Short-circuit Current Density Research Articles

In-Depth Analysis on the Fabry-Perot Effect of Cs2AgBiBr6 Double Perovskite-Based Solar Cells via Optical Path Length Modulation

Herein, the Fabry-Perot (F-P) interference of cesium silver bismuth bromide (Cs2AgBiBr6) double perovskite solar cells has been analyzed by modulating the optical path length of each layer step by step using the finite-difference time-domain (FDTD) method. The study was performed pass through three main steps. In step 1, for the fluorine-doped tin oxide (FTO)/Cs2AgBiBr6 double perovskite/gold (Au) architecture, we increased the absorption layer thickness from 150 to 600 nm at intervals of 150 nm and then predicted the optical performance including the absorption and reflection. In step 2, titanium dioxide (TiO2) layer was added between FTO electrode and Cs2AgBiBr6 double perovskite and then scaled from 20 to 200 nm at intervals of 20 nm. In the analysis process, short-circuit current density (Jsc) repeatedly fell and rose as the TiO2 layer thickness increased, and when TiO2 layer thickness is 100 nm, Jsc showed the highest value of 13.91 mA/cm2. In step 3, by applying a spiro-OMeTAD layer between the Cs2AgBiBr6 double perovskite absorption layer and Au electrode, the Jsc showed a continuous increase with slight decrease as the spiro-OMeTAD layer thickness increased from 110 to 200 nm, and when the spiro-OMeTAD layer thickness was 200 nm, Jscwas calculated as 14.57 mA/cm2, which is the highest value in the range. In the case of the optimal condition of full structure device, the Fabry-Perot resonance peaks were discovered at 477, 520, 572, 659, and 778 nm five wavelength regions, and the influence of the Fabry-Perot resonance on the generation rate inside the absorption layer on the 520, 572, and 659 nm monochromatic wavelength light was analyzed according to the position in the device. Our study approaches the Cs2AgBiBr6 double perovskite solar cell from an F-P cavity perspective and shows the light trapping phenomenon of the device according to the optical path length modulation.

Tailoring the Position of Ester Group on N-Alkyl Chains of Benzotriazole-based Small Molecule Acceptors for High-Performance Organic Solar Cells.

Side chain engineering plays a vital role in exploring high-performance small molecule acceptors (SMAs) for organic solar cells (OSCs). In this work, we designed and synthesized a series of A-DA'D-A type SMAs by introducing different N-substituted alkyl and ester alkyl side chains on benzotriazole (BZ) central unit and aimed to investigate the effect of different ester substitution positions on photovoltaic performances. All the new SMAs with ester groups exhibit lower the lowest unoccupied molecular orbital (LUMO) energy levels and more blue-shifted absorption, but relatively higher absorption coefficients than alkyl chain counterpart. After blending with the donor PM6, the ester side chain-based devices demonstrate enhanced charge mobility, reduced amorphous intermixing domain size and long-lived charge transfer state compared to the alkyl chain counterpart, which are beneficial to achieve higher short-circuit current density (Jsc ) and fill factor (FF), simultaneously. Thereinto, the PM6 : BZ-E31 based device achieves a higher power conversion efficiency (PCE) of 18.33 %, which is the highest PCE among the OSCs based on the SMAs with BZ-core. Our work demonstrated the strategy of ester substituted side chain is a feasible and effective approach to develop more efficient SMAs for OSCs.

TuningHole Transport Properties and Perovskite Crystallization via Pyridine-Based Molecules for Quasi-2D Perovskite Solar Cells.

Quasi-2D perovskites show great potential as photovoltaic devices with superior stability, but the power conversion efficiency (PCE) is limited by poor carrier transport. Here, it is simultaneously affected the hole transport layer (HTL) and the perovskite layer by incorporating pyridine-based materials into poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) to address the key problem above in 2D perovskites. With this approach, the enhanced optoelectronic performance of the novel PEDOT:PSS is due to electron transfer between the additives and PEDOT or PSS, as well as a dissociation between PEDOT and PSS based on experimental and theoretical studies, which facilitates the charge extraction and transfer. Concurrently, in-situ X-ray scattering studies reveal that the introduction of pyridine-based molecules alters the transformation process of the perovskite intermediate phase, which leads to a preferred orientation and ordered distribution caused by the Pb─N chemical bridge, achieving efficient charge transport. As a result, the pyridine-treated devices achieve an increased short-circuit current density (Jsc ) and PCE of over 17%.

Cu-Doped Sb2Se3 Thin-Film Solar Cells Based on Hybrid Pulsed Electron Deposition/Radio Frequency Magnetron Sputtering Growth Techniques

Cu-Doped Sb2Se3 Thin-Film Solar Cells Based on Hybrid Pulsed Electron Deposition/Radio Frequency Magnetron Sputtering Growth Techniques

1 MeV electron irradiation effect and damage mechanism analysis of flexible GaInP/GaAs/InGaAs solar cells

In this study, the degradation behavior of flexible GaInP/GaAs/InGaAs (IMM3J) solar cells and their metamorphic subcells under 1 MeV electron irradiation was investigated. The remaining factors such as short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power (Pmax) were 95.62, 85.52, and 79.73%, respectively, at an irradiation fluence of 2 × 1015 e/cm2. The spectral responses of the InGaAs and GaAs subcells degraded significantly, and the InGaAs subcell experienced greater degradation than the GaAs subcell after irradiation. In addition, the current-limiting unit was switched from GaInP to InGaAs after irradiation. Defect analysis by deep-level transient spectroscopy (DLTS) revealed that with increasing irradiation fluence, the defects that had the greatest impact on the performance of GaAs subcells were EV + 0.36 and EV + 0.42 eV. For InGaAs subcells, the defects that had the greatest impact on the performance were EV + 0.29 and EV + 0.24 eV. The decrease in the minority carrier lifetime is the main reason for the decrease in the electrical performance of solar cells, and the variation in the effective minority carrier lifetime (τeff) in the subcells with the irradiation fluence was calculated based on the DLTS results. At a fluence of 2 × 1015 e/cm2, the τeff of the GaAs and InGaAs subcells decreased from 2.93 × 10−10 and 9.10 × 10−10 s to 1.56 × 10−11 and 1.60 × 10−12 s, respectively. These results provide a reference for predicting the degradation of short-circuit current and open-circuit voltage of flexible IMM3J.

Surface Modification of Silicon Nanowires with Siloxane Molecules for High-Performance Hydrovoltaic Devices.

Hydrovoltaic devices (HDs) based on silicon nanowires (SiNWs) have attracted significant attention due to their potential of high output power and good compatibility with Si-based photovoltaic devices for integrated power systems. However, it remains a major challenge to further improve the output performance of SiNW HDs for practical applications. Here, a new strategy to modify the surface of SiNWs with siloxane molecules is proposed to improve the output performance of the SiNW HDs. After modification, both the open-circuit voltage (Voc) and short-circuit current density (Jsc) of n-type SiNW HDs can be improved by approximately 30%, while the output power density can be greatly increased by over 200%. With siloxane modification, Si-OH groups on the surface of typical SiNWs are replaced by Si-O-Si chemical bonds that have a weaker electron-withdrawing capability. More free electrons in n-type SiNWs are liberated from surface bound states and participate in directed flow induced by water evaporation, thereby improving the output performance of HDs. The improved performance is significant for system integration applications as it reduces the number of required devices. Three siloxane-modified SiNW HDs in series are able to drive a 2 V light-emitting diode (LED), whereas four unmodified devices in series are initially needed for the same task. This work provides a simple yet effective strategy for surface modification to improve the output performance of SiNW HDs. Further research into the effect of different surface modifications on the performance of SiNW HDs will greatly promote their performance enhancement and practical applications.

Experimental and theoretical study of improved mesoporous titanium dioxide perovskite solar cell: The impact of modification with graphene oxide

The present study serves experimental and theoretical analyses in developing a hybrid advanced structure as a photolysis, which is based on electrospun Graphene Oxide-titanium dioxide (GO-TiO2) nanofibers as an electron transfer material (ETMs) functionalized for perovskite solar cell (PVSCs) with GO. The prepared ETMs were utilized for the synthesis of mixed-cation (FAPbI3)0.8(MAPbBr3)0.2. The effect of GO on TiO2 and their chemical structure, electronic and morphological characteristic were investigated and discussed. The elaborated device, namely ITO/Bl-TiO2/3 wt% GO-TiO2/(FAPbI3)0.8(MAPbBr3)0.2/spiro-MeTAD/Pt, displayed 20.14% disposition and conversion solar energy with fill factor (FF) of 1.176%, short circuit current density (Jsc) of 20.56 mA/cm2 and open circuit voltage (VOC) 0.912 V. The obtained efficiency is higher than titanium oxide (18.42%) and other prepared GO-TiO2 composite nanofibers based ETMs. The developed materials and device would facilitate elaboration of advanced functional materials and devices for energy storage applications.

Modeling and enhancement of double perovskite solar cell using WO3 as electron transporting material and SrCu2O2 as hole transporting material

There is a growing necessity to develop renewable energy with cost-effective materials. In this work, a double perovskite-based solar cell design has been proposed. The proposed design is numerically simulated, and investigation of solar cell parameters has been carried out using SCAPS-1D simulation software. (FA)2BiCuI6 is an organic–inorganic double perovskite material employed as an absorber layer. SrCu2O2 is used as hole transporting material and WO3 is used as electron transporting material in proposed device model FTO/WO3/(FA)2BiCuI6/SrCu2O2/W. SrCu2O2 absorbs lower light due to its wide bandgap and provides better hole transport capability which reduces the recombination. WO3 has tunable bandgap and absorb light in visible spectrum and offer good conductivity and thus this combination improve the power conversion efficiency. The analysis and optimization of the various parameters of absorber layer such as thickness, shallow acceptor density, and operating temperature are done. At 500 nm absorber thickness for shallow acceptor density of 1.0 × 1018 cm−3 and 300 K operating temperature, the optimized results have been observed. The photo-voltaic parameters: open circuit voltage 1.04 V, short circuit current density 25.97 mA/cm2, fill factor 88.23 % and power conversion efficiency of the device 23.64 % are observed. The proposed configuration is a promising candidate for efficient, low-cost double perovskites-based solar cells.

Fabrication of (Ge0.42Sn0.58)S Thin Films via Co-Evaporation and Their Solar Cell Applications.

In this study, as a novel approach to thin-film solar cells based on tin sulfide, an environmentally friendly material, we attempted to fabricate (Ge, Sn)S thin films for application in multi-junction solar cells. A (Ge0.42 Sn0.58)S thin film was prepared via co-evaporation. The (Ge0.42 Sn0.58)S thin film formed a (Ge, Sn)S solid solution, as confirmed by X-ray diffraction (XRD) and Raman spectroscopy analyses. The open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and power conversion efficiency (PCE) of (Ge0.42 Sn0.58)S thin-film solar cells were 0.29 V, 6.92 mA/cm2, 0.34, and 0.67%, respectively; moreover, the device showed a band gap of 1.42-1.52 eV. We showed that solar cells can be realized even in a composition range with a relatively higher Ge concentration than the (Ge, Sn)S solar cells reported to date. This result enhances the feasibility of multi-junction SnS-system thin-film solar cells.

Efficient flexible dye-sensitized solar cells from rear illumination based on different morphologies of titanium dioxide photoanode

The TiO2 with nanoparticles (NPs), nanowires (NWs), nanorods (NRs) and nanotubes (NTs) structures were prepared by using a in-situ hydrothermal technique, and then proposed as a photoanode for flexible dye-sensitized solar cell (FDSSC). The influences of the morphology of TiO2 on the photovoltaic performances of FDSSCs were investigated. Under rear illumination of 100 mW·cm−2, the power conversion efficiencies of FDSSCs achieved 6.96%, 7.36%, 7.65%, and 7.83% with the TiO2 photoanodes of NPs, NWs, NRs, and NTs and PEDOT counter electrode. The FDSSCs based on TiO2 NRs and NTs photoanodes have higher short circuit current densities and power conversion efficiencies than that of the others. The enhanced power conversion efficiency is responsible for their nanotubes and rod-shaped ordered structures, which are more beneficial to transmission of electron and hole in semiconductor compared to the TiO2 nanoparticles and nanowires disordered structure.

Comparative study by simulation betweentwo structures CdS/CZTS and ZnS/CZTS via SCAPS-1D software

This comparative numerical simulation study investigates the electrical characteristics of two heterojunction thin-film solar cells based on Kësterites Copper Zinc Tin Sulfide. The study compared two solar cells with different structures, Zinc Oxide ZnO/Cadmium Sulfide CdS/Kësterites CZTS/Molybdenum Mo and Zinc Oxide ZnO/Zinc Sulfide ZnS/Kësterites CZTS/Molybdenum Mo, to determine which is more efficient in achieving maximum photovoltaic efficiency. The results showed that the ZnO/ZnS/CZTS/Mo solar cell is the better option, outperforming the CdS/CZTS/Mo solar cell in terms of short-circuit current density Jsc, open-circuit voltage Voc, form factor FF, and photovoltaic efficiency η. The study also investigated the effect of doping and layer thickness of CZTS and ZnS on photovoltaic parameters. The optimized ZnS/CZTS solar cell achieved an efficiency of 16.29% for ZnS and CZTS layer thicknesses of 0.02µm and 4μm, respectively, and doping concentrations of 1018 and 1016cm-3 , respectively. Overall, this study provides valuable insights for designing more efficient solar cells and optimizing their photovoltaic efficiency using Kësterites CZTS, CdS, and ZnS materials.

Regulating SnZn defects and optimizing bandgap in the Cu2ZnSn(S,Se)4 absorption layer by Ge gradient doping for efficient kesterite solar cells

In recent years, the primary reasons for low efficiency Cu2ZnSn(S,Se)4 (CZTSSe) solar cells have been attributed to SnZn defects and related defect clusters, as well as the balance of absorption layer bandgap for short-circuit current density (Jsc) and open-circuit voltage (Voc). Ge gradient has been theoretically proven to be an effective strategy to change traditional flat bandgap structure and suppress SnZn defects and related defect clusters for improving the device performance of CZTSSe solar cells. However, the potential of Ge gradient has not been fully verified. In this work, Ge doping effectively reduces the formation of SnZn defects and [2CuZn + SnZn] defect clusters in the CZTSSe absorption layer. In addition, it can be found that the construction of the V-type bandgap is the best solution for balancing between Voc and Jsc. By using the bandgap grading strategy, the disparity between the recombination barrier of the junction and the optical bandgap's minimum value is widened, thereby obtaining a large Voc. The V-type doped device has the highest efficiency when Voc is 0.45 V, which can reach 8.03%. This Ge graded substitution method provides an alternative absorption layer structure for improving Voc and the preparation of future high-efficiency kesterite photovoltaic devices.

Significant Role of Fe3+ Sites on the Activation Energy Barrier at Electrode Interface in SnO2-Fe2O3 Composite Based Hydroelectric Cell

Hydroelectric cell (HEC) is a green energy device known for its potential to replace solar cell and fuel cell in coming decades. Among number of materials explored, tin oxide-based cells have shown a huge potential to deliver high current densities with high activation losses. In this study, to overcome the activation loss, tin oxide-hematite composite based HEC power characteristics has been analysed. The composite cell delivered a short circuit current density of Isc~7.0 mA/cm2 and peak power of Pden ~ 26.9 mW. More structural defects were found to nucleate in the composite compared to pure tin oxide confirmed by X-ray diffraction (XRD) and Raman spectroscopy. Scanning electron microscopy (SEM) revealed the high surface area and porous microstructure of the composite. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of chemi-dissociated and physisorbed water molecules on the composite surface. The composite based hydroelectric cell displayed low activation losses compared to the bare SnO2 HEC observed by the V-I characteristics. A significant role of Fe3+ cations has been found crucial for the reduction in activation energy barrier in the composite based HEC.

Analyzing the synergistic effect of Ag and Ge co-incorporation on Cu2ZnSnSe4 thin-film solar cells

At present, the large number of inherent CuZn anti-site defects and harmful [2CuZn + SnZn] defect clusters in the CZTSe film layer limit the further progress of device efficiency. In this paper, Ag and Ge double cations were introduced into the CZTSe film layer, and (CuAg)2ZnSnGeSe4 (CAZTGSe) films were synthesized successfully by the sol-gel method to cut down the above defects and defect clusters to obtain high-efficiency devices. The influences of double cation substitution on CZTSe by partly replacing Cu with Ag and Sn with Ge were developed. The role of Ag, Ge, and Ag + Ge substitution was researched by X-ray diffraction, scanning electron microscopy, current density-voltage (J-V), and external quantum efficiency measurements. By incorporating 5% Ag and 20% Ge double cations into the CZTSe film, the device demonstrated the highest efficiency of 10.12%. In addition, the open circuit voltage (VOC) of 503.57 mV, the short circuit current density (JSC) of 31.36 mA/cm2, and the fill factor (FF) of 64.1% were obtained.

Efficient Tin-Based Perovskite Solar Cell with a Cesium Acetate Pre-buried PEDOT:PSS Hole Transport Layer.

The strong Lewis acid tin halide leads to an excessively fast crystallization rate, resulting in more defects in the film and degraded device performance. In this work, a cesium acetate (CsAc) pre-buried poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer acts as nucleation points during the crystallization of tin-based perovskite, which can induce preferential orientation growth of crystals and increase the grain size to improve the quality of crystallization. The addition of CsAc not only can increase the conductivity of PEDOT:PSS but also can improve the wettability of the perovskite precursor solution to enhance the interface contact between the hole transport layer and perovskite layer. Because of the incorporation of CsAc in PEDOT:PSS, the average short-circuit current density increases from 23.80 to 27.60 mA cm-2. Furthermore, a power conversion efficiency of 10.99% is achieved for a tin-based perovskite solar cell with CsAc-doped PEDOT:PSS as the hole transport layer.

Metal complex as p-type dopant-based organic spiro-OMeTAD hole-transporting material for free-Li-TFSI perovskite solar cells.

Lithium bis(fluorosulfonyl)imide (Li-TFSI) is an efficient p-dopant that has been used to enhance the conductivity of perovskite solar cells (PSCs). However, the performance of the corresponding devices is still not satisfactory due to the impact of Li-TFSI on the fill factor and the short-circuit current density of these PSCs. Herein, a new Mn complex [(Mn(Me-tpen)(ClO4)2-)]2+ was introduced as a p-type dopant into spiro-OMeTAD and was successfully applied as a hole transport material (HTM) for PSCs. Analytical studies used for device characterization included scanning electron microscopy, UV-Vis spectroscopy, current-voltage (IV) characteristics, incident photon to current efficiency, power conversion efficiency (PCE), and electrochemical impedance spectroscopy. The UV-Vis spectra displayed oxidation in the HTM by the addition of a dopant. Moreover, the movement of electrons from the higher orbital of the spiro-OMeTAD to the dopant stimulates the generation of the hole carriers in the HTM, enhancing its conductivity with outstanding long-term stability under mild conditions in a humid (RH ∼ 30%) environment. The incorporation of the Mn complex into the composite improved the material's properties and the stability of the fabricated devices. The Mn complex as a p-type dopant for spiro-OMeTAD exhibits a perceptible PCE of 16.39% with an enhanced conductivity of 98.13%. This finding may pave a rational way for developing efficient and stable PSCs in real environments.

Intramolecular charge transfer character of D-π-A chromophores with modulating the subunits sequence of π-bridge

Two D-B-A compounds (TRD and TTRD) were designed with the different bridges (B1 and B2) consisting of T and TT moieties. They were synthesized and investigated by UV–Vis spectra, steady state emission spectra, X-ray diffraction, electrochemical measurement, the photovoltaic performances and theoretical calculation. The large Stokes shift suggested the formation of an intramolecular charge transfer (ICT) state in the excited state. TTRD based device showed high short-circuit current density (JSC) and fill factor (FF). It was essential to understanding the underlying mechanism caused by the subtle structural difference of the two spacers. The results showed that the B2 bridge extending the electron increment region has shown a significant improvement for excitation delocalization, which played a crucial role in improving effective dissociation of the ICT excitons, leading to the increase of photogenerated charge carriers.

Theoretical analysis of doping of perovskite light-absorbing layer for highly efficient perovskite solar cells

The physical properties of perovskites—the central components of perovskite solar cells (PSCs)—are crucial for photovoltaic (PV) performance. Suitable doping of perovskites can improve the electric-field distribution within them, thus enhancing their PV performance. In this study, the effects of the three doping strategies on PV performance of MAPbI3 based PSCs were explored. First, uniform acceptor doping of perovskite was performed. With increasing uniform acceptor doping concentration (NA), the open-circuit voltage (VOC) gradually increased, but the short-circuit current density (JSC) decreased. As the decline in JSC limited further PCE increase, non-uniform acceptor doping of perovskite was performed, which increased the width of the space-charge region near the MAPbI3/SnO2 interface, promoting the flow of holes from MAPbI3 to the carbon electrode. The JSC increased from 19.05 to 22.30 mA cm−2, and the power conversion efficiency (PCE) increased from 19.74 % to 22.72 % when the doping concentration curve for non-uniform acceptor doping was a line passing through 3 × 1018 and 3 × 1014. In order to further enhance the PCE, simultaneous non-uniform acceptor doping and uniform donor doping of perovskite was adopted, which further improved the JSC and fill factor (FF), and the PCE increased from 22.72 % to 23.92 % when the uniform donor doping concentration was 1 × 1018 cm−3. This work provides a strategy of doping of perovskite for highly efficient PSCs.

Amino Acid Double-Passivation-Enhanced Quantum Dot Coupling for High-Efficiency FAPbI3 Perovskite Quantum Dot Solar Cells.

Formamidinium lead triiodide (FAPbI3) perovskite quantum dot has outstanding durability, reasonable carrier lifetime, and long carrier diffusion length for a new generation of highly efficient solar cells. However, ligand engineering is a dilemma because of the highly ionized and dynamic characteristics of quantum dots. To circumvent this issue, herein, we employed a mild solution-phase ligand-exchange approach through adding short-chain amino acids that contain amino and carboxyl groups to modify quantum dots and passivate their surface defects during the purification process. As a result, the photoelectric conversion efficiency of FAPbI3 perovskite quantum dot solar cells (PQDSCs) increased from 11.23 to 12.97% with an open-circuit voltage of 1.09 V, a short-circuit current density of 16.37 mA cm-2, and a filling factor of 72.13%. Furthermore, the stability of the device modified by amino acids retains over 80% of the initial efficiency upon being exposed to 20-30% relative humidity for 240 h of aging treatment. This work may offer an innovative concept and approach for surface ligand treatment to improve the photovoltaic performance of PQDSCs toward large-scale manufacture.

Utilizing the lignocellulosic fibers from Pineapple Crown Leaves extract for enhancing TiO2 interfacial bonding in dye-sensitized solar cell photoanodes

AbstractThe crown leaves of pineapple possess a wealth of smooth and glossy silk medium-length fibers, primarily composed of cellulose and lignin, accompanied by constituents such as fats, waxes, pectin, uronic acid, anhydride, pentosan, color pigments, and inorganic substances. These fibers exhibit an anisotropic nature and are characterized by hydrogen bonding interactions, rendering them effective in conjunction with semiconductor oxide (TiO2) through their cellulosic fibrils. The dye extracted from Pineapple Crown Leaves (PCL) using ethanol was subjected to FTIR and UV–visible spectroscopy. The FTIR analysis revealed absorption peaks at 3268 cm−1 and 2922 cm−1, confirming the presence of –OH and –CH stretching attributed to the fibrils within the dye. UV–visible spectroscopy further demonstrated absorption within the visible region of the electromagnetic spectrum. Additionally, a photoluminescence study of the dye showcased emission within the visible range of the electromagnetic spectrum. Subsequently, a solar cell incorporating this dye underwent JV characterization, yielding an efficiency of 1.0034%, along with fill factor, open-circuit voltage, and short-circuit current density values of 0.40644, 0.7058 V, and 3.4906 mA/cm2, respectively. To gain deeper insights and facilitate optimization for large-scale installations, a simulation model utilizing PC1D was proposed to explore the influential parameters of the Dye-sensitized solar cell (DSSC).