functionalized polymer nanosphere has been designed and prepared through a typical miniemulsion polymerization process. Eu(NTA)3L@PS displays a strong red emission in aqueous environment due to the protection of PS layer. The red fluorescence (λem = 618 nm) will gradually quench and the green emission (λem = 496 nm) increase toward ClO− in the presence of H+. The fluorescence intensity ratio (F618/F496) can accurately monitor ClO− concentration with the low limit of detection (57.3 nM). Moreover, Eu(NTA)3L@PS can be used as an optical logic device for “AND” logic gate with ClO− and H+ as two inputs, red and green emission as two outputs.

Thermal, Rheological and Mechanical Properties of PETG/rPETG Blends

This paper presents the reuse process of post-consumer printed foils made of glycol-modified poly(ethylene terephthalate) (PETG). Fourier-transform infrared spectroscopy and a scanning electron microscope confirmed that these foils consist of PETG and PS layers. Firstly, foil pieces were immersed in the organic solution to remove all prints and after washing and drying they were extruded into regranulate rPETG pellets. Three types of PETG/rPETG blends were fabricated with the addition of 10, 20 and 30 wt% of virgin PETG. Microscopic analysis of the blends confirmed their homogeneity, as was also shown by the fact that there was only one glass transition peak in the heating curve given by differential scanning calorimetry. Moreover, in the presence of fresh PETG the degradation temperatures of rPETG improved significantly, and the viscosity of all blends was reduced as a result of shortened macromolecule chains in rPETG. Mechanical analysis of the materials showed that all blends have comparable tensile strength and a Young’s modulus that is higher than rPETG but lower than virgin PETG. Elongation at break decreases together with the content of rPETG.

The role of etching current density and porous structure on enhanced photovoltaic performance of ZnO/PS heterojunction solar cells

The paper reports the fabrication of zinc oxide/porous silicon (ZnO/PS) heterojunction solar cells based on porous material and the effects of etching current density and porous structure on the performance of these solar cells. PS samples were produced by electrochemical etching on a p-type crystalline-silicon (c-Si) wafer with boron (B) doped and (111) orientation. The etching process was carried out in a HF:C2H5OH (1:3) electrolyte solution at different etching current densities of 5, 10, 15, and 25 mA/cm2 for 15 min at room temperature (RT). ZnO nanoparticles synthesized by sol–gel method were coated on PS layers by the sol–gel spin coating technique at a speed of 300 rpm for 20 s at RT for fabrication of ZnO/PS heterojunction solar cells. The structural analyses were performed using a field emission scanning electron microscope. Depending on the increase of etching current density, the pore diameter and porosity in the etched structures increased approximately from 200 to 920 nm and from 19 to 62%, respectively. Reflection characteristics of ZnO/PS heterojunction solar cells were determined using reflection measurements. The lowest optical reflection was obtained in ZnO/PS heterojunction solar cell with PS layer formed at high etching current density. The dark I–V measurements indicated that all the solar cells exhibited a typical rectifying behavior, and the ideality factor increased with the increase of etching current density. Light I–V measurements were performed under AM1.5G conditions. The short circuit current, open circuit voltage, and energy conversion efficiency (η) increased with the increase of etching current density. The best photovoltaic performance was obtained in ZnO/PS heterojunction solar cell having the PS layer produced at high etching current density of 25 mA/cm2. The highest energy conversion efficiency of 6.05% was obtained in this solar cell. It was determined that the etching current density and porous structure are important parameters affecting the photovoltaic performance of ZnO/PS heterojunction solar cells.