Short-circuit Current Density Research Articles

Comprehensive investigation of material properties and operational parameters for enhancing performance and stability of FASnI3-based perovskite solar cells

Recent advancements in the efficiency of lead-based halide perovskite solar cells (PSCs), exceeding 25%, have raised concerns about their toxicity and suitability for mass commercialization. As a result, tin-based PSCs have emerged as attractive alternatives. Among diverse types of tin-based PSCs, organic–inorganic metal halide materials, particularly FASnI3 stands out for high efficiency, remarkable stability, low-cost, and straightforward solution-based fabrication process. In this work, we modelled the performance of FASnI3 PSCs with four different hole transporting materials (Spiro-OMeTAD, Cu2O, CuI, and CuSCN) using SCAPS-1D program. Compared to the initial structure of Ag/Spiro-OMeTAD/FASnI3/TiO2/FTO, analysis on current–voltage and quantum efficiency characteristics identified Cu2O as an ideal hole transport material. Optimizing device output involved exploring the thickness of the FASnI3 layer, defect density states, light reflection/transmission at the back and front metal contacts, effects of metal work function, and operational temperature. Maximum performance and high stability have been achieved, where an open-circuit voltage of 1.16 V, and a high short-circuit current density of 31.70 mA/cm2 were obtained. Further study on charge carriers capture cross-section demonstrated a PCE of 32.47% and FF of 88.53% at a selected capture cross-section of electrons and holes of 1022 cm2. This work aims to guide researchers for building and manufacturing perovskite solar cells that are more stable with moderate thickness, more effective, and economically feasible.

The impact of a ZnO space layer on enhancing the efficiency of P3HT: PCBM blend-based organic solar cells

The performance of Organic Solar Cells (OSCs) based on a composite photoactive of poly(3-hexylthiophene) (P3HT) and 6,6-phenylC61-butyric acid methyl ester (PCBM) as the donor and acceptor electrons, respectively, is examined in this paper through a simulation study. Optical Zinc oxide (ZnO) spacers between the active layer and the Aluminum (Al) cathode contact layer, serving as a hole transport layer (HTL), are compared to the usual configuration without a ZnO spacer in the second device construction. With and without the ZnO optical spacer, we calculate the electric field intensities and generation rates (G) for a range of incident wavelengths. Under AM 1.5 G at 100 mW cm−2 illumination and in the dark, the short-circuit current density (Jsc) is improved by up to 9.47% after adding the ZnO layer as an optical spacer. In addition, there is a gain of up to 11.42% in external quantum efficiency (EQE). Furthermore, the ZnO spacer layer device has a markedly higher incident photon-to-electron conversion efficiency (IPCE), going from 77% in the control device (without ZnO) to 90% with ZnO spacer layer. The numerical simulation results based on the finite element method (FEM) are consistent with the published experimental data.

Manipulating Alkyl Inner Side Chain of Acceptor for Efficient As-Cast Organic Solar Cells.

As-cast organic solar cells (OSCs) possess tremendous potential for low-cost commercial applications. Herein, five small-molecule acceptors (A1-A5) are designed and synthesized by selectively and elaborately extending the alkyl inner side chain flanking on the pyrrole motif to prepare efficient as-cast devices. As the extension of the alkyl chain, the absorption spectra of the films are gradually blue-shifted from A1 to A5 along with slightly uplifted lowest unoccupied molecular orbital energy levels, which is conducive for optimizing the trade-off between short-circuit current density and open-circuit voltage of the devices. Moreover, a longer alkyl chain improves compatibility between the acceptor and donor. The in situ technique clarifies that good compatibility will prolong molecular assembly time and assist in the preferential formation of the donor phase, where the acceptor precipitates in the framework formed by the donor. The corresponding film-formation dynamics facilitate the realization of favorable film morphology with a suitable fibrillar structure, molecular stacking, and vertical phase separation, resulting in an incremental fill factor from A1 to A5-based devices. Consequently, the A3-based as-cast OSCs achieve a top-ranked efficiency of 18.29%. This work proposes an ingenious strategy to manipulate intermolecular interactions and control the film-formation process for constructing high-performance as-cast devices.

Machine learning driven performance enhancement of perovskite solar cells with CNT as both hole transport layer and back contact

We propose a machine learning-based approach to enhance the performance of perovskite solar cells (PSCs) using carbon nanotubes as both hole transport layer (HTL) and back contact. Carbon-based PSCs offer low fabrication costs, long-term mechanical stability, high charge transport, and broad wavelength transparency. Our study estimates and enhances power conversion efficiency (PCE) of carbon-based PSCs through machine learning. PSC with single-walled carbon nanotube (SWCNT)-based HTL and back contact is investigated in simulations using SCAPS-1D and achieved 14.24% PCE, closely aligning with experimental data. Additionally, we explore the impact of various easily tunable fabrication parameters, such as the band gap and electron affinity of SWCNT in HTL, HTL thickness, active layer thickness, electron transport layer (ETL) thickness, HTL dopant concentration, absorber defect density, and ETL dopant concentration, on PCE. We generate a dataset of 20,480 samples to train classical and neural network-based machine learning models to predict performance parameters of PSCs, including short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF), and PCE (η). The current density vs. voltage (J-V) characteristics curve is well-fitted by the predicted JSC, VOC, and FF, as evidenced by an average root mean squared error (RMSE) of 0.03 and a goodness of fit (R2) value of 0.99. The fully connected artificial neural network performs best, with RMSE of 0.05% and R2 of 0.99998 for predicting PCE. Genetic algorithm is used to optimize PCE, yielding a maximum PCE of 20.92%. Furthermore, an analysis of feature dimension and dataset size on prediction performance guides future modeling approaches.

TiO2 nanoparticle seeds transformed into nanotubes for effective dye-sensitized solar cell application

Morphology plays a vital role in dye-sensitized solar cells (DSSCs) due to their high surface area, dye adsorption and electron transport. In this study, we have designed and fabricated titanate nanotube photoanodes by a simple one-step hydrothermal method. High-resolution transmission electron microscope (HRTEM) analysis revealed the transformation of nanoparticles to nanotube morphology. Brauner-Emmett-Teller (BET) method showed the enhanced surface area and pore diameter of nanotubes. TiO2 nanotube photoanode showed excellent energy conversion efficiency (2.38 %), short circuit current densities (Isc) (6.29 mA/cm2), and fill factors (FF) (0.63), respectively.

Investigation of Laser micro-textured triboelectric nanogenerator based self-powered vibration sensor for industry 4.0 application

Self-powered sensors detect a variety of crucial parameters for industrial processes without any external power source for Industry 4.0. It has capabilities to acquire, analyze, and make decisions on real-time data, these sensors are essential for the advancement of automated production systems and smart factories. In this regard, Triboelectric nanogenerators (TENGs) have potential to provide effective solution as self-powered vibration sensor for continuous monitoring of machine tools. Different techniques have been used to enhance the performance of TENG such as material doping, chemical etching, ion injection, etc. However, laser surface texturing is a low-cost, contact less, efficient technique which can be used for improving the response of TENG-based self-powered vibration sensors. In this context, Laser Induced Backside Texturing is a laser micro texturing approach to improve the electrical performance. It induces waviness and surface roughness, which leads to increased surface charge density and triboelectrification capabilities. In this work, laser micro texturing was performed using with 405 nm wavelength semiconductor diode laser to generate line pattern texture on the Fluorinated Ethylene Propylene (FEP). Laser textures TENG (LT-TENG) was developed with laser textured FEP as tribonegative material and pristine Aluminium as tribopositive material, the open-circuit voltage, short-circuit current and power density achieved 23 %, 41 %, and 47 % enhancement respectively, generating 794 V, 44 µA, and 2371.6 µW/cm2. This increase in output leads to an increased sensitivity of the sensor. When mounted on the machines, LT-TENG was able to detect their working state, vibration frequency, and harmonics i.e. 46, 92, 184 Hz for the vacuum pump and 140, 280, 410 Hz for the heat gun. These detected vibration frequencies, and their harmonics were similar to the frequencies detected by the commercial accelerometer (CTC AC115), confirming potential use of LT-TENG as a low-frequency vibration sensor. The developed LT-TENGs was integrated with the Internet of Things (IoT) supported microcontroller, which collects real-time data for continuous monitoring and analysis for machine health monitoring in smart devices.

Increased performance of A-DA’D-A type acceptor based organic solar cell using a thermally coevaporated cathode-modifying blend layer

The blend thin films of bathocuproine and fullerene (BCP:C60) have been thermally coevaporated to modify the active layer/cathode interfaces in organic solar cells. The BCP forms a much smaller-barrier contact with cathode than the C60. Because the surface zone of active layer is polymer donor-rich and small-molecular acceptor-deficient, C60 molecules make insufficiently large contact area with electron acceptor, leading to inefficient electron extraction. However, BCP molecules penetrate the surface of active layer, due to the smaller molecular size of BCP than that of C60, and likely form sufficiently large contact area with electron acceptor thereby to enable efficient electron extraction. Compared to conventional 10 nm BCP, 10 nm BCP:C60 (1:1 in mass ratio) enables higher efficiency based on the active layer using A-DA’D-A type acceptor, mostly because C60 constituent dissociates some excitons photogenerated in the polymer donor of surface zone and thereby increases short-circuit current density. The current research provides novel insights into the development of cathode-modifying layers for organic solar cells.

Manipulating the Crystallization of Tin Halide Perovskites for Efficient Moisture-to-Electricity Conversion.

Manipulating the crystallization of perovskite in thin films is essential for the fabrication of any thin-film-based devices. Fabricating tin-based perovskite films from solution poses difficulties because tin tends to crystallize faster than the commonly used lead perovskite. To achieve optimal device performance in solar cells, the preferred method involves depositing tin perovskite under inert conditions using dimethyl sulfoxide (DMSO), which effectively retards the formation of the tin-bromine network, which is crucial for perovskite assembly. We found that under ambient conditions, a DMSO-based tin perovskite salt solution resulted in the formation of a two-phase system, SnBr4(DMSO)2 and MABr, whereas a dimethylformamide-based solution resulted in the formation of vacancy-ordered double perovskite MA2SnBr6. Humidity is known to solvate MABr to form the solvated ions, and so we used the two-phase system for the application in moisture to electricity conversion. The importance of the presence of the scaffold can be seen with the negligible power output from the vacancy-ordered double perovskite obtained with MA2SnBr6. We have fabricated a device with two-phase system that can generate an open-circuit potential of 520 mV and a short-circuit current density of 30.625 μA/cm2 at 85% RH. Also, the device charges a 10 μF capacitor from 150 mV at 51% RH to 500 mV at 85% RH in 6 s at a rate of 52.5 mV/s. Moreover, the output can be scaled by connecting devices in series and parallel configurations. A 527 nm green LED was powered by connecting five devices in series at 75% RH. This indicates a potential for utilizing these moisture-to-electricity conversion devices in powering low-energy requirement devices.

Anion and Cation Co-Doping of NiO for Transparent Photovoltaics and Smart Window Applications

Materials engineering based on metal oxides for manipulating the solar spectrum and producing solar energy have been under intense investigation over the last years. In this work, we present NiO thin films double doped with niobium (Nb) and nitrogen (N) as cation and anion dopants (NiO:(Nb,N)) to be used as p-type layers in all oxide transparent solar cells. The films were grown by sputtering a composite Ni-Nb target on room-temperature substrates in plasma containing 50% Ar, 25% O2, and 25% N2gases. The existence of Nb and N dopants in the NiO structure was confirmed by the Energy Dispersive X-Ray and X-Ray Photoelectron Spectroscopy techniques. The nominally undoped NiO film, which was deposited by sputtering a Ni target and used as the reference film, was oxygen-rich, single-phase cubic NiO, having a visible transmittance of less than 20%. Upon double doping with Nb and N the visible transmittance of NiO:(Nb,N) film increased to 60%, which was further improved after thermal treatment to around 85%. The respective values of the direct band gap in the undoped and double-doped films were 3.28 eV and 3.73 eV just after deposition, and 3.67 eV and 3.76 eV after thermal treatment. The changes in the properties of the films such as structural disorder, direct and indirect energy band gaps, Urbach tail states, and resistivity were correlated with the incorporation of Nb and N in their structure. The thermally treated NiO:(Nb,N) film was used to form a diode with a spin-coated two-layer, mesoporous on top of a compact, TiO2 film. The NiO:(Nb,N)/TiO2heterojunction exhibited visible transparency of around 80%, showed rectifying characteristics and the diode’s parameters were deduced using the I-V method. The diode revealed photovoltaic behavior upon illumination with UV light exhibiting a short circuit current density of 0.2 mA/cm2 and open-circuit voltage of 500 mV. Improvements of the output characteristics of the NiO:(Nb,N)/TiO2 UV-photovoltaic by proper engineering of the individual layers and device processing procedures are addressed. Transparent NiO:(Nb,N) films can be potential candidates in all-oxide ultraviolet photovoltaics for tandem solar cells, smart windows, and other optoelectronic devices.

PEDOT: PSS/PC71BM with various Rubrene doping levels for the production of Organic/Inorganic hybrid silicon solar cells with enhanced yield efficiency

Polymer-based solar cells (PSCs) have garnered considerable interest due to their potential advantages over traditional organic/inorganic hybrid silicon solar cells, including reduced material and production costs, compact substrates, and lightweight finished photovoltaic cells. To explore this further, we examined the impact of Rubrene in the PEDOT: PC71BM hole transport layer within the bulk Heterojunction framework of solution-processable polymer photovoltaic cells. Cells were created by combining PEDOT: PSS and PC71BM, incorporating Rubrene at 6, 9, 12, and 15 wt% ratios. The device structure comprised Si/PEDOT: PSS/PC71BM: Rubrene: DMSO/Ag, with Ag serving as a cathode fabricated in a low-pressure chamber. Notably, employing a 6 wt% Rubrene solution yielded improved short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) of 13.97 mA.cm−2, 514.80 mV, 40.97, and 2.948 %, respectively. These results demonstrate enhanced PCE with the addition of Rubrene compared to prior studies utilizing an active Rubrene surface.

Highly Efficient Organic Solar Cells with the Highly Crystalline Third Component as a Morphology Regulator.

The morphology of the active layer is crucial for highly efficient organic solar cells (OSCs), which can be regulated by selecting a rational third component. In this work, the highly crystalline nonfullerene acceptor BTP-eC9 is selected as the morphology regulator in OSCs with PM6:BTP-BO-4Cl as the main system. The addition of BTP-eC9 can prolong the nucleation and crystallization progress of acceptor and donor molecules, thereby enhancing the order of molecular arrangement. Meanwhile, the nucleation and crystallization time of the donor is earlier than that of the acceptors after introducing BTP-eC9, which is beneficial for obtaining a better vertical structural phase separation. The exciton dissociation, charge transport, and charge collection are promoted effectively by the optimized morphology of the active layer, which improves the short-circuit current density and filling factor. After introducing BTP-eC9, the power conversion efficiencies (PCEs) of the ternary OSCs are improved from 17.31% to 18.15%. The PCE is further improved to 18.39% by introducing gold nanopyramid (Au NBPs) into the hole transport layer to improve photon utilization efficiency. This work indicates that the morphology can be optimized by selecting a highly crystalline third component to regulate the nucleation and crystallization progress of the acceptor and donor molecules.

Efficiency enhancement of novel ITO/ZnSe/CNTs thin film solar cell

This study presents a novel photovoltaic cell design utilizing a layered structure of Indium Tin Oxide (ITO), Zinc Selenide (ZnSe), and Carbon Nanotubes (CNTs) for enhanced solar energy conversion. We employed the Solar Cell Capacity Simulator (SCAPS-1D) to model and optimize the device under AM 1.5 spectrum conditions. Our simulations systematically investigated the influence of key parameters including layer thicknesses, doping concentrations, temperature, back contact work function, and parasitic resistances on cell performance. The optimized structure demonstrated a theoretical power conversion efficiency of 29.91%, with an open-circuit voltage (Voc) of 799 mV, a short-circuit current density (Jsc) of 43.49 mA/cm², and a fill factor (FF) of 86.02%. These promising results are attributed to the synergistic combination of CNTs' broad spectral absorption, ZnSe's effective charge separation, and optimized layer properties. We found that the CNT absorber layer's doping concentration significantly impacted cell performance, with an optimal value of 10¹⁷ cm⁻³. The ZnSe buffer layer thickness showed minimal effect on efficiency within the studied range. Temperature increases from 300 K to 400 K led to a significant efficiency drop from 33.97% to 24.65%, primarily due to Voc reduction. While these results represent idealized conditions and upper theoretical limits, they provide valuable insights for the potential of CNT-based solar cells. This study offers a roadmap for future experimental work in high-efficiency thin-film photovoltaics, highlighting the promise of novel material combinations and the importance of device architecture optimization.

SCAPS 1D based study of hole and electron transfer layers to improve MoS2–ZrS2 solar cell efficiency

In the realm of photovoltaic applications, scientists and technocrats are striving to maximize the solar cell input photon energy conversion to electricity. However, achieving optimal cell efficiency requires significant time and energy investment for each variation and optimization. To overcome this issue authors simulated and studied the fabricated cell for optimizing conditions, which can save time and efforts for the relatively better outcomes. The family of transition metal chalcogenides holds promise as a material that yield improved outcomes in optoelectronic applications, particularly in photovoltaics. These materials are employed in experimental investigations aimed at enhancing solar cell parameters, resulting in the development of the FTO/ZnO/ZrS2/MoS2/CuO/Au composite cell. Numerical simulations utilizing SCAPS-1D software is conducted, focusing on the significance of CuO as a hole transport layer (HTL), and ZnO as an electron transport layer (ETL). The investigation examines into the impact of various factors, including thickness, bandgap, and carrier densities for both HTL and ETL, on fundamental solar cell parameters. The study indicates that device parameters are influenced by factors such as recombination rate, photogenerated current, charge carrier length, and built-in-voltage. Optimized parameters for HTL, including thickness, bandgap, and carrier concentration, are determined to be 0⋅35 μm, 1⋅2 eV, and 1⋅0 × 1020 cm–3, respectively. For ETL, the optimized parameters are found to be 0⋅05 μm, 3⋅1 eV, and 1⋅0 × 1018 cm–3, respectively. With these optimized parameters, the efficiency of the solar cell reached 20⋅64%, accompanied by open circuit voltage, short circuit current density, and fill factor values of 0.836 V, 36.021 mA⋅cm–2, and 68⋅54%, respectively. The simulated results indicate that addition of two extra layers and the use of efficient binary materials in heterojunction formation can effectively enhance device parameters, offering advantages such as low-cost and large-scale fabrication.

Light management in hole transport layer-free perovskite solar cell by SPP and LSPR

In recent years, light management based on localized surface plasmon resonance (LSPR) effects in perovskite solar cells (PSCs) has received significant attention. However, the use of surface plasmon polariton (SPP) excitations in PSCs has been less studied. Meanwhile, hole transport layer-free perovskite solar cells (HTL-free PSCs) have garnered interest due to their lower cost. In this study, we improve light absorption in HTL-free PSCs by simultaneously utilizing LSPR and SPP effects. Au nanotriangles are employed on the surface of the back electrode to excite SPPs. The thickness of the perovskite layer is varied from 100 nm to 400 nm. The optimal periodicity and dimensions of the triangular nanoparticles are determined for each perovskite layer thickness. In the optimal structures with perovskite layer thicknesses of 100 nm, 200 nm, 300 nm, and 400 nm, absorption enhancements of 25%, 12.4%, 13%, and 4.3% are achieved, respectively. The interaction of light with SPP and LSP modes leads to improved solar cell performance. Furthermore, the short circuit current density (JSC) in structures with layer thicknesses of 100 nm and 200 nm increased from 16.7 mA cm−2 to 20.71 mA cm−2 and from 19.8 mA cm−2 to 21.86 mA cm−2, respectively. Other photovoltaic characteristics of the solar cell were obtained through optical-electrical numerical analysis. For the improved solar cell with a perovskite thickness of 100 nm, the values of open circuit voltage, efficiency, and fill factor were 0.847 V, 0.81, and 14.24%, respectively, representing increases of 1.1%, 2.4%, and 28.7% compared to the bare device. Additionally, in the solar cell with a thickness of 200 nm, an efficiency of 17.03% was achieved, showing a 12.5% improvement compared to the bare structure. Our research results facilitate the design of high-performance, ultra-thin, semi-transparent solar cells.

Mechanically robust and self-cleaning antireflective coatings for photovoltaic modules

As the conversion efficiency of solar cells approaches its theoretical upper limit, the importance of photon management in enhancing photovoltaic modules performance becomes paramount. One promising approach involves the application of antireflective coatings to the surface of the photovoltaic glass to improve its transmittance. However, balancing mechanical durability, self-cleaning characteristics, and optical performance for photovoltaic applications remains challenging. This study focuses on synthesizing a composite coating through the sol-gel method, aiming to achieve high optical transmittance and superior mechanical properties. Hollow silica nanoparticles (HSN) are employed to achieve a reduced refractive index, while a composite sol of zirconium dioxide (ZrO2) and titania (TiO2) is utilized to enhance mechanical strength and hydrophilicity. The prepared composite coatings demonstrate notable improvements, with the photovoltaic transmittance (TPV) increasing from 88.31 % to 94.03 % in the 300–1100 nm wavelength range, with peak transmittance reaching 98.01 %. Additionally, the coatings exhibited a pencil hardness rating of 3H alongside exceptional abrasion resistance, affirming their potential for enduring practical deployment. When compared to uncoated glass, modules integrated with these composite coatings showed a significant increase in short-circuit current density (JSC) by 1.28 mA cm-2 and in photoelectric conversion efficiency (PCE) by 0.70 %. These results highlight the composite coatings' capacity to enhance the conversion efficiency of photovoltaic modules significantly. By attempting to prepare anti reflective coatings with high mechanical strength and self-cleaning properties, this study is expected to make a valuable contribution to the advancement of sustainable and durable solar cell technology.

High-efficiency ultra-thin GaAs solar cells based on ITO/Ag/ITO transparent electrodes and photonic crystals

Ultrathin photovoltaic technology has great potential to improve efficiency and reduce costs. However, achieving optical thickness requires an effective light capture strategy. In this study, for GaAs thin film solar cells with an active layer thickness of 500 nm, we adopt a combination strategy of front-end ITO/Ag/ITO transparent electrodes and back-end photonic crystals (PC). By employing the finite difference time domain (FDTD) simulation, we verify that ITO/Ag/ITO transparent electrodes and AlGaAs PC can effectively enhance the light-harvesting capacity of cells. The proposed cell structure has a spectral absorption rate (SAR) of 0.9781 in the visible wavelength range. To further optimize the photovoltaic performance parameters, we optimize the doping concentration of the pn junction in the cell. Finally, the short circuit current density Jsc, open circuit voltage Voc, fill factor (FF) and photoelectric conversion efficiency (PCE) of GaAs thin film solar cells are successfully increased to 31.10mAcm−2, 1.28V, 88.18% and 35.12%, respectively. This provides crucial experimental validation and theoretical guidance for advancing ultra-thin photovoltaic technology.

An investigation on the impact of temperature variation over the performance of formamidinium tin iodide perovskite solar cell using SCAPS simulation

The primary goals of this project are to analyze the structure and assess the photovoltaic performance of n-i-p structured formamidinium tin iodide (FASnI3) perovskite solar cells at different operating temperatures to inspect the impact of operating temperature on device performance using a Solar Cell Capacitance Simulator (SCAPS). The simulated device structure is Au/spiro-OMeTAD/P3HT/FASnI3/PCBM/TiO2/FTO, whereas spiro-OMeTAD and TiO2 serve as the hole transport layer and electron transport layer, respectively. SCAPS simulation has been performed at 200, 300, 400, 500, and 600 K operating temperatures, and corresponding current density vs voltage (J–V) characteristics have been studied in addition to the photovoltaic metrics, such as open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), and power conversion efficiency (PCE). The thickness fluctuation and doping concentration variation of the absorber layer and the electron affinity variation and thickness variation of the Hole Transport Layer (HTL) and Electron Transport Layer (ETL) under temperature variation were also examined analytically. It has been found that there is an inverse relationship between temperature and power conversion efficiency (PCE). The extended thickness of the absorber layer enhances the PCE and JSC. Temperature variations in the thickness of the ETL and HTL have a minimal effect on the PCE and JSC of the device. At standard room temperature (300 K operating temperature), the solar cell parameters are found to be a short-circuit current density (JSC) of 17.93 mA/cm2, open-circuit voltage (VOC) of 1.06 V, fill factor (FF) of 67.46% and power conversion efficiency (PCE) of 17.93%.

Effect of nickel oxide concentration on titanium oxide bilayer photoanode for dye-sensitized solar cell application

The mesoporous titanium oxide has attracted significant attention as a photoanode material for Dye-Sensitized Solar Cells (DSSCs). In the present work, we coated a planar NiO layer on the TiO2 film to minimize charge recombination with the dye and/or electrolyte molecules. The structural, morphological, elemental, optical, and electrical properties of the TiO2 and bi-layered TiO2/NiO films were studied using various characterization techniques. DSSCs based on N3 dye-sensitized TiO2 and bi-layered TiO2/NiO films were fabricated using PI as the redox electrolyte. The photocurrent density–voltage (J–V) characteristics of the DSSCs were studied using a solar simulator. Various parameters, such as open-circuit voltage (Voc), short-circuit photocurrent density (Jsc), and fill factor (FF), were calculated from the J–V characteristics. DSSCs based on bi-layered TiO2/NiO films showed superior performance compared to bare TiO2 films. The J–V characteristics of bilayer film shows enhanced open-circuit voltage (Voc) ~ 0.56 V, short-circuit current density (Jsc) ~ 2.14 mA/cm2, fill factor (FF) ~ 75%, and efficiency (ƞ) ~ 0.91%. The TiO2/NiO solar cell showed a ~ 28% increase in efficiency compared to TiO2-based DSSC. Hence, the bi-layered TiO2/NiO films have potential applications in optoelectronic and photovoltaic devices.

Synergistic effect in ZIF-67/MoS2 entrenched MWCNT photo (electro) catalyst for degradation of tetracycline and alternative to Pt counter electrode in dye-sensitized solar cells

Photocatalytic water purification is an effective environmental protection approach for removing hazardous chemicals in water, besides solar energy conversion is a trustworthy and sustainable choice for the future due to rising energy demands. The present research focus is on synthesis of Metal-Organic Framework (MOF) based composite, Zeolitic Imidazolate Framework-67/Molybdenum Disulfide (ZIF-67/MoS2) entrenched Multi-Walled Carbon Nanotubes (MWCNT) as a catalyst for photodegradation of tetracycline (TC), as well as substitute for Pt counter electrode in Dye-Sensitized Solar Cell (DSSC). The crystalline structure, optical response, shape, porosity, quantum states, and chemical configuration were determined using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS), Photoluminescence spectroscopy (PL), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), and X-ray Photoelectron Spectroscopy (XPS), respectively. The degradation efficiency of ZIF-67/MoS2/MWCNT catalyst under effect of operational parameters namely, photocatalyst dosage, solution pH, coexisting ions, TC concentrations and irradiation time were studied consecutively. ZIF-67/MoS2/MWCNT composite achieved 96.1 % degradation efficiency of TC under white light irradiation. Interestingly, when utilized as a counter electrode in DSSCs, this composite-based electrode delivered the highest Power Conversion Efficiency (PCE) of 3.86 % with a short-circuit current density (JSC) of 7.54 mA cm−2 and open-circuit voltage (VOC) of 0.79 V. The observed enhancement is attributed to lesser peak-to-peak separation (EPP), lower electron lifetime, lower charge transfer resistance (RCT) and higher exchange current density (J0). Based on these findings, ZIF-67 inclusion in MoS2/MWCNT composite is not only an effective catalyst for water treatment but also a good catalyst for I3− reduction in DSSCs.

Multifunctional organic salts synergize interfacial passivation for efficient PSCs

Fully inorganic metal halide perovskite solar cells (PSCs) exhibit high efficiency and excellent thermal stability. However, the presence of surface traps caused by oxygen vacancies in the electron transport layer leads to significant non-radiative charge recombination, which limits both the short-circuit current density (JSC) and photoelectric conversion efficiency (PCE). In this study, we propose a dual-purpose strategy by incorporating the multifunctional organic salt dopamine hydrochloride (DACl) as an additive into the electron transport layer. Firstly, DACl acts as a Lewis base when added to TiO2 films, facilitating improvements in electron transport properties and resulting in higher photovoltaic quality of subsequently deposited perovskite layers. This enhancement significantly improves overall photovoltaic performance. Secondly, DACl's electron-rich aromatic structure and -NH2 functional group can anchor undercoordinated Pb2+ ions and passivate defects within the perovskite film. Additionally, its -OH functional group and charged ion Cl- play crucial roles in improving perovskite grain size and crystallinity. As a result of these modifications, cell efficiency increased ∼35 %, from 9.37 % to 12.70 %, while short-circuit current density increased from 15.44 mA cm−2 to 17.80 mA cm−2 at an illumination intensity of 100 mW cm−2. These findings suggest that introducing DACl into the ETL layer is a promising approach for achieving efficient and stable PSCs.