Fabrication Of Solar Cell Devices Research Articles

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.

THE EFFECT OF TEMPERATURE DEPENDENCE ON TIN PEROVSKITE SOLAR CELL USING SCAPS 1D

Perovskite solar cell (PSC) has become a force to reckon with in the renewable energy community because of its performance and low cost of production. Solar energy is one of the most demanding renewable sources of electricity. Electricity production using photovoltaic technology, not only helps meet the growing demand for energy, but also contributes to mitigate global climate change by reducing dependence on fossil fuels. Simulation is based on a mathematical design that describes the system. Numerical simulation technique of solar cells devices has over the years proven to be a viable tool for observing and understanding the properties of solar cell devices such as the optical, electrical and mechanical properties of complex solar cell devices. It also helps to reduce processing cost and time spent on solar cell device fabrication by providing useful information on how to vary the production parameters to improve the device performance. Solar cell capacitance simulator in one dimension (SCAPS-1D) was used in the modeling and simulation of sandwiched perovskite solar cells (PSCs) with a planar hetero-junction structure in the arrangement of the sandwiched model (FTO/CdS/CH3NH3SnI3/HTM). The energy band diagram, I-V characteristics and other parameters was obtained. The configuration for better performance was then determined, from which further simulations were carried out. When the operating temperature was varied the result shows an overall efficiency of 24.25%, FF of 82.80%, JSC of 30.73mA/cm2, VOC of 0.95V was obtained.

Achieving above 25 % efficiency from FA0.85Cs0.15Pb(I0.85Br0.15)3 perovskite solar cell through harnessing the potential of absorber and charge transport layers

In the present article, better stability and enhanced optical behavior have been reported by using mixed -cation lead mixed - halide perovskites, [FAxCs1−xPb(IxBr1−x)3]x=0.85 as the active layer while SnO2 as electron transport layer and Spiro-OMeTAD has been chosen as hole transport layer. The design of the cell configuration FTO/SnO2/[FAxCs1−xPb(IxBr1−x)3]x=0.85/Spiro-OMeTAD/Au has been developed with the help of SCAPS-1D software. In this work,15.86 % power conversion efficiency has been attained which is approximately equal to experimentally reported result. Further we have analyzed the comparative investigation of various HTL layers in place of Spiro-OMeTAD. Further MoO3 based device parameters like thickness, bandgap and defect density of absorber layer, effect of interface, shunt and series resistance and temperature were tuned and calculated to get their optimum values. Finally, PCE of 25.85 % was attained for the optimized device structure FTO/SnO2/[FAxCs1−xPb(IxBr1−x)3]x=0.85/MoO3/Au. These outcomes could provide an idea for highly efficient solar cell device fabrication.

Effects of alkali-metals (X = Li, Na, K) doping on the electronic, optoelectronic, thermodynamic, and X-ray spectroscopic properties of X–SnI3 halide perovskites

The effect of alkali metals (Li, Na, K) doping at X sites in tin-based X–SnI3 halide perovskite on structural, electronic, phonon, thermodynamic, and X-ray core-level spectroscopic properties was investigated and correlated with optoelectronic efficiency in the development of a stable and environmentally friendly solar technology to replace toxic lead-based perovskite solar cells (PSCs). These calculations were carried out based on the density functional theory approach using the Quantum Espresso software with the generalized gradient approximation (GGA) exchange correlation Perdew Burke Ernzerhorf functional. In addition, the phonon frequency, thermodynamics, and X-ray spectroscopy calculations were completed in Materials Studio using the CASTEP code. Our results reveal that there is a clear correlation between the alkali metal's ionic radius, changes in the lattice structural parameters, and the electronic band gap, such that the lattice constants are 5.940, 5.868, and 5.897 Å and the band gaps are 1.20, 1.14, and 1.10 eV for LiSnI3, NaSnI3, and KSnI3, respectively. The highest lattice constant obtained for LiSnI3, indicates that Li atoms occupied interstitial positions in the perovskite crystal, whereas the direct band gap decreases as cationic size increases, with KSnI3 exhibiting the least band gap. Phonon calculations show that KSnI3 has the lowest negative vibration region in its phonon dispersion plot, indicating dynamic stability. Interestingly, all the structures are found to portray high optical absorption, high extinction coefficient, high polarizability. Additionally, the free energy computation of the perovskites shows a reduction with rising temperature, but enthalpy increases significantly with increasing temperature. Yet, due to phonon lattice vibrations, the heat capacity increased as the temperature rose. Although the XSnI3 (X = Li, Na, and K) perovskites under investigation will perform efficiently as semiconductors and can be used for optoelectronic applications, the KSnl3 perovskite material has the most desirable properties for the fabrication of solar cell devices.

Processing of Lead Halide Perovskite Thin Films Studied with In-Situ Real-Time X-ray Scattering.

Lead halide perovskites have been of paramount interest for solution-processable solar cells, reaching power conversion efficiencies larger than 25%. In this spotlight, we will provide a systematic overview of the influence of different solution-based processing routes of lead halide perovskites on their phase transformation and conversion as revealed through in-situ X-ray-scattering experiments. These experiments were performed in conditions closely mimicking thin film processing methods and conditions used for thin film solar cell device fabrication and therefore provide critical information about the mechanism of the phase transformation, its onset, the kinetics, as well as the emergence and disappearance of various (meso)phases along the way. The measurements capture the overall solidification and conversion process of lead halide perovskite inks into solid films via so-called one-step and two-step spin-coating processes as well as blade coating and hot casting. Processing routes are applied to films based on basic components as well as mixtures of different anions and cations, solvents, and antisolvents, all of which deeply affect the thin film microstructure and morphology of the light-absorbing semiconductor and associated solar cell devices.

Optical properties of new organic-inorganic hybrid perovskites (CH3)2NH2CdCl3 andCH3NH3CdCl3 for solar cell applications

Optical properties are essential in the detailed design of modern perovskite-based solar cells (SCs). In fact, metal halide perovskite semiconductors offer rapid and easy manufacturing of good absorbent layers at low costs with such good optical performances as tunable band gaps, high optical conductivity and also high optical absorption. This is why these semiconductors are ideal candidates for the application of SCs. The two new perovskites (CH3)2NH2CdCl3 and CH3NH3CdCl3 were successfully investigated. Moreover, their optical properties are discussed in the present work. This study would present a suitable way to realize good competitors in efficient solar cell devices thanks to their superior properties including high optical absorbance, small band gaps and high optical conductivity. These findings play a major role in the study of ACdCl3 (A is methylammonium (MA =CH3NH3) and dimethylammonium (DMA =(CH3)2NH2)), optical properties as well as the further fabrication of solar cell devices.

Structural, morphological and optical characterization of chemically deposited Cu2O/PbS thin films

Cu2O/PbS core-shell thin films were synthesized by a chemical bath deposition technique using a reactive mixture containing copper nitrate, lead nitrate, ethylenediaminetetraacetic acid, tetraethyl amine and ammonia solution. Their structural and optical properties are reported in this work. For the elemental composition estimation, Rutherford backscattering spectroscopy (RBS) was performed. From the proton induced scan on the substrate containing the films, all the elements that make up the films were extracted as Cu (34.86%), Pb (1.69%), S (42.31%) and O (65.15%). This is an indication that Cu2O-PbS quaternary thin films were actually deposited on the substrate. The X-ray diffraction analysis showed the formation of multiple peaks indicating that the films possess polycrystalline structure. The scanning electron micrographs of the films depicted particles of different sizes scattered across the film surface. The absorbance, transmittance, absorption coefficient, band gap and extinction coefficient were modified by thermal annealing. Absorbance varies from 1.175 to 1.35 for as-grown, 1.475 to 1.50 for annealed at 150 oC and 1.65 to 2.00 for annealed at 200 oC. The percentage transmittance of 6.75 % was obtained for as-grown sample while those of the annealed samples are 6.0 % and 5.0 % at 150 oC and 200 oC respectively. Maximum absorption coefficient values are 3.48 x 106 m -1 , 3.68 x 106 m -1 and 4.60 x 106 m -1 for As-grown, annealed at 150 oC and 200 oC respectively. The band gap energy value is found to increase from 3.50 eV to 4.00 eV as a result of the increase in annealing temperature from 150 oC – 200 oC. Extinction coefficient values generally varies from 0.75 to 2.70 for as-grown, 0.80 to 2.85 for annealed at 150oC and 0.85 to 3.00 for annealed at 200oC. Based on the wide band gap exhibited by the films, it can be concluded that the films are suitable as window materials in the fabrication of solar cell devices.

Microwave-Assisted Synthesis of Bi2S3 and Sb2S3 Nanoparticles and Their Photoelectrochemical Properties.

Bi2S3 and Sb2S3 nanoparticles were prepared by microwave irradiation of single-source precursor complexes in the presence of ethylene glycol as a coordinating solvent. The as-synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX), photoluminescence (PL), and UV–vis near-infrared (NIR) spectroscopy. Their electrochemical potential was examined in [Fe(CN)]4–/[Fe(CN)]3– by cyclic and square wave voltammetry (CV and SWV) and electrochemical impedance spectroscopy (EIS). GCEBi2S3 and GCESb2S3 exhibit promising electrochemical performance and a higher specific capacitance of about 700–800 F/g in [Fe(CN)]4–/[Fe(CN)]3. Thin films of Bi2S3 and Sb2S3 were successfully incorporated in the fabrication of solar cell devices. The fabricated device using Bi2S3 (under 100 mW/cm2) showed a power conversion efficiency (PCE) of 0.39%, with a Voc of 0.96 V, a Jsc of 0.00228 mA/cm2, and an FF of 44%. In addition, the device exhibits nonlinear current density–voltage characteristics, indicating that Bi2S3 was experiencing a Schottky contact. The Sb2S3-based solar cell device showed no connection in the dark and under illumination. Therefore, no efficiency was recorded for the device using Sb2S3, which indicated the ohmic nature of the film. This might be due to the current leakage caused by poor coverage. The nanoparticles were found to induce similar responses to the conventional semiconductor nanomaterials in relation to photoelectrochemistry. The present study indicates that Bi2S3 and Sb2S3 nanoparticles are promising semiconductor materials for developing optoelectronic and electrochemical devices as the films experience Schottky and Ohmic contacts.

Comparison Study of Metal Oxides (CeO2, CuO, SnO2, CdO, ZnO and TiO2) Decked Few Layered Graphene Nanocomposites for Dye-Sensitized Solar Cells

Recent research is focused on few layered graphene (FLG) with various metal oxides (MOs) as (MOs; CeO2, CuO, SnO2, CdO, ZnO, and TiO2) nanocomposite materials are alternatives to critically important in the fabrication of solar cell devices. In this work, FLG with different MOs nanocomposites were prepared by a novel eco-friendly viable ultrasonic assisted route (UAR). The prepared FLG/MO nanocomposites were performed with various characterization techniques. The crystal and phase compositional were carried out through using X-ray diffraction technique. Surface morphological studies by field emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). Spectroscopic methods were done by Raman and UV-Vis Diffuse reflectance spectra (UV-DRS). The prepared FLG/MO nanocomposites materials were used as a photoanode, in the fabrication of dye sensitized solar cells (DSSCs). Compared to TiO2 nanoparticles (NPs) and other FLG/MO nanocomposites, FLG/TiO2 nanocomposites exhibited superior photovoltaic properties. The obtained results indicate that FLG/TiO2 nanocomposites significantly improved the power conversion efficiency (PCE) of DSSCs. The photovoltaic analyses were performed in a solar simulator with an air mass (AM) of 1.5 G, power density of 100 m W/m2, and current density-voltage (J-V) was investigated using N719 dye.

Theoretical study of α, β unsaturated carbonyl thiophene derivatives to investigate optoelectronic properties toward organic photovoltaics.

Herein theoretical study, we designed sixteen conjugated arylated α,βunsaturated carbonyl thiophene based compounds by using density functional theory (DFT) and time-dependent (TD) density functional theory at modified Perdue Wang density functionalMPW1PW91functional with6-31G (d, p)basis set. Ground and excitedstate geometries, electronic and photophysical characteristics of designed molecules are evaluated by assuming the electron-donating and electron-withdrawing effects of the substituents that are attached to these newly designed molecules. Furthermore, calculation of vibrational spectra, time-dependent effect, isotopic substitution effect and force constant along with thermodynamic quantities are also carried out by using MOPAC (Molecular Orbital Package) with strong implementation of semi empirical Hamiltonians. The results reveal that our designed molecules can be a good candidates for electroluminescent and optoelectronic devices for further fabrication of solar cell devices.

Development of indium (In) doped SnSe thin films for photovoltaic application

The undoped and indium doped SnSe (In-SnSe) thin films were successfully prepared by the two-stage process (sputtering and rapid thermal annealing process). The physical properties of the prepared thin films were investigated. Crystallographic patterns of the undoped and doped SnSe thin films showed the single-phase orthorhombic-SnSe. The diffraction peaks slightly shifted towards the higher diffraction angles as well as Raman peaks also shifted towards higher Raman shift by doping of indium. Morphology of the In-SnSe films changed significantly by changing the indium percentage. The optical bandgap of SnSe and In-SnSe films was varied in between 1.06 eV and 1.50 eV, and the electrical properties of In-SnSe films were significantly changed with dopant concentration. The obtained physical properties of In-SnSe thin films are suitable for solar cell device fabrication.

Perovskite Single-Crystal Thin Film Devices Using Lithography Assisted Epitaxy

Strain engineering is an emerging technique to physically manipulate and enhance semiconductor device performance. Chen et al. recently combined strain engineering with halide perovskites, demonstrating a novel approach toward improvement in optoelectronic properties.

Compositional study of mixed halide perovskite films CH3NH3Pb(I1-xBrx)3 and CH3NH3Pb(I1-xClx)3 prepared by close space sublimation

The preparation and characterization of homogeneous and crystalline films of the perovskites CH3NH3Pb(I1-xBrx)3 and CH3NH3Pb(I1-xClx)3 obtained by the close space sublimation method are reported. Perovskites with a mixture of halides were prepared by the sublimation of the methylamine halide CH3NH3Br or CH3NH3Cl over predeposited lead iodide films at different sublimation times to modify the I:Br or I:Cl ratio. The perovskite films CH3NH3Pb(I1-xBrx)3 showed a bandgap shift. For CH3NH3Pb(I1-xClx)3 films with sublimation times of 2.5−40 min, no changes were observed; however, for longer times, the absorption spectrum became similar to that of the CH3NH3PbCl3 material. In this study, the mixed halide perovskites CH3NH3Pb(I1-xBrx)3 and CH3NH3Pb(I1-xClx)3 were prepared with just two precursors, instead of the common approaches that use PbI2, PbBr2, MAI and MABr, as well as PbI2, PbCl2, MAI and MACl. Perovskite layers were applied for the fabrication of solar cell devices, and efficiencies of 9.9 % and 10.2 % were achieved for CH3NH3Pb(I1-xBrx)3 and CH3NH3Pb(I1-xClx)3, respectively. In addition, perovskite LEDs were also prepared. While the well-known green emission at 533 nm was observed for CH3NH3Pb(I1-xBrx)3, for the CH3NH3Pb(I1-xClx)3 based-devices, a broad emission spectrum similar to a warm white emission was obtained. Therefore, a new approach through the sublimation method is reported to fabricate solar cells and LEDs where the main parameter to regard is the sublimation time.

Incorporating quantum dots for high efficiency and stable perovskite photovoltaics

Enhancing bulk perovskite photovoltaics by integrating perovskites and metal chalcogenide quantum dots.

Tuning Optoelectronic Properties of Dithienopyrrole Donor Molecules for Organic Solar Cells

Theoretical analysis of physical properties of organic solar cells (OSCs) are important in order to reveal the correlation between power conversion efficiencies (PCE), structure and properties. Five new A‒D‒A type small molecules M1, M2, M3, M4, and M5 were designed by using dithienopyrrole (DTP) as electron rich donor unit with different types of π-spacers and end capped acceptor units. Functional MPW1PW91/6-31G(d,p) level of theory was used to optimize the geometry of all molecules. For excited state calculation TD-MPW1PW91/6-31G(d,p) level of theory was used. The geometries, electronic structures, dipole moment, open circuit voltage, reorganization energies and charge transport properties of designed molecules (M1 $$ - $$ M5) have been scrutinized comparing with the reported compound R. The results revealed that the HOMO energy levels of molecules M1, M2, M3, and M5 were lower while M4 was of high energy level thus facilitate the donation of electron as compared to references molecule R. While LUMO energy level of all the molecules were slightly high energy due electron withdrawing effects of spacer and acceptor moiety. Highest energy gap of HOMO–LUMO was observed in M1 which was 2.48 eV and M3 showed low energy gap (2.11 eV) as compared to other designed molecules. All molecules showed low values for λe, so they have high rate of electron transfer as compared to R. All designed molecules exhibited higher value of dipole moment as compared to reference molecule R except M1. Higher value of dipole moment of donor molecules contrary to reference means good solubility towards organic solvents which is beneficial for further solar cell device fabrication. All designed molecules show higher Voc values except M4 which has comparable Voc with respect to reference molecule R. In short, choice of appropriate electron withdrawing and donating groups is very important for improving power conversion efficiencies of OSCs.

Development of Organic Dye-Based Molecular Materials for Use in Fullerene-Free Organic Solar Cells.

This personal account describes the pursuit of non-fullerene acceptors designed from simple and accessible organic pi-conjugated building blocks and assembled through efficient direct (hetero)arylation cross-coupling protocols. Initial materials development focused on isoindigo and diketopyrrolopyrrole organic dyes flanked by imide-based terminal acceptors. Efficiencies in solution-processed organic solar cells were modest but highlighted the potential of the material design. Materials performance was improved through structural engineering to pair perylene diimide with these organic dyes. Optimization of active layer processing and solar cell device fabrication identified the perylene diimide flanked diketopyrrolopyrrole structure as the best framework, with fullerene-free organic solar cells achieving power conversion efficiencies above 6 %. This material has met our criteria for a simple wide band gap fullerene alternative for pairing with a range of donor polymers.

Synthesis of new 2-((5-(4-alkyl-4H-dithieno[3,2-b:2′,3′-d]pyrrol-2-yl)thiophen-2-yl)methylene)malononitrile: Dopant free hole transporting materials for perovskite solar cells with high power conversion efficiency

Two multi-chromophoric hybrid small molecule organic materials (ICTH1 and ICTH2) with D-π-A architecture were synthesized and their applicability as hole transporting materials for perovskite solar cells was explored. The strong electron-donating dithieno[3,2-b:2′,3′-d]pyrrole (D) and electron-accepting dicyanovinylene (A) moieties impart high intramolecular charge transfer nature to these materials and eliminates the need of additives or dopants during the fabrication of solar cell devices. Both ICTH1 and ICTH2 have deep HOMO level compared to spiro-OMeTAD and is advantageous to produce high Voc values. Hole transporting ability of ICTH1 and ICTH2 is ascertained by fabricating OFETs. Compared to spiro-OMeTAD, both ICTH1 and ICTH2 showed one order higher hole mobility. Perovskite solar cells (PSCs) with conventional architecture of FTO/Meso-TiO2/MAPbI3/HTM/Ag are fabricated using ICTH1 and ICTH2 as hole transporting and the simplest MAPbI3 as perovskite materials. PSCs with ICTH2 and ICTH1 HTMs, showed power conversion efficiency (PCE) of 18.75% and 17.91% with active area of 2.04 and 2.18 cm2, respectively. Under the similar conditions, PSCs with spiro-OMeTAD HTM showed 14.74% PCE with active area of 1.84 cm2. Even after 40 days, solar cell devices with ICTH2 showed superior performance (PCE of 16.08%) over the spiro-OMeTAD devices (PCE of 6.77%). Apart from the superior device performance, other prominent factors like synthetic simplicity, dopant-free nature and low production cost make ICTH1 and ICTH2 as potential alternatives to spiro-OMeTAD for using as HTM in PSCs.

Electrospun Conjugated Polymer/Fullerene Hybrid Fibers: Photoactive Blends, Conductivity through Tunneling-AFM, Light Scattering, and Perspective for Their Use in Bulk-Heterojunction Organic Solar Cells.

Hybrid conjugated polymer/fullerene filaments based on MEH-PPV/PVP/PCBM were prepared by electrospinning, and their properties were assessed by scanning electron, atomic and lateral-force, tunneling, and confocal microscopies, as well as by attenuated-total-reflection Fourier transform infrared spectroscopy, photoluminescence quantum yield, and spatially resolved fluorescence. Highlighted features include the ribbon shape of the realized fibers and the persistence of a network serving as a template for heterogeneous active layers in solar cell devices. A set of favorable characteristics is evidenced in this way in terms of homogeneous charge-transport behavior and formation of effective interfaces for diffusion and dissociation of photogenerated excitons. The interaction of the organic filaments with light, exhibiting specific light-scattering properties of the nanofibrous mat, might also contribute to spreading incident radiation across the active layers, thus potentially enhancing photovoltaic performance. This method might be applied to other electron donor–electron acceptor material systems for the fabrication of solar cell devices enhanced by nanofibrillar morphologies embedding conjugated polymers and fullerene compounds.

Effect of Surface Passivation on CdxNi1-xS Thin Films Embedded with Nickel Nanoparticles

Certain treatments done to binary CdS , such as incorporating Ni onto CdS produces ternary thin films may cause major optical parameters that have a number of applications including for solar cell device fabrication. In this paper, we report on the effect of surface passivation on the band gap and other related optical properties of CdNiS thin films. Thin films for Cd x Ni 1-x S were prepared on glass substrates by chemical solution method. Effects of surface passivation and variation of the volume of nickel ions on the optical properties CdS hence obtaining Cd x Ni 1-x S thin films was investigated. It was observed that the thin films hard an average Transmittance above 68 %, with reflectance below 25 % across UV-VIS-NIR region. A plot of ( αhν ) 2 versus hν gave energy band gap between 2.55–3.49 eV for as-grown samples and 2.82–3.50 eV for annealed samples. The passivated samples had band gap energy values within the range 2.85–3.12 eV. It was concluded that an increase in concentration of Cd 2+ and Ni 2+ ions in the reaction led to an increase the band gap while optical conductivity ranged between 3.78x10 11 –2.40x10 12 S -1 .

(Invited) Materials Design By Atmospheric Pressure Plasmas for Solar Energy Harvesting

Atmospheric pressure plasmas (APP) have demonstrated exceptional versatility to synthesize and modify a very wide range of materials with varying morphologies, sizes and compositions [1-3]. These include semiconducting, oxide and metal nanoparticles, nanostructured films and ultra-small quantum confined nanostructures. APPs have key features which would make the corresponding processes highly desirable for large scale manufacturing. In recent years we have therefore focused our efforts in developing ad-hoc APP processes with in mind two main objectives. On one side we have developed processes that could be integrated in the fabrication of application devices so that we could demonstrate direct applicability of APPs to relevant device fabrication steps. In particular we have developed APP-based strategies for solar cell device fabrication [4]. At the same time we have tried to work bottom-up, whereby our materials synthesis approach was dictated by desired materials functionalities. Here we will exemplify our efforts with a range of semiconducting nanoparticles and metal oxides to include Cu-, Zn-, Ni-, Mo- and Co-oxides. We will show different synthesis mechanisms and how specific properties such as bandgap, quantum confinement and plasmon resonance can be tailored guided by our materials needs. We will then demonstrate the materials functionalities within photovoltaic devices. [1] Journal of Physics D: Applied Physics 43 (2010) 415402 [2] Chemical Physics Letters 478 (2009) 224 [3] Applied Physics Letters 104 (2014) 163103 [4] Plasma Process. Polym. 13 (2016) 70