Films For Solar Cell Applications Research Articles

Active Passivation of Anion Vacancies in Antimony Selenide Film for Efficient Solar Cells.

Binary antimony selenide (Sb2Se3) is a promising inorganic light-harvesting material with high stability, non-toxicity and wide light harvesting capability. In this photovoltaic material, it has been recognized that deep energy level defects with large carrier capture cross section, such as VSe (selenium vacancy), lead to serious open-circuit voltage (VOC) deficit and in turn limit the achievable power conversion efficiency (PCE) of Sb2Se3 solar cells. Understanding the nature of deep-level defects and establishing effective method to eliminate the defects are vital to improving VOC. In this study, we propose a novel directed defect passivation strategy to suppress the formation of VSe and maintaining the composition and morphology of Sb2Se3 film. In particularly, through systematic study on the evolution of defect properties, we reveal the pathway of defect passivation reaction. Owing to the inhibition of defect-assisted recombination, the VOC increases, resulting in an improvement of PCE from 7.69% to 8.90%, where is the highest efficiency of Sb2Se3 solar cells prepared by thermal evaporation method with superstrate device configuration. This study proposes a new understanding of the nature of deep-level defects and enlightens the fabrication of high quality Sb2Se3 thin film for solar cell applications. This article is protected by copyright. All rights reserved.

Pinhole Healing of Pristine FAPbI3 Films via Homogeneous Recrystallization with Mixed Vapor of Tetramethylene Sulfoxide and Anisole

AbstractThe preparation of pristine formamidinium lead tri‐iodide (FAPbI3) perovskite films for solar cells applications can be very challenging without methylammonium containing additives. The pinhole‐rich films prepared by methylammonium‐free approach limit the performance of the pristine FAPbI3 perovskite solar cells (PSCs). This work proposes a recrystallization method employing mixed solvent annealing (MSA) to heal the pinholes in pristine FAPbI3 perovskite films. The tetramethylene sulfoxide vapor is demonstrated most effective in grains‐merging and pinhole healing, while the addition of a secondary solvent vapor of anisole significantly improved the uniformity of TMSO vapor distribution. The pristine FAPbI3 PSCs prepared with MSA recrystallized film achieved power conversion efficiencies up to 22.43% and 16.54% on small cells (0.105 cm2) and mini‐modules (12.6 cm2), respectively, showing great potential in upscaling fabrication of perovskite photovoltaics with pristine FAPbI3.

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.

Characterization of Titanium Dioxide Thin Films Grown on Glass Substrate by Gasified-Thermal-Carrier-Assisted Evaporation Technique: Impact of Deposition Time

In this study, a gasified thermal carrier assisted vapor deposition technique has been used to deposit titanium dioxides thin films of 90, 270, and 480 nm, thicknesses on glass substrates at growth times of 1, 2, and, 3 hours respectively. Varied nondestructive techniques were employed to investigate the impacts of deposition time on the structural, optical, and electrical properties of the TiO2 thin films. X-ray diffraction (XRD) showed that crystals of a polycrystalline nature were preferentially oriented along the (101) direction. The analysis of the chemical composition of the films by energy-dispersive X-ray (EDX) spectroscopy demonstrated very pure TiO2 thin films that were free of contamination and impurities. The SEM images indicated that the TiO2 thin films were cluster forms, with increasing sizes of with the growth times of 1, 2, and, 3 hours, and these times produced thicknesses of 90, 270, and 480 nm, respectively. The study of the optical properties using ultraviolet-visible (UV-Vis) spectroscopy revealed a thickness-inverse relationship between the films’ optical transmittance levels (from 92% to 78%) and their corresponding energy bandgaps. The electrical properties of the TiO2 films were analyzed via a Hall effect measurement system. The electrical resistivity levels of the films were highly correlated with the thicknesses of the films. The lowest value of electrical resistivity for the highest thinness was 55×103Ω· cm. The films showed high densities of carriers, with concentrations of 85×1012 to 35×1013 N (cm−3), and sufficiently low shift resistance levels. According to the obtained results, three hours, which led to the growth of a 270 nm thickness, could be considered as the ideal deposition time for TiO2 thin films for solar cell applications.

Effect of annealing temperature on bismuth vanadate nano thin films for solar cell applications

Bismuth vanadate (BiVO4) has been used as the photoanode electrodes in ferroelectric solar cells owing to its unique combination of properties: a narrow bandgap among ferroelectrics, economic viability, negative conduction band edge, and remarkable stability. The present work explores the fabrication and characterization of BiVO4 thin films prepared via spin coating, with a specific focus on elucidating the influence of the annealing temperature (400–550 °C) on their structural, optical, and photovoltaic properties. From X-ray diffraction (XRD) analysis, it is observed that higher annealing temperatures have promoted the formation of larger grains, enhanced crystallinity, and induced a preferred crystal orientation characteristic of the monoclinic scheelite structure. Tauc plot analysis shows the dependence of the optical band gap on the annealing temperature for BiVO4 thin films. The band gap values have decreased slightly from 2.50 eV at 400 °C to 2.44 eV at 550 °C. This is indicated by the slightly narrowed bandgap, which influences the structure of the material or defect states at higher annealing temperatures. A narrower bandgap allows for the absorption of lower-energy light, potentially improving the light absorption efficiency of BiVO4 thin films in photoanode applications. The influence of annealing temperature on BiVO₄ thin film solar cell performance was investigated further through the analysis of open-circuit voltage (Voc), short-circuit current (Isc) and power conversion efficiency.

Structural Evolution of Sequentially Evaporated (Cs,FA)Pb(I,Br)3 Perovskite Thin Films via In Situ X‐Ray Diffraction

Evaporation of perovskite thin films for solar cell applications is a solvent‐free, well controllable, and scalable deposition path with promising prospects for commercialization. Compared to commonly applied simultaneous co‐evaporation of various halide precursor salts, sequential evaporation followed by an annealing step allows to better control the amount of deposited precursors, and has the potential to largely improve reproducibility. In this work, Cs/formamidinium (FA)‐based lead iodide perovskites are deposited via sequential evaporation in a vacuum chamber and the phase formation and evolution of different precursor‐stacking sequences and annealing conditions are investigated with in situ X‐ray diagnostics. In addition, some Br is added to investigate the effect of halide intermixing. The stacking sequence is found to strongly influence the formation of dominant phases as well as the preferential orientation and HGHmorphology of the as‐deposited films. These variations in turn affect the diffusion and conversion during thermal annealing and ultimately the conversion ratio of the final perovskite layers. For example, it is found that starting the stacking sequences with the A cations (CsI, FAI) favors a fast and complete conversion of the perovskite phase. However, the result is the formation of perovskite layers with large voids.

Crystal reconstruction and defect healing enabled high-quality Sb2Se3 films for solar cell applications

A post-sulfurization technique has been developed to refine Sb2Se3 crystallization. This process enables high-quality Sb2Se3 with a smooth surface, large compact crystal grains and benign [hkl] growth orientation. It also mitigates the device VOC deficit, owing to the healed deep level defects.

Effect of chromium doping on the band gap tuning of titanium dioxide thin films for solar cell applications

A simple and inexpensive spray pyrolysis deposition (SPD) approach was used to produce TiO2 and Cr (2–8) at.%-doped TiO2 thin films. To explore the morphological features of the films, FE-SEM micrographs were used and found that 6 and 8 at.% TiO2:Cr films had fibrous patterns with diameters of 0.45 and 0.78 μm, respectively, while the remainder of the films were agglomerated particles. From X-ray diffraction investigation, it was found that the TiO2 thin films had an anatase crystal phase (tetragonal) up to 6 at.% Cr doping, while an anatase-rutile mixed crystalline phase was identified for 8 at.% Cr doping. The crystallite size of the pristine TiO2 film was 35 nm, while for TiO2:Cr films, it ranges from 35 to 46 nm. The Fizeau fringes technique was employed to measure the thickness of the TiO2 film and 165 nm was found for pristine TiO2 and 164–180 nm for TiO2:Cr films. UV–visible spectroscopy was used to study optical properties such as absorbance, refractive index, optical band gap, dielectric constant, and optical conductivity. As the Cr concentration increases, the optical band gap decreases from 3.40 eV to 2.70 eV. Using the four-point probe method, it was found that the resistivity changes with temperature and is also affected by the Cr content.

Impact of post-deposition annealing on the optical, electrical, and structural properties of CdS thin films for solar cell applications

In this study thermally evaporated cadmium Sulfide (CdS) thin films with the thickness of 100 nm were fabricated at 150 °C under the pressure of 2 × 10−5 mbar and subjected to annealing treatment at various temperatures. The optical, electrical, and structural properties of CdS thin films, which were influenced by annealing treatment, were then studied using ultraviolet–visible (UV–Vis) spectroscopy, Hall effect measurement system, X-ray diffraction (XRD), Raman spectroscopy and Atomic force microscopy (AFM) analysis. The energy band gap was found to decrease from 2.402 eV for the as-grown CdS film to 2.250 eV for the film annealed at 450 °C. The electrical parameters of CdS thin films, such as carrier concentration, resistivity and mobility, were then calculated using the Hall effect measurement system; these were improved with the increase of the annealing temperature up to 350 °C. The crystallite size of the preferred (111) orientation was in the range of 12–40 nm and increased with annealing temperature. The increase in the intensity of peaks and shifting peaks toward the single-crystal mode was observed in the Raman spectra of the annealed CdS thin films. The AFM images also revealed that the film roughness increased with heat treatment. Further, the obtained SEM images showed the uniform surface of the film. The efficiency of the designed solar cell was in the range of 21.84–22.18 %; it was increased by using the annealed CdS films. The present work, thus, introduced the annealed CdS thin film at 350 °C as a promising window layer to fabricate highly efficient CdTe-based solar cells.

Silicon Solar Cell with Tunneling Oxide on Sulfur‐Deficient Intrinsic MoS2 Thin Film

The thermolytic growth of molybdenum disulfide thin films for solar cell applications is investigated. The thin films are spin‐coated and thermally annealed, and they show a sulfur‐deficient nanosheet structure with various spectral emissions. The intrinsic thin films are used to form heterostructures in silicon solar cells. Two types of Si solar cells are fabricated using a MoS2/p‐Si heterojunction structure and MoS2/SiOx/pn‐Si tunneling structure. The former heterojunction cell does not show photovoltaic cell character. However, the later oxide tunneling cell shows a short‐circuit current of 8.23 A, an open‐circuit voltage of 0.602 V, and a conversion efficiency of 14.6%. This indicates that the sulfur defect‐induced MoS2 thin film shows an n‐type Ohmic character, but it might not form a stable interfacial charge depletion layer with p‐Si wafers in large‐scale cell fabrication.

Unveiling SiO2 nanoparticle derived from rice husk doped P-type Cu2O thin films for solar cell application

Unveiling SiO2 nanoparticle derived from rice husk doped P-type Cu2O thin films for solar cell application

Effect of deposition voltage on the properties of electrodeposited CdZrS thin films for solar cell application

The electrodeposition procedure was carried out utilizing a two-electrode system on fluorine-doped tin oxide (FTO) substrates, with the deposition voltage for CdS set at 1450 mV and for CdZrS at the range of 1450, 1550, and 1600 mV. The structural results show that both CdS and CdZrS thin films exhibit cubic structure. Surface image analysis shows that the FTO substrate was covered by film. The shape and grain size of the films is varied with deposition voltage. Elemental composition analysis confirmed the presence of desired elements Cd, Zr, and S on the deposited samples. CdS and CdZrS surfaces have an average surface roughness in the range of (3.2−19.6) nm. The optical properties of the films revealed a bandgap energy of 2.25 eV for CdS and (2.09−2.39) eV for CdZrS. The electrodeposited CdZrS thin films have potential applications as buffer layers in solar cell devices.

Experimental and theoretical study of electrodeposited CuInS2 thin films for solar cell applications

Absorbent CuInS2 layers were successfully prepared using an electrodeposition technique on ITO-coated glass, followed by a sulfidation process. The effects of sulfurization time on the structural, morphological and optical properties of samples were examined. The structure, morphology, and composition of synthesized films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS), while the optical properties were examined by UV-VIS-NIR spectrophotometry. The experimental results show that the resulting films (CIS) are polycrystalline with a chalcopyrite structure with a preferential orientation along the (112) plane and show that Cu atoms separate near the grain boundaries and a wide bandgap value of 1.52 eV. The SEM study showed that the surface of the CIS films was dense and uniform. Theoretical calculations carried out by TB-mBJ showed a wide bandgap of 1.15 eV, a high refractive index, and absorption coefficient in the visible region which is consistent with the experimental results found.

Low-cost fabrication of single chalcogenide CuInGaSe2 sputter target and its thin films for solar cell applications

Low-cost fabrication of single chalcogenide CuInGaSe2 sputter target and its thin films for solar cell applications

Microwave-induced band gap attenuation of novel manganese zinc aluminum sulfide kesterite nanomaterials for optimal photovoltaics

Recently, kesterite (copper zinc tin sulfide, CZTS) have emerged as a promising alternative active layer to cadmium telluride and copper indium gallium selenide for low-cost thin films for solar cell applications due to its high absorption coefficient, direct band gap, natural abundance, and low toxicity. The photovoltaic power conversion efficiency achieved with CZTS is still very low when compared to silicon, thereby hindering its commercialization. Developing new materials with improved optical and photovoltaic properties is, therefore, encouraged. Here, we report for the first time the microwave-assisted solvothermal synthesis of novel manganese zinc aluminum sulfide using chlorides, sulfates, nitrates and a mixture of chlorides, nitrates, and sulfates in ratio 1:1:1 as cation precursor salts. The influence of microwave reaction temperatures from 100 to 190 °C for 5–60 min were investigated on the crystal structure, morphology, composition, optical, and electrochemical properties. It has been found out that the microwave reaction temperature and time have potential effect on the overall reaction. The optimum temperature and time were found to be 190 °C for 5 min and 150 °C for 20 min for our studies. The obtained powder samples were analyzed using X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared, ultraviolet-visible, cyclic voltammetry, and electrochemical impedance spectroscopy. Structural characterization using X-ray diffraction revealed that the samples synthesized with chlorides, nitrates, and mixtures of the precursor salts were all amorphous while samples synthesized with sulfate precursor salts have a kesterite crystal structure. Raman spectroscopy shows major intense peaks between 326 and 331 cm for all the nanomaterials which could be assigned to the Raman A mode of kesterite CZTS. The morphological features revealed spherical shapes with little agglomeration for all the synthesized materials except for that synthesized with sulfate precursor salts at 190 °C revealing a rod-like morphology with a width of 0.780–1.200 μm, a length of 1.90–2.5 μm and attached to the surface are agglomerated nanospheres. Small-angle X-ray spectroscopy revealed a core-shell shape for most of the nanomaterials with an average particle size between 10 and 100 nm. Electrochemical impedance spectroscopy revealed that electron transfer is faster in the nanomaterials synthesized with the chloride precursor salts at both temperatures studied. The band gap falls within the range of 1.2–1.7 eV. The nanomaterials presented in this study possess the desirable properties for application in photoelectrochemical and solar cells.

Rebuttal on the “comment paper referring to spectroscopic ellipsometry and solar cell performance of Cs‑doped MA0.05FA0.95Pb(I0.98Br0.02)3 triple cation perovskite thin films for solar cell applications)” by M. A. Ebdah

Rebuttal on the “comment paper referring to spectroscopic ellipsometry and solar cell performance of Cs‑doped MA0.05FA0.95Pb(I0.98Br0.02)3 triple cation perovskite thin films for solar cell applications)” by M. A. Ebdah

Comment on “Spectroscopic ellipsometry and solar cell performance of Cs-doped MA0.05FA0.95Pb(I0.98Br0.02)3 triple cation perovskite thin films for solar cell applications” by A. M. El-naggar et al. (Applied Physics A (2022) 128:378)

Comment on “Spectroscopic ellipsometry and solar cell performance of Cs-doped MA0.05FA0.95Pb(I0.98Br0.02)3 triple cation perovskite thin films for solar cell applications” by A. M. El-naggar et al. (Applied Physics A (2022) 128:378)

Towards halide treatment on CdS thin films for solar cell applications: An evolution to ion size impact on segregation and grain boundaries passivation

In this study, an impact of halide ion size on the physical properties of 200 nm thin thermally evaporated CdS films is explored. The ex-situ halide treatment is performed using 0.2 M solutions of halide compounds viz. CdCl2, CdI2, MgF2, MgCl2 and MgI2 separately and subsequently air annealing at 200 °C. A detailed grain growth mechanism in CdS films based upon nature and size of cations and anions to the treatment species is deeply discussed. The recrystallization responsible for modulation in structural, optical, topographical, photoluminescence, electrical, morphological and compositional properties of CdS films is explored via formation of different complexes. The XRD patterns reveal formation of polycrystalline CdS thin films having mixture of cubic (with space group F4̅ 3 m) and hexagonal phases with (220) cubic preferential orientation. Different crystallographic constants are calculated and discussed where the crystallite size is varied from 34 nm to 48 nm with treatment. Surface topographical study indicates that surface roughness is altered with the halide treatment and observed maximum for MgCl2 treated CdS thin films. The pristine and halide treated CdS thin films show Ohmic nature owing to linear current-voltage behavior. Optical study demonstrates that MgI2 treated films have higher transmittance and lower absorbance and energy band gap is measured out in 2.04–2.48 eV range. PL spectra of CdS films reveal a strong red emission band appeared at ∼685 nm corresponding to Sulfur vacancies (VS) and possible A centers (XS+VCd2−)−. FESEM exploration reveals grain growth with probable activation where maximum grain size is obtained for MgF2 treated films. The EDS patterns confirm deposition of CdS films and also integration of F, Cl, I and Mg in the associated treated CdS films. The investigated findings reveal that size of halide ions plays a decisive role in modification of the physical properties of CdS thin films which could be implicated as optical window to CdTe and CIGS based photovoltaic devices.

Silver Alloying in Highly Efficient CuGaSe2 Solar Cells with Different Buffer Layers

This study evaluates the effect of silver alloying, stoichiometry, and deposition temperature of wide‐gap (Ag,Cu)GaSe2 (ACGS) absorber films for solar cell applications. Devices using a standard CdS buffer exhibit a strong anticorrelation between the open‐circuit voltage (VOC) and short‐circuit current density (JSC), with VOC decreasing and JSC increasing toward stoichiometric absorber composition. Increasing the ACGS deposition temperature leads to larger grains and improved JSC, while VOC is not affected. By adding more silver to the absorber (maximum tested [Ag]/([Ag]+[Cu]) [AAC] = 0.4), the widening of the space charge region (SCR) significantly enhances carrier collection. Experimental quantum efficiency spectra can be accurately simulated when assuming a very low diffusion length and perfect collection in the SCR. The highest efficiency of 8.3% (without antireflection coating [ARC]) is reached for an absorber with AAC = 0.4 grown at 600 °C. Replacing CdS by a (Zn,Sn)O buffer with lower electron affinity strongly mitigates interface recombination. Moreover, the VOC–JSC anticorrelation is not evident anymore and the highest efficiency of 11.2% (11.6% w/ARC, VOC = 985 mV, JSC = 18.6 mA cm−2, fill factor = 61.0%) is reached for a close‐stoichiometric ACGS solar cell with AAC = 0.4 processed at 650 °C.

Physical characterization of thermally evaporated Sn–Sb–Se thin films for solar cell applications

Physical characterization of thermally evaporated Sn–Sb–Se thin films for solar cell applications