Fabrication Of Solar Cells Research Articles

Synthesis of novel Cu/Fe based benzene Dicarboxylate (BDC) metal organic frameworks and investigations into their optical and electrochemical properties

In the recent past Metal-organic frameworks (MOFs) based thin films have demonstrated superior performance in various technological applications such as optical and optoelectronic devices, electrochemical energy storage, catalysis, and sensing. Herein we report tuning the optical performance of stable complexes using Cu and Fe metal ions with carboxylate benzene dicarboxylic (BDC), leading toward the formation of novel MOF structures. The formation of Cu-BDC and Fe-BDC were confirmed by XRD and SEM studies. The thermal stability of two MOFs was investigated, indicating that, the Cu-BDC is more stable than Fe-BDC. Further, the optical properties were investigated in the wavelength range 325–1100 nm, and the Fe-BDC exhibited greater optical transmission properties than Cu-BDC by 33 %, as investigated by Wemple-DiDomenico and Tauc models. The dispersion parameters related to optical studies for Cu-BDC were better in comparison to Fe-BDC, which could be attributed to the increase in Cu valence electrons due to an increase in the number of cations. The electrochemical behavior in terms of CV measurements shows the presence of pseudo capacitance in both Fe-BDC and Cu-BDC MOFs. The improved CV performance of Cu-BDC MOF suggests that it could be used as a storage material. This work successfully demonstrates the tailoring of optical properties related to MOF thin films through the formation of stable complexes using BDC as a potential material for the fabrication of OLED's and Solar cells. The improved CV performance suggests that these MOF based materials could be used as anodes in fabrication of batteries or supercapacitors.

Effect of Thickness on Structural, Morphological, and Optical Properties for Nanocrystalline Thin Films of Cd1-xSnxS, for Optoelectronic Applications

Thin films of Sn1-xCdxS nanocrystals (X=0,0.7, and 1) with different thicknesses 200, 300, and 400 nm were prepared on glass bases at 300 C by the participation method and chemical spray pyrolysis method (CSP). The effect of the concentration of Sn and thickness on the structural and optical properties of the prepared films was studied. The films were characterized to evaluate the structure, transmittance, and optical energy band gap. X-ray diffraction (XRD) studies showed that the films were polycrystalline with hexagonal and orthogonal structures. XRD and atomic force measurement results showed that the grain size increases with its thickness. The optical band gap energies and optical transmission and absorption types of the membranes were determined from the optical transmittance spectra. Optical absorption studies in the wavelength range 200-1100 nm showed that the energy gap values of the films decrease from 2.48-1.95 eV, 2.41-1.92 eV, and 2.3- 1,89 eV with increasing Sn concentration and with increase the thickness 200, 300, and 400 nm respectively. The best properties of the prepared material were determined for its possible use in the manufacture of solar cells.

Synergistic Effect of Alkylammonium Chlorides to Trigger an Ultrafast Nucleation for Antisolvent‐Free Perovskite Solar Cells Processed from 2‐Methoxyethanol

Abstract2‐Methoxyethanol (2ME), as a more environmentally friendly solvent with a lower boiling point compared to dimethylformamide, is ideal for the fabrication of perovskite solar cells (PSCs). However, when 2ME is used for antisolvent‐free deposition of perovskite films, an uncontrolled nucleation process and an easy phase transition to the δ‐phase often occur. Herein, an ultrafast nucleation process is developed using methylamine chloride (MACl) and n‐butylammonium chloride (BACl) as dual additives in 2ME without further solvent addition. While MACl can rapidly induce MACl‐based nuclei to initiate the nucleation process for formamidinium lead iodide (FAPbI3), the addition of BACl to the precursor with MACl can further increase the nucleation rate and density of nuclei, and bypass the transition from δ‐ to α‐phase during crystal growth to obtain a highly crystalline and pinhole‐free perovskite film. As a result, the FAPbI3 PSCs achieve a power conversion efficiency (PCE) of 23.6%. This work provides a new inspiration for controlling the crystal quality of perovskite thin films via nucleation rate suitable for upscaling.

Scalable large area perovskite solar cell modules fabricated with high humidity tolerance by vacuum deposition

Vacuum deposition is promising for large-area, high-throughput production of perovskite solar cells (PSCs). However, the strict low humidity control increases the costs for manufacturing facilities and hinders the large-scale production of PSCs. In this work, a sequential deposition method was used to prepare the perovskite intermediate phase, and the impact of ambient humidity was studied during the annealing process. It is shown that proper humidity has a positive effect on the perovskite layer, which is conducive to accelerate the reaction between organic salts and PbI2 and improve the surface morphology of the film. The perovskite annealing under 55 % relative humidity exhibits fewer defects and faster carrier transport kinetics. The resulting PSCs, with all layers fabricated adopting vapor deposition, yield a power conversion efficiency (PCE) of 15.01 % for the large area modules of 100 cm2 (active area 64.8 cm2). More impressively, the PCE of the unpackaged cell modules remained above 80 % after being placed in ambient air for 1200 h. The results open a promising way for scalable fabrication of humidity-tolerant large-area perovskite solar cell modules and shed light on the industrial production of PSCs.

Annealing Time Dependence in the Fabrication of Bismuth-based Perovskite Solar Cells (Bi-PeSCs) by the Hot Immersion Method

Lead-free perovskite solar cells have attracted attention as an environmentally friendly future energy source. However, their performance is still low at present due to the poor morphology of the film and the complicated process of fabrication. The annealing period, as a key parameter, has been identified to control the morphology of MA3Bi2I9 (MBI) perovskite film fabricated by the Hot Immersion Method (HIM) with the annealing period varying between 5 to 25 minutes. SEM images visually depicted that a longer period of annealing induced perovskite film to form a larger crystallite size with a compact film, resulting in a rougher surface. The MBI films fabricated at 25 minutes showed a high crystallinity of films and exhibited a high absorption with a longer absorption wavelength and a narrow bandgap, leading to enhanced solar cell performance. By optimizing the annealing time, the efficiency of the device has been enhanced almost eight times compared to a shorter period of annealing. Our findings suggest that the compact MBI films can be obtained by using this simple method (HIM), and yet the performance of solar cell devices can be achieved, thus providing another alternative way to fabricate MBI-based perovskite solar cells (PeSC’s) in the future.

Green Anisole as Antisolvent in Planar Triple-Cation Perovskite Solar Cells with Varying Cesium Concentrations.

The feasibility of replacing toxic chlorobenzene antisolvents with environmentally friendly anisole in the fabrication of planar triple-cation perovskite solar cells was explored here. The successful integration of anisole not only ensures comparable device performance but also contributes to the development of more sustainable and green fabrication processes for next-generation photovoltaic technologies. Nevertheless, to ensure the possibility of achieving well-functioning unencapsulated devices whose working operation depends on outdoor atmospheric conditions, we found that adjusting the cesium concentrations in the perovskite layers enabled the electrical characterization of efficient devices even under high relative humidity conditions (more than 40%). We found that 10% of CsI in the precursor solution will make devices with low hysteresis indexes and sustained performance stability over a 90-day period both with cholorobenzene and anisole antisolvent. These results further confirm that green anisole can replace chlorobenzene as an antisolvent.

One-step Cu-assisted chemical etching at room temperature of inverted pyramid array for high-performance crystalline silicon solar cells

Previous studies on the one-step Cu-assisted texturization of silicon wafers have predominantly focused on etching conditions at relatively high temperatures, which are unsuitable for the mass production of solar cells in industrial settings. In this study, we introduced the one-step Cu-assisted chemical etching (Cu-ACE) technique at room temperature to obtain large-area silicon inverted pyramid (IP) array structures. Based on this structure, diamond wire saw (DWS) mc-Si solar cells can achieve a balance between enhanced light trapping and lower carrier recombination by optimizing the concentration of the component Cu(NO3)2/HF/H2O2 in the etchant solution and the etching time during the Cu-ACE process. As a result, these solar cells deliver a power conversion efficiency (PCE) of 18.20 %, which is 1.99 % absolute higher than solar cells using traditional etching techniques. This work paves a new pathway toward the mass production of high-efficiency crystalline Si solar cells, offering a cost-effective and simple texturization approach.

Chemically processed CdTe thin films for potential applications in solar cells – Effect of Cu doping

Thin films of cadmium telluride (CdTe) have attained the attention of researchers due to the potential application in solar cells. However, cost-effective fabrication of solar cells based on thin films along with remarkable efficiency and control over optical properties is still a challenging task. This study presents an analysis of the structural, optical and electrical properties of undoped and Cu-doped CdTe thin films fabricated on ITO coated glass substrates using an electrodeposition process with a focus on practical applications. Electrolytes of cadmium (Cd), tellurium (Te) and copper (Cu) are prepared with a low molarity of 0.1 M. Thin films are deposited by keeping current density in the range of 0.12–0.3 mA/cm2. Copper doping is varied (2-10 wt%) for the optimized sample. X-ray diffraction crystallography indicates that both undoped CdTe and Cu-doped CdTe films crystallize into a dominant hexagonal lattice. Direct energy band gap is observed for both undoped and doped conditions. The study revealed a drop in the optical band gap energy to ∼1.46 eV with the increase in doping (Cu) concentration from 2 to 10 wt%. Increase in mobility and conductivity is observed with the increase in current density of the deposited undoped CdTe thin films. Whereas, Cu doping of 6 wt% produced thin films with acceptable mobility and conductivity for the doped samples. Furthermore, photoluminescence (PL) spectroscopy unveiled a multitude of emission peaks encompassing the visible spectrum, arising from the combination of electrons and holes through both direct and indirect recombination processes. Findings of this study suggest that chemically produced CdTe thin films would be suitable for use as low-cost applications pertaining to solar cells.

Pathways toward commercial perovskite/silicon tandem photovoltaics.

Perovskite/silicon tandem solar cells offer a promising route to increase the power conversion efficiency of crystalline silicon (c-Si) solar cells beyond the theoretical single-junction limitations at an affordable cost. In the past decade, progress has been made toward the fabrication of highly efficient laboratory-scale tandems through a range of vacuum- and solution-based perovskite processing technologies onto various types of c-Si bottom cells. However, to become a commercial reality, the transition from laboratory to industrial fabrication will require appropriate, scalable input materials and manufacturing processes. In addition, perovskite/silicon tandem research needs to increasingly focus on stability, reliability, throughput of cell production and characterization, cell-to-module integration, and accurate field-performance prediction and evaluation. This Review discusses these aspects in view of contemporary solar cell manufacturing, offers insights into the possible pathways toward commercial perovskite/silicon tandem photovoltaics, and highlights research opportunities to realize this goal.

Donor–acceptor mutually diluted heterojunctions for layer-by-layer fabrication of high-performance organic solar cells

Donor–acceptor mutually diluted heterojunctions for layer-by-layer fabrication of high-performance organic solar cells

Pressure-induced investigation of structural, electronic, optical, and mechanical properties of BaCeO3

The exploration of the hydrostatic pressure effect on the characteristics of materials is essential for various applications. Our study uses Density Functional Theory (DFT) to investigate the pressure-induced influence on the structural, electronic, optical, and mechanical properties of BaCeO3. According to formation enthalpy and Born stability criteria, BaCeO3 is mechanically and thermodynamically stable from 0 GPa to 80 GPa. The tunable band gap of BaCeO3 within the visible spectrum under applied pressure makes it a potential candidate for absorber layer fabrication of solar cells. The electronic state, mainly attributed to O-2p in the valence band (VB) and Ce-4f in the conduction band (CB), is observed through Partial Density of States (PDOS), although its intensity varies with pressure. The refractive index shows that pressurized BaCeO3 is appropriate for photonics. Its significant absorption at high energy under pressure makes it an excellent candidate for Ultraviolet (UV) detectors, and it also has low light reflection, with static values routinely less than 0.2. Additionally, as pressure increases, elastic constants, elastic moduli, ductility, machinability index, and anisotropy all increase, except for hardness, which decreases. BaCeO3 is approaching to minimal bond stretching with pressure according to Kleinman parameter. These pressure-induced changes in mechanical properties have potential applications in flexible electronics, structural uses, and more.

Computational design of new polymers having low exciton binding energy for organic solar cells fabrication: Chemical generation and visualization

Conventional organic solar cell (OSC) fabrication, based on the hit and trial methodology, is quite laborious and lethargic, requiring extensive human workforce and instrumental resources. Recent advancements in machine learning (ML) approaches have revolutionized selection of the suitable active polymeric layer for OSC devices. Among numerous aspects impacting efficacy of the OSC fabrication, the lower exciton binding energy (Eb) was found one of the most crucial factors. The dataset containing Eb values was prepared from already documented literature on polymeric active layers of OSC devices. Various ML models were applied and tested to predict Eb values accurately, however, the random forest regressor model was proved to be the most efficient one. The ML analysis was further utilized to develop a new and novel chemical database that could be utilized as an active layer for the fabrication of OSCs. The synthetic accessibility (SA) score was also investigated to explore the relative ease by which a proposed polymeric material could be synthesized in practical lab. Interestingly, analysis of the top thirty generated polymeric materials exhibited extremely decent SA score, and remarkably lower Eb values; both properties are highly desirable for the fabrication of efficient OSCs. Further, we also applied deep learning approach to generate and screen new monomers with lower Eb and SA score. This effort reveals significance of the computational data-driven approaches for real-life applications. Our current contribution of the novel polymeric materials database having extremely low Eb values could be valuable for the fabrication of efficient OSC devices.

Comparative study of indium tin oxide and indium gallium zinc oxide as potential n-type materials for the fabrication of all inorganic transparent solar cells

This study focuses on transparent solar cell device fabrication using amorphous and crystalline oxide semiconductors. Radio frequency magnetron sputtering was used to fabricate Fluorine doped Tin Oxide/n-Indium Gallium Zinc Oxide/p-Nickel Oxide/Silver nano wires and Fluorine doped Tin Oxide/n-Indium Tin Oxide/p-Nickel Oxide/Silver nano wires devices. Deposition conditions for n and p-type semiconductors were optimized and analyzed. Silver Nanowires were spin-coated as top contacts. The solar cells were exposed to 365 nm, and their current voltage characteristics were analyzed. This novel approach using amorphous oxide semiconductors provides insights for high-efficiency device fabrication.

Sequential fabrication of multiple Ge nanomembranes from a single wafer: Towards sustainable recycling of Ge substrates

Germanium (Ge) substrates are employed for III-V multijunction solar cells (MJSCs). However, due to limited availability and environmental impact, Ge is a critical raw material. Detachable Ge nanomembranes (NMs) are gaining attention to reduce Ge consumption through substrate reuse. The Porous germanium Efficient Epitaxial LayEr Release (PEELER) process enables Ge NM detachment and substrate reuse, reducing costs and Ge material consumption. In this work, we demonstrate the sequential production of three NMs from one parent substrate using the PEELER process, yielding monocrystalline NMs, with a surface suitable for further epitaxial growth of III-V layers (RMS < 3.2 nm). By avoiding the costly Chemical Mechanical Polishing (CMP), our approach enables a more economical and sustainable production of high-efficiency Ge-based solar cells, compared to the conventional production process.

Enhancing Efficiency and Intrinsic Stability of Large‐Area Blade‐Coated Wide‐Bandgap Perovskite Solar Cells Through Strain Release

AbstractThe realization of efficient large‐area perovskite solar cells stands as a pivotal milestone for propelling their future commercial viability. However, the upscaling fabrication of perovskite solar cells is hampered by efficiency losses, and the underlying growth mechanism remains enigmatic. Here, it is unveiled that a prevalent upscaling technology, namely blade‐coating, inherently triggers top‐down inhomogeneity strains, predominantly concentrated on the surface of wide‐bandgap perovskite films. Through strain mitigation strategies, the perovskite films exhibit reduced halide vacancies, leading to enhanced stability and improved optoelectronic characteristics. Consequently, the blade‐coated perovskite solar cells achieve minimal efficiency loss when transitioning from small‐area to large‐area devices, enabling the realization of 1 cm2‐area 1.77 eV‐bandgap cells with a remarkable efficiency of 18.71%. Additionally, the strain‐relieved device exhibits an exceptional 109% retention of its initial efficiency even after 400 h of continuous operation, in stark contrast to the control device which experiences a decline to 91%. Furthermore, the resulting 4‐terminal all‐perovskite tandem solar cells crafted utilizing blade‐coated 1.77 eV‐bandgap subcells achieve a maximum efficiency of 27.64% (stabilized at 27.28%). This study not only sheds light on the intricacies of upscaling preparation techniques but also overcomes potential obstacles that can impede the trajectory toward achieving large‐scale perovskite solar cells.

Formamidinium Perovskite Deposition in Ambient Air Environment for Inverted p-i-n Solar Cells.

In order to move towards large-scale fabrication, perovskite solar cells need to detach themselves from strictly controlled environmental conditions and, to this end, fabrication in ambient air is highly desirable. Formamidinium iodide perovskite (FAPI) is one of the most promising perovskites but is also unstable at room temperature, which may make the ambient air deposition more difficult. Herein, we investigated different formulations of pure FAPI for the fabrication of perovskite solar cells (PSCs) in air. We found that formulations using a mixture of N,N-Dimethylformamide (DMF): N-methyl-2-pyrrolidone (NMP) and only dimethyl sulfoxide (DMSO) are suitable for the deposition in air. To fabricate inverted p-i-n solar cells, we tested different hole transporting layers (HTLs) and observed the effects on the wettability of the perovskite solution and on the performance. A self-assembly monolayer of 2PACz (2-(9H-Carbazol-9-yl)ethyl]phosphonic acid) was found to be the best option as a HTL, allowing us to achieve efficiencies >15% on both FTO and ITO.

Correction: Recent trends on the application of phytochemical-based compounds as additives in the fabrication of perovskite solar cells

Correction for ‘Recent trends on the application of phytochemical-based compounds as additives in the fabrication of perovskite solar cells’ by Naomy Chepngetich et al., Energy Adv., 2024, 3, 741–764, https://doi.org/10.1039/D4YA00025K.

Exploring the interplay of the water–methanol solvent admixture on the optoelectronic properties of spray pyrolyzed fluorine-doped tin oxide thin films and their potential use in solar cell fabrication

A FTO thin film, M90, prepared using 90 vol% CH3OH, exhibits the highest FOM, indicating its potential use in photovoltaics and other applications.

Luminescence spectrum of cadmium chalcogenide photovoltaic film structures and their power enhancement

A technology has been developed for producing photovoltaic film structures of CdTe, CdTe:In, CdTe/CdS by thermal vacuum deposition, which allows increasing their operating power. An analysis of their low- temperature photoluminescence spectra shows a significant increase in their spectral sensitivity. It has been experimentally shown that there is a clear correlation between the anomalous photovoltaic (APV) properties and the shape of the intrinsic photoluminescence band of obliquely deposited CdTe films. The photoluminescence spectrum of a polycrystalline CdTe film with APV property is qualitatively different from the spectra of a single crystal, large-block polycrystal and single microcrystal. The main contribution to the photoluminescence of the film comes from radiative recombination of free carriers (A-line with half-width ΔEA≈14.2±0.1 meV) and edge luminescence with a wide doublet structure (B- and C - lines with half- widths 18.5±0.1 meV and 32.2±0.1 meV). When doped with In impurities and as a result of heat treatment, the emission spectrum is greatly transformed in accordance with the change in the photoelectric properties of the film. In the photoluminescence spectrum of a CdTe layer in a CdTe/CdS heterostructure grown under identical technological conditions as a CdTe monolayer, an additional broad spectral line appears due to the presence of a heterointerface, the superhot region disappears, and the A-emission line narrows somewhat (ΔEA≈11.2±0.1 meV), which significantly differ the studied film structures from the known CdS/CdTe heterosystems of other authors. The proposed method for analyzing low-temperature photoluminescence spectra makes it possible to purposefully control the technology for manufacturing photovoltaic film structures. The results obtained are of interest for film optoelectronics and solar cell manufacturing.

Enhancing perovskite solar cell performance through PbI2 in situ passivation using a one-step process: experimental insights and simulations.

The in situ passivation of a methylammonium lead triiodide (MAPbI3) phase spin-coated via a one-step process was experimentally investigated to elucidate their fundamental properties. Structural analysis revealed that MAPbI3 adopts a tetragonal crystal structure with a small excess of PbI2 (0.03 M) segregating at grain boundaries. Optical characterization indicated a band gap of 1.53 eV, highlighting the material's potential as an effective visible light absorber. To facilitate the fabrication of efficient perovskite solar cells (PSCs), we employed a primary n-i-p planar structure (ITO/SnO2/MAPbI3/spiro-OMeTAD/Au) in drift-diffusion SCAPS-1D simulations using experimental data from MAPbI3 layers containing excess PbI2. The simulations predicted a high power conversion efficiency (PCE) of approximately 24%. We further analyzed the impact of series resistance, shunt resistance, MAPbI3 thickness, defect density, as well as radiative and Auger recombination on photovoltaic performance, aiming to identify optimal parameters for enhanced device efficiency. Additionally, the use of ohmic contacts with AZO and IZO as the front and rear contacts, respectively, in the optimized device structure (AZO/SnO2/MAPbI3/spiro-OMeTAD/IZO) resulted in a PCE of 26.03%. These findings provide valuable insights for future research aimed at achieving high-efficiency bifacial MAPbI3 perovskite solar cells.