Absorber Layer In Solar Cells Research Articles

Plasmon assisted optical absorption and reduced charge recombination for improved device performance in polymer solar cell

Silver and Calcium (Ag:Ca) bi-metallic nano-partices have been successfully synthesized using a chemical reduction processes. The nano-partices were intended to be used in the solar absorber layer of thin film organic solar cell (TFOSC) to assist in improving optical absorption and charge transport processes in polymers blend medium. The nanocomposite (Ag:Ca) is expected to exhibit local surface plasmon resonance (LSPR) and far-field scattering from the interaction with the incident photons. The absorber layer of TFOSC, in this investigation, is prepared from the mixture of poly-(3-hexylthiophene) (P3HT): [6,6]-phenyl C61 butyric acid methyl ester (PC61BM). Devices were fabricated at various concentration of metal nano-particles in the solar absorber layer, as 1%, 3%, and 5% by weight, to be able to determine the optimum concentration of the dopant. Hence, the experimental evidences clearly showed that performance of the solar cell is dependent on the concertation of the metal nano-particles. Consequently, the power conversion efficiency (PCE) value has increased by 75% with a remarkable improvement in device fill factor of 53.4% at an optimum doping level of 3%. The optical and morphological properties of the synthesized nano-particles are well presented and discussed in terms of the data collected using transmission and scanning electron microscopy (TEM & SEM) and other complimentary methods.

Studies on DC sputtered cuprous oxide thin films for solar cell absorber layers

Cuprous oxide (Cu2O) thin films are prepared on corning glass substrates by metallic sputtering of copper under an oxygen atmosphere. The flow rate of oxygen is varied from 4 SCCM to 7 SCCM and the properties of as-deposited films are reported in this work. The structural, phase confirmation, morphology, elemental composition, bonding, and optical characteristics of Cu2O thin films is studied using various characterization tools such as X-ray Diffraction (XRD), Raman Spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) and UV–Visible Spectrometer. It is perceived that the flow rate plays a vital role in obtaining the single-phase Cu2O thin films. The bandgap of the deposited thin films is measured and is in the range of 2.29–2.37 eV, making it suitable for thin-film solar cell applications.

Low temperature assisted phase transitions in thermally evaporated Cu2Se/Ga3Se2/In3Se2 multilayer thin film structure: Raman signatures of a pristine chalcopyrite CuInxGa1-xSe2 structure

Copper Indium Gallium Selenide (CIGS) thin film solar cell absorber layers are fabricated by the conventional co-evaporation of metal stack precursors followed by a selenization process at a high-temperature range. The article deals with an alternative approach to fabricate the CIGS layer by sequential evaporation of metal selenides followed by a low-temperature treatment (250 °C) during pre-and post-deposition processes. Our post annealing treatment on substrate heat treated film reported a first-ever pristine CuIn0.7Ga0.3Se2 thin film structure without selenization was reported at a very low temperature. A better microstructure with an enhanced grain growth, preferential (112) plane orientation, and Raman signatures of pristine chalcopyrite without a secondary Cu2-xSe phase at the surface was observed. Electron microscopy studies affirm the polycrystalline nature of film structure. Optical analyses have shown near-optimum values as of standard absorber layers. Crucial optical parameters such as refractive index, static and high-frequency dielectric constants were estimated by different relations. The values are concurrent with the semiconductor scale. These features in a low-temperature range optimistically land them as promising candidates in flexible electronics.

Cs2TiBr Solar Cell Performance Enhancement by Different Absorber Layer Thickness

Cs2TiBr6 is a promising material as an Absorber layer of Solar cell. Further studies showed that this compound is more stable, and possess an appropriate electrical and optical properties. The compound of (FTO/V2O5/Cs2TiBr6/CdTe) is simulated for the first time in this work by using the Solar Cell Capacitance Simulator (SCAPS-1D) program and the obtained transformation efficiency (η) was (10.09) with (0.5µm) of (Cs2TiBr6) thickness. The effect of (Cs2TiBr6) thickness was studied in this paper used different variations of absorber layer thickness (0.5 – 4.0 μm). Solar cell enhanced by absorber layer thickness showed (18.17 mA/cm2, 0.924V, and 86.58%) (Jsc, Voc, FF) respectively which led to increase of transformation efficiency (η) from (10.09 % to 14.55%).

Opto-Magnetic and Morphological Properties of the Quaternary CZCr+2TS Semiconductor

Recently, Cu2ZnSnS4 (CZTS) chalcogenide has been given extra attention in CZTS thin-film solar cells. In order to enhance the conversion efficiency of CZTS thin-film solar cells, the physical properties of CZTS semiconductor have been improved by incorporating Cr elements into the CZTS semiconductor using the solvothermal method. The experimental results showed that the Cr[Formula: see text] ion had stronger hybridization and are more effective on energy storage than Zn[Formula: see text] ion. XRD pattern revealed that the crystal structure of CCrTS compound has high crystallinity and low distortion. Raman analysis indicated the structural transition from kesterite CZTS to stannite CCrTS occurred in the multicomponent CZCrTS samples with Cr content ([Formula: see text]) in the range of 0.75–1. In addition, VSM and UV–Vis absorption spectrum showed the CCrTS compound had a new opto-magnetic property and exhibit a strong ferromagnetic ordering at room temperature. Where the magnetic energy resulted from incorporating Cr[Formula: see text] ion in the Cu2ZnSnS4 has been stored and distributed in abroad absorption band in UV–vis ranges And Also, led to a decrease in the direct bandgap in the ranges of 1.54–1.25[Formula: see text]eV. FE-SEM showed that by replacing Cr[Formula: see text] ion with Zn[Formula: see text] ion, the particle size was decreased as a result of converting the applied strain from compressive strain to tensile strain in the CZCr[Formula: see text]TS resulting in decreasing the unit cell volume and the crystal size. This shows that incorporating Cr[Formula: see text] ions into CZTS compound may be well suitable for fabricating it as an absorber layer in CZTS thin-film solar cells.

Investigation on the Stability and Efficiency of MAPbI3 and MASnI3 Thin Films for Solar Cells

Hybrid organic–inorganic halides are considered as outstanding materials when used as the absorber layer in perovskite solar cells (PSCs) because of its efficiency, relieve of fabrication and low‐cost materials. However, the content of lead (Pb) in the material may origin a dramatic after effect on human's health caused by its toxicity. Here, we investigate replacing the lead in MAPbI3 with tin (Sn) to show its influence on the growth of the film nucleation and stability of the solar device based on MASnI3. By analysing the manufactured perovskite films by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), UV–visible absorption, photoluminescence (PL) and atomic force microscopy (AFM), the properties of the thin films when lead is replaced by tin are reported. The simulation run for the case of MAPbI3 is reported, where Voc = 0.856 V, Jsc = 25.65 mA cm−2, FF = 86.09%, and ETA = 18.91%, and for MASnI3, Voc = 0.887 V, Jsc = 14.02 mA cm−2, FF = 83.72%, and ETA = 10.42%. In perovskite‐based devices using MASnI3 as absorber, it was found to be more stable despite of its lower efficiency, which could be improved by enhancing the bandgap alignment of MaSnI3. The results of this paper also allow the development of a new, reliable production system for PSCs.

Impact of different parameters on the performance of GaAs solar cell using PC1D simulation

In this work, GaAs solar cell has been analyzed by using PC1D simulation software. Optimization of thickness and doping concentration of emitter and absorber layer of solar cell is done. Effect of front and rear surface recombination velocity is analyzed in this work. When surface recombination velocity increases, the value of efficiency decreases due to increase in recombination process. The optimum value of surface recombination velocity are Sn = Sp = 102 cm/s. Front surface reflection is minimized by the use of TiO2 single layer ARC and double layer LiF/HfO2 ARC. Increase in efficiency around 2.71% is achieved as compared to cell without ARC after applying anti-reflection coating of optimum thickness. Simulation results shows GaAs solar cell with efficiency of 26.68%.

Fabrication of the Cu2ZnSnS4 Thin Film Solar Cell via a Photo-Sintering Technique

Alternative photo-sintering techniques for thermal annealing processes are used to improve the morphology, layer properties, and enhance solar cell performance. The fast, nontoxic, low cost, and environmentally friendly characteristics of Cu2ZnSnS4 have led to its consideration as an alternative potential absorber layer in copper indium gallium diselenide thin film solar cells. This work investigates the photo-sintering process for the absorber layer of Cu2ZnSnS4 solar cells. A Cu2ZnSnS4 layer was grown by hot-injection and screen-printing techniques, and the characteristics of the photo-sintered Cu2ZnSnS4 layer were evaluated by X-ray Diffraction, Raman spectroscopy, Energy dispersive X-ray analysis, Ultraviolet-visible spectroscopy, and field emission scanning electron microscopes. Overall, the optimal composition was Cu-poor and Zn-rich, without a secondary phase, estimated optical band-gap energy of approximately 1.6 eV, and enhanced morphology and kesterite crystallization. Using an intensity pulse light technique to the CZTS layer, fabrication of the solar cell device demonstrated successfully, and the efficiency of 1.01% was achieved at 2.96 J/cm2.

Pre-deposited alkali (Li, Na, K) chlorides layer for effective doping of CuInSSe thin films as absorber layer in solar cells

We introduce an effective method for copper indium sulfide selenide (CISSe) doping with different alkali metals (Li, Na and K) based on a pre-deposited alkali chloride layer. A simple and fast spray method is used for pre-deposition of alkali chloride layer (LiCl, NaCl, KCl) on substrate surface before spray pyrolysis deposition of copper indium disulfide CuInS2 (CIS) films followed by selenization. The different properties of alkali-doped CISSe films by the alkali chloride pre-deposition (ACPD) method were compared to the post-deposition treatment (PDT) method. Based on FESEM images, a highly compact film with large grains can be obtained for CISSe films doped with K(∼0.72 μm) and Na (∼0.56 μm) by the ACPD method that is considerably higher than un-doped films (∼0.47 μm). While for the PDT method, grain size decreased after the doping process. UV–Vis analysis showed that alkali atoms with larger size result in more band gap widening of CISSe film. According to Mott-Schottky results, all films are p-type but doping density is dependent on the doping method. CISSe films doped by the ACPD method show smaller doping density, the smallest value of carrier concentration is 3.1 × 1017 cm−3 for K-doped CISSe film. All CISSe doped films by ACPD method show higher mobility compared to CISSe film doped by PDT method and larger atom results in higher mobility. The numerical modeling work using SCAPS software showed that solar device with ACPD K-doped CISSe film as absorber layer results in higher efficiency compared to Li, Na- doped and undoped CISSe films.

First-principles calculations to investigate the structural, electronic and optical properties of lead-free double perovskites Rb2SeI6 and K2SeI6

In this work, we have studied in detail the structural, electronic and optical properties of lead-free double perovskites Rb2SeI6 and K2SeI6 based on first-principles calculations. Their negative binding energy (Eb) and formation energy (Ef) ensure the stability of the studied materials. Our calculations give band gap values of Rb2SeI6 and K2SeI6 to be 1.51 eV and 1.45 eV, respectively. This illustrates that the two perovskite compounds belong to indirect band gap semiconductors, and are suitable for photosensitive materials of solar cells. For both Rb2SeI6 and K2SeI6, the valence band maximum (VBM) are dominated by the I-p orbitals, and their conduction band minimum (CBM) are mainly contributed from the I-p orbitals and the Se-p orbitals. The results indicate that the effective mass of electrons and holes in Rb2SeI6 and K2SeI6 is very small, and therefore they are favorable for carrier transport. Moreover, the optical parameters display that Rb2SeI6 and K2SeI6 have significant light absorption properties, especially in the visible light range. Due to the suitable band gap values and excellent light absorption, Rb2SeI6 and K2SeI6 have great application potential in the absorption layer of solar cells.

Numerical simulation of novel lead-free Cs3Sb2Br9 absorber-based highly efficient perovskite solar cell

In this paper, a novel Cs 3 Sb 2 Br 9 perovskite is presented for the absorber layer of perovskite solar cells (PSC). A planar structure as ITO/TiO 2 /Absorber/Spiro-OMeTAD/Au with Cs 3 Sb 2 Br 9 as a light harvesting material is numerically simulated using SCAPS-1D simulation software. Initially, the optimization is performed on the various material parameters of absorber layer such as thickness, bulk defect density, relative permittivity and bandgap. The obtained optimal values for these parameters are 1000 nm, 1 × 10 12 cm −3 , 10, and 2.0 eV, respectively. Finally, the proposed PSC structure with optimized absorber layer is achieved the maximum power conversion efficiency (PCE) of 15.69% whereas V OC as 1.31 V, J SC as 13.67 mA/cm 2 , FF as 87.61%, and QE of ∼100% at 390 nm wavelength near the visible range of solar spectrum. The obtained results of numerical simulations with Cs 3 Sb 2 Br 9 as absorber layer endorse the novel proposed PSC material as the main body of PSC and opens a better route towards the development of a cost effective, highly efficient (Pb) lead-free and environment friendly PSC. • A novel Cs 3 Sb 2 Br 9 absorber layer material is proposed for design of high efficiency lead-free perovskite solar cell. • Numerical analysis and optimization of novel absorber in proposed PSC structure is performed using SCAPS-1D to investigate the effect of bulk defect density, absorber thickness, energy bandgap and permittivity variations on PSC parameters. • A planar structure consisting of charge transport materials TiO 2 and Spiro-OMeTAD used as ETL and HTL, is simulated for the analysis. • The proposed PSC is promising and may offer the PCE of 15.69% with V OC of 1.31 V , J SC of 13.67 mA/cm 2 and FF of 86.78%.

Numerical Modelling Analysis for Carrier Concentration Level Optimization of CdTe Heterojunction Thin Film–Based Solar Cell with Different Non–Toxic Metal Chalcogenide Buffer Layers Replacements: Using SCAPS–1D Software

Cadmium telluride (CdTe), a metallic dichalcogenide material, was utilized as an absorber layer for thin film–based solar cells with appropriate configurations and the SCAPS–1D structures program was used to evaluate the results. In both known and developing thin film photovoltaic systems, a CdS thin–film buffer layer is frequently employed as a traditional n–type heterojunction partner. In this study, numerical simulation was used to determine a suitable non–toxic material for the buffer layer that can be used instead of CdS, among various types of buffer layers (ZnSe, ZnO, ZnS and In2S3) and carrier concentrations for the absorber layer (NA) and buffer layer (ND) were varied to determine the optimal simulation parameters. Carrier concentrations (NA from 2 × 1012 cm−3 to 2 × 1017 cm−3 and ND from 1 × 1016 cm−3 to 1 × 1022 cm−3) differed. The results showed that the use of CdS as a buffer–layer–based CdTe absorber layer for solar cell had the highest efficiency (%) of 17.43%. Furthermore, high conversion efficiencies of 17.42% and 16.27% were for the ZnSe and ZnO-based buffer layers, respectively. As a result, ZnO and ZnSe are potential candidates for replacing the CdS buffer layer in thin–film solar cells. Here, the absorber (CdTe) and buffer (ZnSe) layers were chosen to improve the efficiency by finding the optimal density of the carrier concentration (acceptor and donor). The simulation findings above provide helpful recommendations for fabricating high–efficiency metal oxide–based solar cells in the lab.

Highly Selective Cu Staining of Sulfur-Containing Polymers Facilitates 3D Nanomorphology Reconstruction of Polymer:Fullerene Blends in Organic Solar Cells by FIB-SEM Tomography.

The distinction of different organic materials in phase mixtures is hampered in electron microscopy because electron scattering does not strongly differ in carbon-based materials that mainly consist of light elements. A successful strategy for contrast enhancement is selective staining where one phase of a material mixture is labeled by heavier elements, but suitable staining agents are not available for all organic materials. This is also the case for bulk-heterojunction (BHJ) absorber layers of organic solar cells, which consist of interpenetrating networks of donor and acceptor domains. The domain structure strongly influences the power conversion efficiency, and nanomorphology optimization often requires real-space information on the sizes and interconnectivity of domains with nanometer resolution. In this work, we have developed an efficient approach to selectively stain sulfur-containing polymers by homogeneous Cu infiltration, which generates strong material contrast in scanning (transmission) electron microscopy (S(T)EM) images of polymer:fullerene BHJ layers. Cross-section lamellae of BHJ layers are prepared for STEM by focused-ion-beam milling and are attached to a Cu lift-out grid as a copper source. After thermal treatment at 200 °C for 3 h in air, sulfur-containing polymers are homogeneously infiltrated by Cu, while the fullerenes are not affected. Selective Cu staining is applied to map the phase distribution in PTB7:PC71BM BHJ layers fabricated with different processing additives to tailor the nanomorphology. The strong contrast between polymer and fullerene domains is the prerequisite for the three-dimensional reconstruction of the domain structure by focused-ion-beam/scanning-electron-microscopy tomography.

Substrate temperature-dependent diffusion from CdS/ZnO:Al layer into the absorber layer in Cu(In, Ga)Se2 solar cell during the deposition of ZnO:Al window layer

Substrate temperature-dependent diffusion from CdS/ZnO:Al layer into the absorber layer in Cu(In, Ga)Se2 solar cell during the deposition of ZnO:Al window layer

Polyvinylpyrrolidone capped electrospun CH3NH3PbCl3 perovskite film as the electron transport layer in perovskite solar cell application

Due to the inherent moisture instability problem of hybrid lead halide perovskites, polymer additives have to turn out to be a significant research area to enhance the moisture stability of these materials. It has been found that polymer engineering on the absorber layer of solar cells significantly improves chemical stability and overall device performance. This work reports the fabrication of pristine and polyvinylpyrrolidone (PVP) polymer capped methylammonium lead chloride (CH3NH3PbCl3) perovskite film via the electrospinning method. A structural study using an X-ray diffractometer shows a sharp fall in average crystallite size from 66.05 nm to 39.69 nm when PVP is used in the synthesis procedure. A similar trend is also seen in the microscopic analysis, which depicts that the particle size has decreased for PVP added CH3NH3PbCl3 perovskite film in comparison to CH3NH3PbCl3 pristine film. The surface coverage and uniformity of the film is much more in the presence of PVP. It has been noted from energy dispersive X-ray analysis that the oxygen content is ∼16% more in the pure film, i.e. PVP hinders the effect of moisture in perovskite film, which is the prime objective of this work. Moreover, the optical properties have been analyzed using diffuse reflectance mode of UV–Vis-NIR spectroscope. Finally, the use of CH3NH3PbCl3 as the electron transport layer has been demonstrated in Glass/FTO/CH3NH3PbCl3/CH3NH3SnI3/Spiro-OMeTAD/Au structured perovskite solar cell using the SCAPS-1D simulator. The above-mentioned cell exhibits a power conversion efficiency (PCE) of 21.65%, fill factor (FF) of 72.21%, 32.44 mA/cm2 of short circuit current density (Jsc), and 0.924 V open-circuit voltage (Voc).

Enhancing the stability and crystallinity of CsPbIBr2 through antisolvent engineering

All inorganic lead-based perovskites containing bromine-iodine alloys, such as CsPbIBr2, have arisen as one of the most attractive candidates for absorber layers in solar cells. That said, there remains a large gap when it comes to film and crystal quality between the inorganic and hybrid perovskites. In this work, antisolvent engineering is employed as a simple and reproducible method for improving CsPbIBr2 thin films. We found that both the antisolvent used and the conditions under which it was applied have a measurable impact on both the quality and stability of the final product. We arrived at this conclusion by characterising the samples using scanning electron microscopy, X-ray diffraction, UV–visible and photoluminescence measurements, as well as employing a novel system to quantify stability. Our findings, and the application of our novel method for quantifying stability, demonstrate the ability to significantly enhance CsPbIBr2 samples, produced via a static one-step spin coating method, by applying isopropanol 10 s after commencing the spin programme. The antisolvent quenched CsPbIBr2 films demonstrate both improved crystallinity and an extended lifespan.

Effective energy harvesting in thin film organic solar cells using Ni:Zn as bimetallic nanoparticles

This article explores the effect of bimetallic plasmonic nanocomposites in the solar absorber layers of thin-film organic solar cells (TFOSCs) for possible improvement in harvesting solar energy. To achieve this goal, a new nanocomposite composed of Nickel and Zinc (Ni: Zn) was successfully synthesized by the use of a chemical reduction processes. The effect of bimetallic nanocomposites was studied using a photoactive medium, which comprises of poly-(3-hexylthiophene) (P3HT) [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) blend and doped with Ni:Zn at different concentrations. Consequently, an improved power conversion efficiency value up to 4.78% was found at 1% Ni:Zn bimetallic concentration by weight compared to reference solar cell. This is a clear indication of the influence of Ni:Zn bimetallic nanoparticles on the performance of TFOSC. These effects have been realized by the occurrence of local surface plasmon resonance (LSPR) phenomenon caused by Ni: Zn nanoparticles in polymer medium.

On the spectral response of interdiffused quantum dot ensembles embedded in the intrinsic region of InGaAs/GaAs quantum dot solar cells

Semiconductor nanostructures, such as, quantum dots (QDs), embedded in the absorber layer of solar cells (SCs) are high priority research topics in the field of QDSCs. The dot size distribution is one of the critical factors governing the spectral response (SR) of these embedded nanostructures. The dot aspect ratio (AR) may serve as a useful and accurate parameter for analyzing such size distribution, as it helps in addressing the cumulative variation of dot size in the lateral, as well as growth direction. Furthermore, due to interdiffusion, the sharp heterointerface between the dot material and surrounding matrix is likely to get diluted. The incorporation of such a phenomenon in the theoretical model of QDSC seems to be demanding for accurately evaluating the performance of fabricated cells. Based on the above, this work is an effort to propose a unified analytical model for the SR of QD ensembles embedded in the intrinsic region of InGaAs/GaAs p-i-n QDSCs, taking into account the variation of dot AR and changes in the potential profile due to interdiffusion, which, for the first time, being analyzed in a common platform. Through our proposed model, we have also investigated the effects of dot AR, size deviation and extent of interdiffusion on the SR and photocurrent density of the cell structure under consideration. At each stage of our computation, we have compared the performance of interdiffused dots with the conventional modeling approach representing as-grown structures, to uncover suitable explanations justifying the degraded performance of fabricated QDSCs as compared to their other competitors.

Preparation of Cu2CdxZn1−xSnS4 thin films by nanoparticle ink method

Because of their excellent optical and electrical properties, Cu2ZnSnS4 (CZTS) thin films have been considered as a potential absorber layer for solar cells. However, CZTS suffers from some problems, such as secondary phases, antisite defects, and band tailing issues. Introducing Cd into CZTS to form Cu2CdxZn1−xSnS4 (CCZTS) is an effective method for alleviating the limitations of CZTS. In this study, the nanoparticle ink method was used to fabricate CCZTS thin films, and the effect of Cd content on the properties of CCZTS thin films was studied. The results showed that the as-prepared thin films had high purity, good crystallinity and photocurrent response. The photosensitivity and power conversion efficiency increased at first and then decreased with increasing Cd content. Due to the relatively excellent crystallization and photoresponse characteristics, the highest conversion efficiency of 0.72% was obtained when x = 0.3.

Numerical Exploration of Lead-Free Inorganic Perovskite Cs2TiBr6 Solar Cell

As a third-generation solar cell technology, perovskite solar cells are facing booming growth. However, typical perovskite solar cells have two critical challenges on the road to actual commercialization: toxicity and stability. Finding high-performance lead-free inorganic perovskites to replace conventional lead-based perovskites is an effective way to overcome both challenges. A lead-free inorganic perovskite Cs2TiBr6 has been demonstrated that possesses the impressive photoelectric property of direct bandgap and excellent environmental stability from recent experimental results. In addition, Cs2TiBr6 has been used as the absorber layer in a perovskite solar cell with an efficiency of 3.28%, which is lower than the efficiencies of typical lead-based perovskite cells. Therefore, it is significant to further explore the structure of Cs2TiBr6 solar cell for improving its power conversion efficiency. This work proposes a solar cell with the FTO/ETL/Cs2TiBr6/HTL/Au structure, then selects the most suitable hole and electron transport materials among some typical transport materials. Moreover, we optimize the absorber layer thickness. The optimized solar cell with the FTO/SnO2/Cs2TiBr6/PEDOT:PSS/Au structure possesses an efficiency of 7.92%. Our results show that lead-free inorganic perovskite Cs2TiBr6 used as an absorber in the solar cell has great potential. In addition, appropriate hole transport material, electron transport material, and absorber layer thickness can improve its performance.