FF Values Research Articles

Impact of absorber layer thickness and defect density on the performance of MAPbI3 solar cells based on CuO2 as hole transport material

Perovskite solar cells are a promising next-generation solar energy harvester because of their excellent photovoltaic performance and simple fabrication procedure. The high power conversion efficiency of this cell, together with its low cost of materials and processes, differentiates it from commercial silicon or other organic and inorganic solar cells. In this work, numerical simulation was performed using Solar Cell Capacitance Simulator (SCAPS)−1D for the device structure (FTO/HTM/ CH3NH3PbI3/ETM/Au) to analyze the impact of absorber layer thickness and defect density on various parameters of Photovoltaic cells. The purpose of this research was to explore the properties of CH3NH3PbI3-based solar cells with different HTM layers, such as Cu2O and ETM layers, such as SnO2, TiO2, and ZnO, respectively. Additionally, the thicknesses of the perovskite absorber are adjusted to obtain the highest photovoltaic efficiency, and the impact of the defect at the perovskite absorber layer on solar cell performance is also investigated. According to the findings of this article, the thickness of the absorber layer and defect density in a perovskite solar cell had a significant impact on JSC, FF, VOC, and efficiency. The findings show a substantial gain in efficiency (18%) when the ETM layer is ZnO. As the defect density of the absorber layer increases, the JSC, VOC, FF, and PCE values of perovskite solar cells decrease considerably. According to our findings, the ZnO as ETM is the most likely to provide a high photovoltaic (PV) efficiency when combined with Cu2O-based HTM.

Manipulating the Alkyl Chains of Naphthodithiophene Imide-Based Polymers to Concurrently Boost the Efficiency and Stability of Organic Solar Cells.

Morphology instability holds the major responsibility for efficiency degradation of organic solar cells (OSCs). However, how to develop polymer donors simultaneously with high efficiency and excellent morphology stability remains challenging. Herein, we reported naphtho[2,1-b:3,4-b']dithiophene-5,6-imide (NDTI)-based new polymers PNDT1 and PNDT2. The alkyl chain engineering leads to high crystallinity, high hole mobility (>10-3 cm2 V-1 S-1), and nanofibrous film morphology, which enable PNDT2 to exhibit an efficiency of 18.13% and a remarkable FF value of 0.80. Moreover, the NDTIs have short π-π stacking and abundant short interactions, and their polymers exhibit superior morphological stability. Therefore, the PNDT2-based OSCs exhibit much better device stability than that of PNDT1, PAB-α, and benchmark polymers PM6 and D18. This work suggests the great importance of the large conjugated backbone of the monomer and alkyl chain engineering to develop high-performance and morphology-stable polymers for OSCs.

Evaluation of renal function in chronic kidney disease (CKD) by mDIXON-Quant and Amide Proton Transfer weighted (APTw) imaging

BackgroundChronic kidney disease (CKD) is a long-term condition that affects >10% of the adult population worldwide. Noninvasive assessment of renal function has important clinical significance for disease diagnosis and prognosis evaluation. ObjectiveTo explore the value of mDIXON-Quant combined with amide proton transfer weighted (APTw) imaging for accessing renal function in chronic kidney disease (CKD). Materials and methodsTwenty-two healthy volunteers (HVs) and 30 CKD patients were included in this study, and the CKD patients were divided into the mild CKD (mCKD) group (14 cases) and moderate-to-severe CKD (msCKD) group (16 cases) according to glomerular filtration rate (eGFR). The cortex APT (cAPT), medulla APT (mAPT), cortex R2⁎ (cR2⁎), medulla R2⁎ (mR2⁎), cortex FF (cFF) and medulla FF (mFF) values of the right renal were independently measured by two radiologists. Intra-group correlation coefficient (ICC) test was used to test the inter-observer consistency. The analysis of variance (ANOVA) was used to compare the difference among three groups. Mann-Whitney U test was used to analyze the differences of R2⁎, FF and APT values among the patient and HV groups. Area under the receiver operating characteristic (ROC) curve (AUC) was used to analyze the diagnostic efficiency. The corresponding threshold, sensitivity, and specificity were obtained according to the maximum approximate index. The combined diagnostic efficacy of R2⁎, FF, and APT values was analyzed by binary Logistic regression, and the AUC of combined diagnosis was compared with the AUC of the single parameter by the Delong test. ResultsThe cAPT value of the HV, mCKD and msCKD groups increased gradually. The mAPT value and cR2⁎ values of the mCKD and msCKD groups were higher than those of the HV group, while the mFF value of the mCKD group was lower than HV group (all P < 0.05). The cAPT and mAPT values showed good diagnostic efficacy in evaluating different degrees of renal damage, while cR2⁎ and mFF values showed moderate diagnostic efficacy. When combining the APT, R2⁎, and FF values, the diagnostic efficiency was significantly improved. ConclusionmDIXON-Quant combined APTw imaging can be used for improved diagnosis of CKD.

High-efficiency n-TOPCon bifacial solar cells with selective poly-Si based passivating contacts

Improving the conversion efficiency of n-TOPCon solar cell is still a hot topic. The selective poly-Si based passivating contacts (Poly-SEs) are ideal candidates for reducing the parasitic absorption and contact resistivity of n-type silicon solar cells and for providing better current collection. In this work, we used LPCVD and the POCl3 tube furnace diffusion methods to fabricate the selective poly-Si based passivating contacts, and studied the influences of key process parameters of the SiOx layer formation process (the oxidation duration (toxidation) and the constant pressure duration (tpressure)), and POCl3 tube diffusion process parameters (the POCl3-N2 carrier gas flow rate at the deposition, deposition temperature, drive-in temperature) on the n+-poly-Si profiles, recombination current density (J0), contact resistivity (ρc) of n-TOPCon solar cells. The results showed that the toxidation and tpressure had a significant impact on J0 and ρc which were mainly related to the distribution number of O and Si4+ content on the growth of the SiOx layer. And the influence of the drive-in temperature of phosphorus (P) diffusion process on J0 value is stronger than that of the deposition temperature, which was mainly related to the chemical passivation of SiOx layer induced by P-indiffusion into Si at high temperature. The reduction in the thickness of poly-Si from 110 nm to 30 nm led to an increase in the short-circuit current density (Jsc) per nanometer of ∼0.0093 mA/cm2 per nm. The Poly-SEs were fabricated by 3D printing mask technology and secondary LPCVD/phosphorus diffusion with J0, n+ ≈ 5 fA/cm2 (n+-poly-Si layer ≈ 50 nm) and J0, metal,n++ ≈ 73.8 fA/cm2 (n++-poly-Si layer ≈ 110 nm), and the efficiency was improved by 0.12% owing to the increase in Jsc value of 0.28 mA/cm2. After optimizing the passivation process, the industrial-grade TOPCon bifacial cells reached an efficiency (Eff), Voc, Jsc, and FF values as high as 25.4%, 721 mV, 42.2 mA/cm2, and 83.5%, respectively.

Effect of Wiper Edge Geometry on Machining Performance While Turning AISI 1045 Steel in Dry Conditions Using the VIKOR-ML Approach

AISI 1045 can be machined well in all machining operations, namely drilling, milling, turning, broaching and grinding. It has many applications, such as crankshafts, rollers, spindles, shafts, and gears. Wiper geometry has a great influence on cutting forces (Fr, Ff, Fc and R), temperature, material removal rate (MRR) and surface roughness (Ra). Wiper inserts are used to achieve good surface quality and avoid the need to buy a grinding machine. In this paper, an optimization-based investigation into previously reported results for Taguchi’s based L27 orthogonal array experimentations was conducted to further examine effect of the edge geometry on the turning performance of AISI 1045 steel in dry conditions. Three input parameters used in current research include the cutting speed (Vc), feed (f) and depth of cut (ap), while performance measures in this research were Ra, Fr, Ff, Fc, R, temperature (temp) and MRR. The Vise Kriterijumska Optimizacija Kompromisno Resenje (VIKOR) method was used to normalize and convert all the performance measures to a single response known as the VIKOR-based performance index (Vi). The machine learning (ML) approach was used for the prediction and optimization of the input variables. A correlation plot is developed between the input variable and Vi using the ML approach. The optimized setting suggested by Vi-ML is Vc: 160 m/min; ap: 1 mm and f: 0.135 mm/rev, and the corresponding value of Vi was 0.2883, while the predicted values of Ra, Fr, Ff, Fc, R, temp and MRR were 2.111 µm, 43.85 N, 159.33 N, 288.13 N, 332,16 N, 554.4 °C and 21,600 mm3/min, respectively.

Contribution and behavioral assessment of physical and anthropogenic factors for soil erosion using integrated deep learning and game theory

Ensuring sustainable management of soil erosion is of utmost importance to prevent its adverse effects. Unfortunately, this issue has received limited attention in the past, therefore, a comprehensive study was undertaken to identify key indicators for soil erosion and develop an Ensemble Deep Neural Network (EDNN) model for predicting soil erosion probability (SEP) zones in the Guwahati urban watershed. To conduct this study, Revised Universal Soil Loss Equation (RUSLE) was employed to estimate potential soil loss (PSL). The study identified 17 physical and landscape parameters as priority factors for soil erosion initiation based on the PSL. These priority variables were analyzed using three hyper-tuned models i.e., Gradient Boosting Machine (GBM), Random Forest (RF), and Deep Neural Network (DNN) within the H2O framework. Furthermore, the study developed EDNN and hyper-tuned DNN models to predict SEP and analyzed the behavior of priority variables in high and low soil erosion probability zones using DNN-based game theory. The findings indicated that the study area experiences soil loss ranging from 140 to 181 tonnes/ha/year. Rainfall, Ff, Dd, slope, and elevation identified as the most critical factors influencing soil erosion. The EDNN model successfully predicted very high and high SEP zones, covering 172.13 km2 and 22.60 km2 respectively. Further, the result shows that high values of drainage density, cohesion, TWI, LULC, and rainfall contribute to significant soil erosion, while low values of slope, SHDI, ED, and Ff act as preventive factors. The study offers valuable insights into the construction of an EDNN model and the integration of deep learning with game theory for robust and scientific soil erosion modeling. The analysis of behavior of the priority parameters provides a novel approach for understanding the impact of individual parameter samples on soil erosion, facilitating the development of effective prevention strategies.

Occurrence and water-sediment exchange of systemic insecticides and their transformation products in an agriculture-dominated basin

Neonicotinoids (NEOs) and fipronil (FIP) are ubiquitous in aquatic environment, yet the transformation and water-sediment exchange are largely unknown for these systemic insecticides and their transformation products (TPs). Herein, occurrence, field-based partitioning coefficients, and fugacity fractions (ff) of NEOs, FIP, and their TPs were analyzed in the drainage and receiving rivers near a rice paddy field. NEOs and FIPs were frequently detected in the sediments with concentrations of TPs being often higher than the parent compounds. Average ff values of NEOs (0.944–1.00) were larger than those of FIPs (0.399–0.716), indicating NEOs had a greater tendency to diffuse from sediment into water. Similar as well-studied hydrophobic compounds, hydrophobicity was the main factor impacting the water-sediment exchange of moderately hydrophobic FIPs. Alternatively, electrostatic interactions governed the fate of hydrophilic NEOs in water-sediment system. The log Kd values of NEOs were positively correlated with their N/C ratios (p < 0.05), possibly because the negatively charged sediments (zeta potential were from −19.1 ± 0.6 to −5.84 ± 0.57 mV) generated electrostatic attraction with amino functional group. Our study highlighted the ubiquitousness of TPs and distinct water-sediment interaction for moderately hydrophobic and hydrophilic insecticides in an agriculture-dominated watershed.

Production and Performance of Dye Sensitive Solar Cells Using Co+2 Doped Photo-Anodes

In order to increase the use of solar energy, which is one of the renewable energy sources, it isto produce high-efficiency, low-cost and environmentally friendly dye-sensitive solar cells from solar cellsprovided by photovoltaic technology that generates electricity from solar energy. Therefore, there is a needto develop new materials and modified designs to produce solar cells at lower cost. One way to increasethe efficiency of dye-sensitized solar cells (DSCC) is by doping at the anode. At the same time, graphenepaste was used instead of Pt cathode to reduce the cost. In this study, pure and Cobalt (Co+2) added TiO2pastes were prepared to produce DSCC. Photovoltaic performances were determined by comparing pureand doped batteries with each other. For this purpose, pure and Co+2 added TiO2 pastes were first prepared.The resulting pastes were applied to FTO glasses with the doctor-blade method. Then, DSCCs wereproduced by sandwiching pure and Co+2 doped TiO2 photoanodes sensitized with N-719 dye with graphenecoated FTO thin films. The performance of the produced DSCCs was determined by Current Density (J) -Voltage (V) analysis. There was a certain increase in FF and Jsc values with doping. However, the resultsshowed that the efficiency value of Co+2 doped batteries is 370% above the value of batteries using pureTiO2 photo-anodes.

SCAPS simulation of novel inorganic ZrS2/CuO heterojunction solar cells

ZrS2 is transition metal dichalcogenides (TMDCs) which is believed one of the most talented applicants to fabricate photovoltaics. Therefore, we present here for the first-time numerical simulation of novel inorganic ZrS2/CuO heterojunction solar cells employing SCAPS-1D. The influence of the thickness, carrier concentration, and bandgap for both the window and absorber layers on the solar cell fundamental parameters was explored intensely. Our results reveal that the solar cell devices performance is mainly affected by many parameters such as the depletion width (Wd), built-in voltage (Vbi), collection length of charge carrier, the minority carrier lifetime, photogenerated current, and recombination rate. The η of 23.8% was achieved as the highest value for our simulated devices with the Voc value of 0.96 V, the Jsc value of 34.2 mA/cm2, and the FF value of 72.2%. Such efficiency was obtained when the CuO band gap, thickness, and carrier concentration were 1.35 eV, 5.5 µm, and above 1018 cm−3, respectively, and for the ZrS2 were 1.4 eV, 1 µm, and less than 1020 cm−3, respectively. Our simulated results indicate that the inorganic ZrS2/CuO heterojunction solar cells are promising to fabricate low-cost, large-scale, and high-efficiency photovoltaic devices.

Efficient Small‐Molecule Organic Solar Cells by Modulating Fluorine Substitution Position of Donor Material

Comprehensive SummaryThe fluorine substitution position in organic semiconductors is critical in improving device performance for organic solar cells (OSCs). Herein, two similar small‐molecule donors, B3T‐PoF and B3T‐PmF, are designed and synthesized, which only differ on the fluorine substitution position on the pendent benzene unit. Although both small‐molecule donors exhibit similar absorption profiles and molecular energy levels, B3T‐PmF has stronger crystallinity and lower energetic disorder than B3T‐PoF. After blending with the non‐fullerene acceptor of BO‐4Cl, B3T‐PmF shows better phase separation and more ordered molecular packing in blend film. As a result, the B3T‐PoF:BO‐4Cl‐based OSC shows a power conversion efficiency (PCE) of 12.3%. In contrast, the B3T‐PmF:BO‐4Cl‐based cell demonstrates obviously increased JSC and FF values, thus yielding an excellent PCE of 14.7%. This study indicates that reasonable selection of fluorine atom substitution position in conjugated side chains is one of the promising strategies for achieving high‐performance SM‐OSCs.

A Multifluorination Strategy Toward Wide Bandgap Polymers for Highly Efficient Organic Solar Cells

AbstractCreating new electron‐deficient unit is highly demanded to develop high‐performance polymer donors for non‐fullerene organic solar cells (OSCs). Herein, we reported a multifluorinated unit 4,5,6,7‐tetrafluoronaphtho[2,1‐b : 3,4‐b′]dithio‐phene (FNT) and its polymers PFNT‐F and PFNT‐Cl. The advantages of multifluorination: (1) it enables the polymers to exhibit low‐lying HOMO (≈−5.5 eV) and wide band gap (≈2.0 eV); (2) the short interactions (F⋅⋅⋅H, F⋅⋅⋅F) endow the polymers with properties of high film crystallinity and efficient hole transport; (3) well miscibility with NFAs that leads to a more well‐defined nanofibrous morphology and face‐on orientation in the blend films. Therefore, the PFNT‐F/Cl : N3 based OSCs exhibit impressive FF values of 0.80, and remarkable PCEs of 17.53 % and 18.10 %, which make them ranked the best donor materials in OSCs. This work offers new insights into the rational design of high‐performance polymers by multifluorination strategy.

A Multifluorination Strategy Toward Wide Bandgap Polymers for Highly Efficient Organic Solar Cells.

Creating new electron-deficient unit is highly demanded to develop high-performance polymer donors for non-fullerene organic solar cells (OSCs). Herein, we reported a multifluorinated unit 4,5,6,7-tetrafluoronaphtho[2,1-b : 3,4-b']dithio-phene (FNT) and its polymers PFNT-F and PFNT-Cl. The advantages of multifluorination: (1) it enables the polymers to exhibit low-lying HOMO (≈-5.5 eV) and wide band gap (≈2.0 eV); (2) the short interactions (F⋅⋅⋅H, F⋅⋅⋅F) endow the polymers with properties of high film crystallinity and efficient hole transport; (3) well miscibility with NFAs that leads to a more well-defined nanofibrous morphology and face-on orientation in the blend films. Therefore, the PFNT-F/Cl : N3 based OSCs exhibit impressive FF values of 0.80, and remarkable PCEs of 17.53 % and 18.10 %, which make them ranked the best donor materials in OSCs. This work offers new insights into the rational design of high-performance polymers by multifluorination strategy.

Prediction of Mechanical Properties of Rubberized Concrete Incorporating Fly Ash and Nano Silica by Artificial Neural Network Technique

The use of enormous amounts of material is required for production. Due to the current emphasis on the environment and sustainability of materials, waste products and by-products, including silica fume and fly ash (FA), are incorporated into concrete as a substitute partially for cement. Additionally, concrete fine aggregate has indeed been largely replaced by waste materials like crumb rubber (CR), thus it reduces the mechanical properties but improved some other properties of the concrete. To decrease the detrimental effects of the CR, concrete is therefore enhanced with nanomaterials such nano silica (NS). The concrete mechanical properties are essential for the designing and constRuction of concrete structures. Concrete with several variables can have its mechanical characteristics predicted by an artificial neural network (ANN) technique. Using ANN approaches, this paper predict the mechanical characteristics of concrete constructed with FA as a partial substitute for cement, CR as a partial replacement for fine aggregate, and NS as an addition. Using an artificial neural network (ANN) technique, the mechanical characteristics investigated comprise splitting tensile strength (Fs), compressive strength (Fc), modulus of elasticity (Ec) and flexural strength (Ff). The ANN model was used to train and test the dataset obtained from the experimental program. Fc, Fs, Ff and Ec were predicted from added admixtures such as CR, NS, FA and curing age (P). The modelling result indicated that ANN predicted the strength with high accuracy. The proportional deviation mean (MoD) values calculated for Fc, Fs, Ff and Ec values were −0.28%, 0.14%, 0.87% and 1.17%, respectively, which are closed to zero line. The resulting ANN model’s mean square error (MSE) values and coefficient of determination (R2) are 6.45 × 10−2 and 0.99496, respectively.

Sewage discharge and organic matter affect the partitioning behaviors of different polycyclic aromatic hydrocarbons in a river surface sediment-pore water system

The partitioning behaviors of persistent organic pollutants (POPs) between sediments and water are significant for their transport and fate in aquatic environments; however, an in-depth understanding is still required. Herein, we studied partitioning coefficients, fugacity fractions (ff), and influencing factors of parent, nitrated, and oxygenated polycyclic aromatic hydrocarbons (PPAHs, NPAHs, and OPAHs, respectively), which are typical POPs composed of multiple aromatic rings, in the surface sediment-pore water system of the Haihe River. The logarithmic organic carbon normalized partitioning coefficient (lgKOC) of PPAHs (4.04 ± 0.80) was evidently greater than those of NPAHs (2.64 ± 1.30) and OPAHs (2.69 ± 0.77). Owing to the effects of the polar groups in NPAHs and OPAHs, their partitioning behaviors were different from that of PPAHs. ff values showed that most PAH species approached dynamic equilibrium. As an important source of riverine PAHs, sewage discharge affected PAHs partitioning, whereas dam interception exerted less impact in this study. lgKOC and ff were negatively correlated with sediment organic matter, represented by particulate organic carbon (POC) and n-alkanes, and positively correlated with the sand fraction in surface sediments. In addition, positive correlations of lgKOC and ff with pH and salinity were observed in pore waters. The results indicate appreciable impacts of sewage discharge and organic matter on the partitioning processes of different PAHs.

A new single-step technique to fabricate transparent hydrophobic surfaces utilizable in perovskite solar cells

We report a simple low-cost novel method for coating an ultrathin hydrophobic film usable for different applications. A hydrophobic layer is fabricated on a TiO2 substrate by hydrolysis of silicone rubber evaporation. The hydrophobic Si (CH3)3 groups bonded to the substrate by the reaction of hydrophilic SiOH groups with the hydroxyl groups on the TiO2 surface. In addition, the silicone film was introduced in a carbon-based perovskite solar cell as a tunneling passivation layer between the electron transport layer and the active layer to reduce interfacial and extraction losses. An improved perovskite layer with better crystallinity, larger grain size, and higher stability was achieved. The optimal energy conversion efficiency was 17.42% with FF, VOC, and JSC values of 73.76%, 1.1 V, and 21.39 mA cm−2, respectively.

Proper annealing process for a cost effective and superhydrophobic ambient-atmosphere fabricated perovskite solar cell

The conversion efficiency of perovskite solar cells has increased rapidly in recent years, however, the balance between sustainability, efficiency and cost has become a serious challenge on the way to a competitive commercial product. Currently, ongoing research is strongly focused on how to effectively combine those issues together. In this work, the sustainability and efficiency were shown to be improved by using a simple low-cost fabrication process: with a single electron transporting layer with low-temperature heat treatment (160 °C), a single-step perovskite layer (Cs0.17FA0.83Pb(I0.83Br0.17)3) fabricated and annealed in air atmosphere, and low-cost imprinted carbon as the upper electrode. The annealing process of the active layer was studied to improve crystallinity and achieve the best grain boundary self-passivation under these conditions. Moreover, to develop sustainability, an easy-to-use superhydrophobic layer with a contact angle of ∼160o was successfully deposited using an invented method. Morphology, crystallization, and optoelectronic properties of the devices were investigated using various measurement methods. It was found that a 15-min annealing at 130 °C is required to obtain an appropriate self-induced passivation layer of PbI2 and a high-performance crystallized active layer with the lowest defect density. An optimum energy conversion efficiency of 17.34% was achieved with FF, VOC and JSC values of 76.43%, 1.04 V, and 21.67 mA cm−2, respectively. It is hoped that these results will provide new perspectives for the commercialization of perovskite solar cells.

Temporal Variations of PCBs and Their Estimated Air-Soil Exchange Fluxes Measured in Seven Sites in Bursa-Turkey

ABSTRACT Polychlorinated biphenyls (PCBs) can travel in ambient air for long distances and exchange between different environments. Soil and ambient air samples were simultaneously gathered during the winter and summer months in 7 regions in Bursa, Turkey, to study spatio-temporal fluctuations and soil-air exchange of PCBs. Σ25 PCB concentrations for the winter and summer seasons were 0.007–0.04 ng/m3 and 0.03–0.24 ng/m3 in air, also 4.09–10.00 ng/g DM and 1.65–10.01 ng/g DM in soil, respectively. PCB concentrations showed spatial variations in air and soil samples. The lowest total PCB levels were measured both in air and soil samples in the R (rural) site. The highest Σ25 PCB concentrations were measured in the SR3 site in soil samples, while the I1 site was the most polluted in air samples. Ambient air concentrations of PCBs in the summer months were greater than those in winter. In SR1, SR2, SR3, and I1 sites, soil PCB levels in the summer were higher than in the winter. The opposite was observed in the other sites (R, U, I2). Net flux values and fugacity fraction (ff) values for all regions indicated that PCBs represented a transfer from soil to air. The air-soil net gas phase flux values changed between 0.04 - 1.01 ng/m2-day and 0.02–0.83 ng/m2-day in the summer and winter, respectively. The PCB homologous distributions of mean flux values differed depending on the regions and seasons. PCBs with 4- and 5-CBs were dominant in both seasons.

TiO2:ZnO/CuO thin film solar cells prepared via reactive direct-current (DC) magnetron sputtering

TiO2:ZnO/CuO thin-film solar cells are manufactured using reactive direct-current magnetron sputtering. For the first time, the TiO2:ZnO layers have been used as an emitter in TiO2:ZnO/CuO solar cells by self-produced Ti-ZnO targets. The structural and morphological characterization of the TiO2:ZnO/CuO solar cells was studied using physical methods of investigation: X-ray diffraction (XRD), scanning electron microscopy (SEM), and current-voltage (I-V) characteristics. From the XRD study, thin films were observed in CuO, ZnO, TiO2 and Ti3O5 phases. Basic morphological characterizations like thickness, mechanism of growth, and average grain sizes were analyzed via scanning electron microscopy. The thicknesses of the TiO2:ZnO and CuO layers were in the range of 170 to 354 nm and from 508 to 1634 nm, respectively. Furthermore, average grain sizes of CuO layers were in the range of 40–150 nm. The I-V study confirms the photovoltaic behavior of TiO2:ZnO/CuO thin-film solar cells. The open-circuit voltage (Voc) and short-circuit current density (Jsc) values of the photovoltaic devices ranged from 1.5 to 49.0 mV and from 0.45 to 7.26 µA/cm3, respectively. Additionally, the authors calculated and analyzed the values of Pmax, Isc, FF, Rs and Rsh. Finally, the optical properties of the thin film were studied. The total light transmission through the structure does not exceed 25% and the absorption coefficient below 600 nm is in the range 2 × 104–2 × 105 cm−1. The maximum reflectance value is observed in the UV-visible region and does not exceed 42%. The extinction coefficient varies between 0.1 and 0.9 depending on the wavelength and sample. The refractive index at 400 nm depends on the sample and is in the range of 1.7 to 4.5. The obtained values of the optical band gap for the investigated samples are 1.02 eV, 1.25 eV, 1.26 eV and 1.28 eV.

Self-powered photodetectors based on stacked WSe2/graphene/SnS2 p-g-n heterostructures

The insertion of a graphene interlayer between van der Waals (vdW) materials could suppress the interlayer recombination to improve interface quality and facilitate charge transport. However, its effect on photovoltaic-mode detectors has rarely been explored. Here, self-powered photodetectors based on WSe 2 /graphene/SnS 2 vdW heterojunctions were assembled and the impact of adding graphene interlayer on its performance was investigated. The p-g-n heterostructure exhibits a photovoltaic characteristic, V OC = 0.13 V and I SC = 0.12 nA under illumination of 2.98 mW/cm 2 @405 nm, lower than that of a control (WSe 2 /SnS 2 ) counterpart ( V OC = 0.19 V and I SC = 1.15 nA). Yet an FF value up to 48.16 % was obtained under an irradiation power density of 0.332 mW/cm 2 @405 nm, which is visibly higher than that of bare WSe 2 /SnS 2 vdW heterostructure. The insertion of graphene interlayer is deemed to reduce the charge traps between vdW materials that are caused by the large concentration difference of majority carriers. However, in case of vdW heterostructure, the subsequently increased leakage current makes the junction less ideal. Thereby interface engineering methods should be used with caution to tune vdW heterostructures on the nanoscale. The WSe 2 /graphene/SnS 2 p-g-n heterostructure offers a photovoltaic characteristic, V OC = 0.13 V and I SC = 0.12 nA under an illumination of 405 nm. An FF value up to 48.16 % was obtained at 0.332 mW/cm 2 @405 nm, which is slightly higher than that of bare WSe 2 /SnS 2 vdW heterostructure.The addition of graphene interlayer between WSe 2 and SnS 2 . • The WSe 2 /graphene/SnS 2 heterostructure offers a photovoltaic characteristic, V OC = 0.13 V and I SC = 0.12 nA @405 nm. • An FF value up to 48.16 % was obtained at 0.332 mW/cm 2 @405 nm), w. • The addition of graphene interlayer between WSe 2 and SnS 2 makes the junction less ideal.

Efisiensi Counter Electrode Dengan Pengurangan Pemakaian Platina Menggunakan Komposit Bahan Ramah Lingkungan Grafin Dan Carbon Nanotubes Untuk Aplikasi Dye Sensitized Solar Cells

&lt;p&gt;&lt;span lang="EN-AU"&gt;Dye sensitized solar cells (DSSCs) are the most popular solar cells in the third generation. DSSCs have been widely developed as an alternative to silicon-based solar cells because of its easy manufacturing process, high efficiency, easy production costs, and environmental friendliness. Graphene and carbon nanotubes (CNTs) are promising materials to reduce the use of platinum (Pt) in counter electrode (CE) due to their excellent properties, such as thermal, electrical conductivity, and high surface area. One of the derivatives of graphene that is often used is reduced graphene oxide (rGO) which is produced from GO solution by a reduction process. GO was synthesized in an electrolyte containing surfactant by the electrochemical exfoliation method. The specially prepared sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-silphonate (TC14) surfactant was used in GO synthesis. The CE thin film of TC14-rGO/CNTs/Pt hybrid shows the highest efficiency values (0.0594%) with Jsc, Voc, and FF of 0.176 mA/cm2, 0.622 V, and 0.464, respectively. This was believed due to the conjugated network in CNTs acts as a connecting cable between the TC14-rGO layers and as a vacancy filler, the high electrical conductivity value and the larger surface area also cause faster electron movement, making these properties important in DSSC performance. The FF value which is also the highest in the TC14-rGO/CNTs/Pt hybrid samples as CE is also influenced by its structure. The high surface area of CNTs and TC14-rGO in the TC14-rGO/CNTs/Pt hybrid samples exhibited important properties for generating dye after electron injection and led to a faster route of electron regulation during DSSCs processing. These findings indicate that Pt composited with environmentally friendly and inexpensive materials such as T14-rGO and CNTs can improve CE performance in DSSCs applications. Based on this, this research can be used as a basis for further research on the fabrication of carbon-based CE&lt;/span&gt;&lt;/p&gt;