Generation Solar Cells Research Articles

Mechanochemical synthesis and characterization of poly[(aniline-co-N-(4-sulfophenyl) aniline] nanofibers and its nanocomposite with titanium dioxide nanoparticles and study of their efficiency in hybrid solar cell

The advantages of polyaniline for application in new generation solar cells include its cost-effectiveness, environmentally friendly synthesis, remarkable stability, and the ability to modify the bandgap through the synthesis of its nanocomposites. But a challenge for its nanostructures is the limited solubility in non-toxic solvents, including water, which limits their processability in coating techniques. We overcame this challenge by synthesizing its copolymer with diphenylamine-4-sulfonate and its nanocomposite with titanium dioxide nanoparticles (TiO2NPs). So through a solid-state and template-free technique and using sodium diphenylamine-4-sulfonate, aniline hydrochloride salt, TiO2NPs, and FeCl3∙6 H2O as an oxidant, poly(N-(sulfophenyl)aniline) nanoflowers (PSANFLs), poly [(aniline-co-N-(4-sulfophenyl) aniline] nanofibers (PAPSANFs), poly(N-(sulfophenyl)aniline) nanofibers/titanium dioxide nanoparticles (PSANFs/TiO2NPs), and poly (aniline-co-N-(4-sulfophenyl)aniline nanofibers/titanium dioxide nanoparticles (PAPSANFs/TiO2NPs) were synthesized. Characterization of the synthesized samples was carried out through field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectra, ultraviolet-visible spectra (UV-Vis), cyclic voltammetry (CV), and elemental analysis (CHNS). The FE-SEM images clearly illustrate that the synthesized samples are of nanoscale dimensions. The band gap values of 2.23 eV for PSANFs/TiO2NPs and 1.96 eV for PAPSANFs/TiO2NPs nanocomposites were determined through electrochemical calculations based on cyclic voltammetry curves, showcasing the complementary properties of n and p semiconductors. Using doctor blade method to prepare films from synthesized materials and the architectural pattern of ITO│TiO2NPs│semiconductor sample│Al, all hybrid solar cells are fabricated. The I-V characteristics and power conversion efficiency (PCE) of the samples were examined and discussed. The PCE values for the four samples were found to be in the range of 0.20–0.82 %.

Effects of K, Rb, and Br doping on Cs3Bi2I9 perovskites: A design of experiments approach

This work presents the effect of doping with different species on the structural sites of lead-free halide perovskites, aiming to evaluate the potential of the produced materials as photoabsorbing layers in 3rd generation solar cells. Lead-free perovskite films of Cs3Sb2I9, CsCu2I3, Cs3Bi2I9, and CsPbI3 were synthesized via the spin-coating method and characterized using X-ray diffraction, scanning electron microscopy with chemical microanalysis (SEM-EDS), and Uv-Vis spectroscopy. Computational models based on Density Functional Theory (DFT) were used to simulate the structures and properties of some of the perovskites synthesized in this study, in order to validate the experimentally obtained data. The Cs3Bi2I6Br3 perovskite was subjected to modification through A-site doping with K and Rb and X-site doping with Br, with a comprehensive study on the effects of processing variables, anti-solvent quantity, and crystallization temperature using a 23 experimental design. The outcomes highlighted the critical role of the anti-solvent quantity in structure formation and electronic properties. Toluene, as an anti-solvent, produced unique morphologies not commonly reported. Computational studies were performed using Density Functional Theory (DFT) to complement the experimental findings. The optimization process revealed that Cs3Bi2I9 structures mainly constituted [CsI12] and [BrI6] clusters, with Cs–I and Bi–I average bond lengths consistent with experimental results. X-site Br doping induced slight distortion, while A-site Rb/K doping showed minimal lattice parameter changes. Notably, K-induced morphological alterations suggested potential electronic transformations. From an electronic structure perspective, Cs3Bi2I9 had a band gap of 2.07 eV, slightly increased to 2.10 eV with Br doping. Rb maintained Br-doped structure, while K significantly reduced the band gap to 1.96 eV. These computational results align well with our experimental data, showcasing the accuracy of our calculations in predicting material properties. The results confirmed that the perovskites selected through experimental design and validated by computational simulation are promising semiconductor materials for photovoltaic applications, as well as being a lead-free photoabsorbing material option.

(Invited) Photoelectrode Design for Photoelectrocatalytic Hydrogen Production

Semiconductor nanomaterials hold the keys for efficient solar energy harvesting and conversion processes like photocatalysis and photoelectrochemical reactions. In this talk, we will give a brief overview of our recent progress in designing semiconductor nanomaterials for photoelectrochemical energy conversion including solar hydrogen generation and low-cost solar cells. In more details, we have been focusing on a few aspects; 1) photocatalysis mechanism, light harvesting, charge separation and transfer and surface reaction engineering of low-cost metal oxide based semiconductors including TiO2, BiVO4 as efficient photoelectrode for photoelectrochemical hydrogen production; 2). The design of ultra-stable composites of perovskite-MOF with improved light emitting and photocatalytic performance.1-5 The resultant material systems exhibited efficient photocatalytic performance and improved power conversion efficiency in solar cells, which underpin sustainable development of solar-energy conversion application. References ： 1. Adv. Mater., 2018, doi:10.1002/adma.201705666.2. Angew. Chem, 2019, doi/10.1002/anie.2018105833. Nature Commun, 2020, (2020) 11:21294. Science, 2021, 374, 621.5. Adv. Mater., 2022, 34 (10), 2106776.

Singlet fission photovoltaic cells as dual-wavelength laser power converters compatible with highly efficient solar cells

I applied photovoltaic cells equipped with singlet fission (SF) of molecular systems to dual-wavelength laser power converters (DW-LPCs) that efficiently convert two laser lights of different wavelengths to electricity. When the SF-DW-LPC is illuminated by eye-safe laser light of 1470 nm wavelength emitted from a laser diode, a single photon is converted to a single carrier. On the other hand, a single high-energy photon emitted from a high-power and low-cost laser diode of 808 nm is converted to two carriers by SF owing to its endothermic feature, even though the photon energy is slightly lower than twice the fundamental energy gap. Furthermore, the SF-DW-LPC operates as a highly efficient solar cell. These functions are required for optical wireless power transmission to moving objects including electric vehicles and flying drones. I modeled the photovoltaic process with SF and evaluated the limiting conversion efficiencies by detailed-balance calculations. Conversion efficiencies of the SF-DW-LPC for these two laser lights are competitive with those of the conventional single-junction LPCs dedicated to these wavelengths, respectively. The efficiency under solar light is close to that of the optimally designed SF solar cell. Furthermore, the SF-DW-LPC outperforms other types of DW-LPCs designed on the basis of intermediate band, triplet–triplet annihilation, and multiple exciton generation solar cells. Endothermic SF and carrier/energy extraction into the neighboring acceptors have already been demonstrated. However, molecular systems that apply to 1470 nm have not yet been realized, which is the top-priority issue to be solved to realize highly efficient SF-DW-LPCs.

Excitonic Properties versus Structure Stability Trade‐Off in Halide Perovskite Photovoltaics Caused by van der Waals Interactions

Lead halide perovskites, and their derivatives, are among the most promising photovoltaic materials for third generation solar cells. Despite the large number of available works on some of these materials, excitonic properties whose assessment has been challenging are less investigated. These include quantitative measures of excitonic properties variations with van der Waals (vdW) interactions. Consistent comparisons of how vdW interactions affect phononic and optical properties are also desirable. This work focuses on cubic phases of with X = Cl, Br, I, and MA = methylammonium, using density functional theory simulations including vdW interactions. These cause 30%–38% increase of absolute cohesive energies and 15%–37% reduction of ionic/vibrational contributions to static dielectric constants, along with 10%–29% reduction of exciton Bohr radii and 29%–107% increase of exciton binding energies. The effects on band gaps, frequency‐dependent dielectric functions, and exciton effective masses are less pronounced. Within the Mott–Wannier exciton model, the results suggest a trade‐off between photovoltaic performance and structure stability. The results can help assess stability, feasibility, and performance of hybrid photovoltaic materials.

Enhancing the TiO2 light harvesting ability boosted by Sr2FeTeO6 additives in DSSCs

In this work, novel surface defected lead-free double perovskite oxide (Sr2FeTeO6) has been introduced in dye sensitized solar cells (DSSCs) for the first time. The Sr2FeTeO6 material prepared by solid state method treated at 1200 °C. The DSSC was performed with varying weight percentage (0.01 wt%, 0.03 wt%, 0.05 wt%) of Sr2FeTeO6 additives incorporated with titanium di-oxide (TiO2) photoanode for light harvesting under AM 1.5 solar irradiation. The inorganic double perovskite oxide material as promising additive would be in the future developing 3rd generation solar cell technologies.

Analysis of effect of annealing at high temperature on nickel oxide and zinc oxide thin film for solar cell applications

The use of thin films in solar cell technology has gained substantial interest because of their potential for cost-effective and efficient energy conversion. nickel oxide (NiO) and zinc oxide (ZnO) have been used as potential materials in solar cells application especially third generation solar cells because of their good characteristics, such as high electrical conductivity, chemical stability, resistance to degradation, and abundance and low cost. However, at high temperatures, both NiO and ZnO can undergo thermal decomposition and exhibit crystal defects and grain boundaries. This work investigates high temperature annealing on the morphology, structural, and optical properties of NiO and ZnO thin films. The deposited material was annealed at 500 ℃, 600 ℃, and 700 ℃ and be characterized via scanning electron microscopy (SEM), XRD, and UV-Vi’s spectroscopy. The results showed that inceasing the annealing temperature can improve both ZnO and NiO thin films in structure and appearance. For ZnO, higher temperatures made the grains bigger and more orderly, and for NiO, the process made the grains more organized, bigger in size, and spread out more evenly. However, annealing at high temperature yields a smaller bandgap energy value for both thin films.

Insights into the effect of methylammonium orientation on the crystal structural, electronic structure and optical properties of CH3NH3SnI3

Organic-inorganic hybrid halide perovskites have become an important new generation solar cell materials that are expected to significantly improve the solar conversion efficiency. In this work, the effect of methylammonium (CH3NH3) orientation on CH3NH3SnI3 perovskite is studied by using the first principles of density functional theory. We report the electronic and optical properties of methylammonium in different orientations. It is shown that CH3NH3 orientation leads to an increase in the absorption coefficient and complex refractive index of the material, a redshift in the absorption spectrum, and an enhanced absorption in the visible and near-infrared regions. We find that these changes are strongly influenced by organic-inorganic interactions and octahedral distortions. It suggests that the band gap and optical properties may be effectively modulated by the CH3NH3 rotation orientation, providing valuable insights into the behavior of CH3NH3 embedded in the inorganic octahedra of experiments.

Analysis of Third-Generation Solar Cell Design with Physics of Semiconductor

The paper presents the Analysis of Generation Solar Cell Design with Physics of Semiconductor. The research problem in this study is how to design a high-performance solar cell with novel semiconductor compounds that are fabricated in the laboratory based on the physical parameters. The approach to solving the proposed research problem is based on experimental studies through theoretical research in recent works. The first one is to develop the effective structure for solar cell design and the other is to develop the energy band structure of III-V compound-based third-generation solar cell. The simulation analyses were carried out with the help of MATLAB language. There are many steps to designing high-performance semiconductor devices for real-world applications. The results confirm that the numerical analyses of these two developments could be supported to estimate the outcomes of experimental studies without using real equipment in the laboratory.

Numerical simulation of Sb2Se3-based solar cells

Antimony selenide (Sb2Se3) has remarkable optoelectronic capabilities that make it a promising option for the next generation solar cells. In this work, a solar cell with the structure Al/FTO/CdS/Sb2Se3/Mo is modeled and numerically analyzed using SCAPS-1D program. Furthermore, a Al/FTO/CdS/Sb2Se3/Sb2S3/Mo solar cell structure that uses Sb2S3 as the back surface field (BSF) layer is proposed. A comprehensive examination of photovoltaic characteristics for the solar cells was carried out. The optimization process involved adjusting the operating temperature, series and shunt resistance, doping concentration, bulk defect density, back contact metal work function, and thickness of the absorber layer. The optimized Sb2Se3-based solar cell with Sb2S3 material showed a conversion efficiency of 28.91%, suggesting that Sb2Se3-based solar cells have a great deal of potential for further development.

Electronic structures of lead-free Sn- or Ge-hybrid perovskite halides studied by first-principles calculation

Although CH3NH3PbI3-based perovskite compounds have excellent photovoltaic properties, the lead (Pb) is harmful to the environment, and Pb-free perovskite compounds are needed for next generation solar cells. Theoretical calculations could be one of the good methods to design the Pb-free compounds, and the first-principles calculation was used to predict the properties of the present proposed materials. The instability of organic molecules such as CH3NH3 is also a problem, and alkali elements such as cesium and rubidium could improve the stability. From these point of view effects of tin (Sn) or germanium (Ge) on the lead-free Cs- or Rb- -based perovskites including double perovskite structures were investigated by first-principles calculation in the present work. For the standard single perovskite structures, perovskites with chlorine have suitable band gap energies, higher electron mobilities, and photovoltaic performance compared with other iodine or bromine-based perovskites. For the double perovskite structures, bromine was found to be the suitable halogen, and Ge provided a higher electron density than Sn. The double perovskite structures also provided wider band gap energies and improved stability compared with the standard single perovskites, and the photovoltaic properties could be affected by hybridization of Sn/Ge or halogen ions.

High photovoltaic performance of lead-free Cs2AgInCl6-xBrx perovskite solar cell using DFT and SCAPS-1D simulations

The search of the lead-free highly efficient photovoltaic material is a key challenge for next generation solar cells. The structural, electronic, and optical properties of lead-free double perovskite Cs2AgInCl6-xBrx (x= 0,1,2,3,4,5 and 6) were investigated using density functional theory and its photovoltaic performance by using one-dimensional solar cell capacitance simulator SCAPS-1D. By increasing Br content in Cs2AgInCl6, the lattice parameter increases and the electronic band gap decreases without affecting the direct nature of band gap at Г- point. By mixing Br in Cs2AgInCl6 also provides an effective way to tune the energy band gap. In addition, increasing the Br content in mixed halide composition Cs2AgInCl6-xBrx (x= 0,1,2,3,4,5 and 6) reproduces more dispersive conduction band minima and valence band maxima result in lower effective masses of both charge carriers and consequently higher bipolar carrier mobility. The optical properties of Cs2AgInCl6-xBrx, such as absorption coefficient, reflectivity, dielectric constants, refractive index, and extinction coefficient were investigated with different Br concentrations. Among all compositions, the Cs2AgInClBr5 exhibits better optical properties and behaves as poor reflector and good absorber in the visible region. The photovoltaic performance of different absorber layers of Cs2AgInCl6-xBrx compositions in the perovskites solar cell module with configuration FTO/ETL/Cs2AgInCl6-xBrx /HTL/Au is analysed by using the SCAPS-1D. It is also observed that Cs2AgInClBr5 has high bipolar carrier mobility, relatively higher stability and direct band gap value of 1.75 eV with the PCE of 21.95% in the visible region indicate the suitability of the Cs2AgInClBr5 as a promising lead-free photovoltaic material.

A Review on the Third-Generation Solar Cells: Model, Materials, and Performance.

The present solar cells – first and second generation solar cells are very expensive. They are formed from single crystal and poly-crystal silicon (Si) and Si base, CIGS, CdTe and III-V thin films respectively. This led to the idea of third generation photovoltaic modules. This paper presents works on different types of third generation solar cells. This includes organic photovoltaics (OPVs), copper zinc tin sulfide (CZTS), perovskite solar cells, dye-sensitized solar cells (DSSCs), and quantum dot solar cells.

On the Scope of the Oxygen Plasma Treatment on FTO Electrodes for Electrochemical Processes

The cleaning and/or activation of electrodes for electrochemical purposes using the oxygen plasma treatment has been widely used because of its proven effectiveness to improve the properties of electrodes. Beyond its cleaning effect, the plasma can either create stepped and functionalized carbon-based materials which are active for specific electroanalytes and increase their capacitance [1]. Prussian Blue can also be activated by creating oxygen rich sites thus enhancing its electrochromism [2]. In the case of transparent conductive oxides (TCOs) electrodes such as FTO and ITO-coated glass this treatment has proven to be suitable in the preparation of spray-pyrolyzed titania thin films used as blocking hole layer or electron transporting layer in efficient third generation solar cells [3]. However, the role of this treatment on TCOs when used for electrochemical purposes has not been deeply explored yet. The reason to carry out this study lies in the great number of electrochemical processes that are usually employed for the growth of wide and middle band gap semiconductor metal oxides and chalcogenides with applications in photoelectrochemical and photovoltaic cells [4].To assess the role of the oxygen plasma, FTO was chosen as TCO reference material and the effect of different time exposure and power of plasma was analysed by electrochemical polarization in aqueous media for both anodic and cathodic directions. In the former, PbO2 electrodeposition and oxygen evolution reaction (OER) were considered. In the later, hydroxide generating reactions that usually precipitate in presence of transition metal cations were studied: i) the oxygen reduction reaction (ORR, Figure 1), ii) hydrogen peroxide reduction. Further, the reduction of S8 in DMSO media to sulphide ion was also considered as an aprotic media to growth chalcogenides. Interestingly, all these electrochemical reactions exhibited an increased activation overpotential. The behaviour of treated FTO for OER demonstrated the as implanted oxyanions do not act as source of molecular oxygen as previously claimed [5]. This was verified by the poorly response of ORR after anodic polarizations in acid media.Besides, contact angle measurements allowed to estimate the energetic of the FTO surfaces being these energies correlated with open circuit potential values. Capacitance (Mott-Schottky plots), XPS, UPS and UV-Vis spectroscopy were used to study the semiconductor energy levels of both treated and untreated FTO electrodes. The oxyanion implantation in the oxygen vacancies would be responsible of the sharply diminution of the ORR wave. However, the electrochemical response of the well-known Ferri/Ferro couple only suffered changes under highly aggressive treatments, i.e. for long times or power. Meanwhile, XRD data has shown only slight changes in the structural features of FTO. We can conclude that oxygen plasma treatment is not suitable in FTO for electrochemical purposes, contrary to other deposition methods. Surprisingly, an exception in metals deposition (Ni and Zn) was found.

Investigating the Molecular Orientation and Thermal Stability of Spiro-OMeTAD and Its Dopants By Near Edge X-Ray Absorption Fine Structure

This work describes the utilization of near edge X-ray absorption fine structure (NEXAFS) to investigate the hole transporting material (HTM) 2,2ʹ,7,7ʹ-tetrakis(N,N-di-p-methoxyphenylamine)- 9,9ʹ-spirobifluorene (Spiro-OMeTAD) and its most common dopants, lithium bis-(trifluoromethylsulfonyl) imide (LiTFSI), 4-tert-butylpiridine (tBP) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). Utilizing angle resolved NEXAFS, the orientation of the molecules on the surface can be observed. The data suggests it is difficult to determine any orientational preference for Spiro-OMeTAD deposited on a surface due to the 3D propeller-like geometry of this molecule. Both doped and undoped samples show thermal stability beyond the glass transition temperature of the molecules. Significant changes to the Spiro-OMeTAD spectra were observed with the addition of the dopants, in particular the C K-edge. Differences are also observed in the valence band spectra when dopants are added. It is also demonstrated how the doping combination of LiFTSI with tBP and, F4-TCNQ act as p-type dopants by altering the position of the HOMO levels. The F4-TCNQ induces a larger change in the HOMO levels when compared to the LiTFSI and tBP. These results are important to increase our understanding of Spiro-OMeTAD and the effect dopants have on this material for next generation solar cells.

Effect of solvent and thermal annealing on D18/Y6 polymer solar cells

Organic solar cells (OSCs) as emerging generation solar cells are required to face climate and energy challenges. In this regard, OSCs based on the D18:Y6 active layer with a ratio of 1:1.6 with thermal and solvent annealing as a post-treatment were fabricated. The effect of different thermal annealing with chloroform on the active layer and the cell performance was studied. Optical, morphological and thermal analysis are executed to investigate the effect of thermal with solvent annealing on the D18:Y6 active layer. Photoluminescence (PL), transmission electron microscope (TEM) and atomic force microscope (AFM) reveal that D18:Y6 film treated at 55 °C with chloroform for 5.0 min had the lowest PL intensity, interpenetrating grain networking structures and more smoother surface leads to optimize photo-induced charge transfer and exciton dissociation in the active layer. D18: Y6 blend film annealed at 80 °C with chloroform for 5.0 min exhibits higher roughness of 17.81 nm than 11.60 nm for D18:Y6 blend film treated at 55 °C. As a result, the optimal performance of the fabricated conventional OSCs based on active layer treated at 55 °C with chloroform had short-current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency of 60 mA/cm2, 0.70V, 39.8% and 16.5%, respectively. This study indicates additional thermal annealing with chloroform as a post-treatment enhances the device performance of OSCs.Graphical abstractStudying the effect of solvent vapor annealing with thermal annealing of D18:Y6 layer aspost-treatment on the performance of organic solar cells.

Machine learning-based mapping of band gaps for metal halide perovskites

Recently, perovskite solar cells (PSCs) have received great attentions as the most promising candidate for the next generation solar cells; where the halide perovskite with ABX3 stoichiometry are playing as key components. As a key relevant parameter for various applications of perovskites, the band gap can be modified and optimized by tuning their compositions. In order to enhance the screening efficiency of perovskites with appropriate band gap range for particular applications, this work developed a mapping strategy for band gap range classification through data-driven selected features. This work demonstrates that the proposed features, and further the developed band gap maps, are able to offer a useful initial guiding principle for screenings of potential halide perovskites with fitting band gap ranges and provide opportunities for their compositional design.

Farklı Kalınlıklarda Üretilen TiO2 İnce Filmlerinin Boya Duyarlı Güneş Pili Performansına Etkisi

Dye-sensitized solar cells (DSSC) are known as 3rd generation solar cells. One of the most important parameters affecting the performance of DSSCs is the thin film thickness that forms the photoanode layer. In this study, we examined how 38, 60 and 76 µm thick TiO2 thin films change dye-sensitized solar cell performance. The highest efficiency (4.73%) was seen in the solar cell with 38 µm thin film thickness. In addition, the mineralogical and morphological analyses of the produced TiO2 nanopowders were performed with X-ray diffraction (XRD) and Scanning electron microscopy (SEM). XRD analyses showed that TiO2 was in the anatase crystal phase. SEM photographs confirmed the formation of microspheres in close contact with each other.

Fabrication of solution processable perovskite solar cells under high humid conditions via optimization of TiO2 compact layer

Organic inorganic-based perovskites solar cells (PSCs) are quite prominent as next generation solar cells as they exhibit excellent properties as well as high power conversion efficiency. In spite of the high cost, interfacial recombinations and instability in ambient environment limit their commercialization. Herein, TiO2-based compact layer (c-TiO2) with different thicknesses is employed (<50[Formula: see text]nm) to study the charge transportation at interface and recombination in PSCs fabricated under high humid conditions (R[Formula: see text] 80%). The thickness of CL was varied from 7[Formula: see text]nm to 35[Formula: see text]nm and was optimized by changing the precursor concentration as well as spinning speed. The prepared c-TiO2 and the mesoporous layer of TiO2 (m-TiO2) were thoroughly characterized using Raman spectroscopy, UV-Vis, cyclic voltammetry and electrochemical techniques. Furthermore, CuSCN was used as hole transporting layer (HTL) in PSCs owing to ease of handling and nominal cost. The optimized PSC is found to show that the power conversion efficiency (PCE) improved by 50% on varying the thickness of CL and is stable even under high humid conditions. The elevated performance of PSCs is ascribed to the appropriate thickness of CL which resulted in improved charge transportation and reduced electron hole recombinations.

A Review of Third Generation Solar Cells

Third-generation solar cells are designed to achieve high power-conversion efficiency while being low-cost to produce. These solar cells have the ability to surpass the Shockley–Queisser limit. This review focuses on different types of third-generation solar cells such as dye-sensitized solar cells, Perovskite-based cells, organic photovoltaics, quantum dot solar cells, and tandem solar cells, a stacked form of different materials utilizing a maximum solar spectrum to achieve high power conversion efficiency. Apart from these solar cells, other third-generation technologies are also discussed, including up-conversion, down-conversion, hot-carrier, and multiple exciton. This review provides an overview of the previous work in the field, alongside an introduction to the technologies, including their working principles and components. Advancements made in the different components and improvements in performance parameters such as the fill factor, open circuit voltage, conversion efficiency, and short-circuit current density are discussed. We also highlight the hurdles preventing these technologies from reaching commercialization.