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1.
In this report, Ag nanoparticles were fabricated using the single-step glancing angle deposition (SS-GLAD) technique upon In2O3/TiO2 thin film. Afterward, a detailed analysis was done for the two samples such as In2O3/TiO2 thin film and In2O3/TiO2 thin film/Ag nanoparticles, to inspect the field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), ultraviolet (UV) spectroscopy, and electrical properties. The reduction in bandgap energy for the samples of In2O3/TiO2 thin film/Ag nanoparticles (~4.16 eV) in comparison with the In2O3/TiO2 thin film (~4.28 eV) was due to trapped e–h recombination at the oxygen vacancies and electron transmission of Ag to the conduction band of the In2O3/TiO2 thin films. Moreover, under irradiation of photons Ag nanoparticles generated inorganic Ag–O compound attributable to the localized surface plasmon resonance (LSPR). Also, a?~90% high transmittance,?~60% and?~25% low reflectance in UV and visible region, fill factor (FF) of 53%, as well as power conversion efficiency (PCE) of 15.12% was observed for In2O3/TiO2 thin film/Ag nanoparticles than the In2O3/TiO2 thin film. Therefore, the use of Ag nanoparticles textured In2O3/TiO2 thin film–based device is a promising approach for the forthcoming photovoltaic applications. 相似文献
2.
We investigated the effect of SiO 2 spacer layer thickness between the textured silicon surface and silver nanoparticles (Ag NPs) on solar cell performance using quantum efficiency analysis. Separation of Ag NPs from high index silicon with SiO 2 layer led to modified absorption and scattering cross-sections due to graded refractive index medium. The forward scattering from Ag NPs is very sensitive to SiO 2 layer thickness in plasmonic silicon cell performance due to the evanescent character of generated near-fields around the NPs. With the optimized ~30–40 nm SiO 2 spacer layer, we observed an enhancement of solar cell efficiency from ~8.7 to ~10 %, which is due to the photocurrent enhancement in the off-resonance surface plasmon region. We also estimated minority carrier diffusion lengths ( L eff) from internal quantum efficiency data, which are also sensitive to SiO 2 spacer layer thickness. We observed that the L eff values are enhanced from ~356 to ~420 μm after placing Ag NPs on ~40 nm spacer layer due to improved forward (angular) scattering of light from the Ag NPs into silicon. 相似文献
3.
Localized surface plasmon resonance incurred by silver nanoparticles is used to enhance the photoelectric conversion efficiency of a TiO 2 nanorod-based dye-sensitized solar cell (DSSC). Improved light transmission is observed experimentally in silver nanoparticle-coated FTO glass. The transmission data are used to explore the effect on electrical parameters of DSSC using theoretical model. Current density increased from 11.7 to 12.34 mA/cm 2 and open-circuit voltage increased from 704 to 709.5 mV. Overall efficiency enhancement of 6.67 % is observed in TiO 2 nanorod-based DSSC due to plasmon-induced light trapping. 相似文献
4.
Fullerene-based bi-functional nanocomposite thin film (Ag nanoparticles embedded in fullerene C 70 matrix) is synthesized by thermal co-deposition method. Thermal stability of Ag-C 70 nanocomposite is investigated by annealing the nanocomposite thin film at different temperatures from 80 to 350 °C for 30 min. Optical and structural properties of nanocomposite thin film with respect to high temperature are studied by UV-visible spectroscopy and x-ray diffraction, respectively. Transmission electron microscopy is performed to observe the temperature-dependent size evolution of Ag nanoparticles in fullerene C 70 matrix. A large growth of Ag nanoparticles is observed with temperature especially above 200 °C due to enhanced diffusion of Ag in fullerene C 70 at higher temperature and Ostwald ripening. The properties of metal-fullerene nanocomposite is not significantly affected up to a temperature of 150 °C. With a further increase in temperature, a major blue shift of ~?33 nm in SPR wavelength is seen at a temperature of 300 °C due to the thermal induced structural transformation of fullerene C 70 matrix into amorphous carbon. A very large-sized Ag nanoparticle with a wide size distribution varying from 27.8 ± 0.6 to 330.0 ± 4.5 nm is seen at 350 °C and due to which, a red shift of ~?16 nm is obtained at this temperature. This study throws light on the thermal stability of the devices based on metal-fullerene bi-functional nanocomposite. 相似文献
5.
Surface plasmonic-enhanced light trapping from metal nanoparticles is a promising way of increasing the light absorption in the active silicon layer and, therefore, the photocurrent of the silicon solar cells. In this paper, we applied silver nanoparticles on the rear side of polycrystalline silicon thin film solar cell and systematically studied the dielectric environment effect on the absorption and short-circuit current density (Jsc) of the device. Three different dielectric layers, magnesium fluoride (MgF 2, n?=?1.4), tantalum pentoxide (Ta 2O 5, n?=?2.2), and titanium dioxide (TiO 2, n?=?2.6), were investigated. Experimentally, we found that higher refractive index dielectric coatings results in a redshift of the main plasmonic extinction peak and higher modes were excited within the spectral region that is of interest in our thin film solar cell application. The optical characterization shows that nanoparticles coated with highest refractive index dielectric TiO 2 provides highest absorption enhancement 75.6 %; however, from the external quantum efficiency characterization, highest short-circuit current density Jsc enhancement of 45.8 % was achieved by coating the nanoparticles with lower refractive index MgF 2. We also further optimize the thickness of MgF 2 and a final 50.2 % Jsc enhancement was achieved with a 210-nm MgF 2 coating and a back reflector. 相似文献
6.
In this work, the structural, compositional, optical, and dielectric properties of Ga 2S 3 thin films are investigated by means of X-ray diffraction, scanning electron microscopy, energy dispersion X-ray analysis, and ultraviolet—visible light spectrophotometry. The Ga 2S 3 thin films which exhibited amorphous nature in its as grown form are observed to be generally composed of 40.7 % Ga and 59.3 % S atomic content. The direct allowed transitions optical energy bandgap is found to be 2.96 eV. On the other hand, the modeling of the dielectric spectra in the frequency range of 270–1,000 THz, using the modified Drude-Lorentz model for electron-plasmon interactions revealed the electrons scattering time as 1.8 ( fs), the electron bounded plasma frequency as ~0.76–0.94 ( GHz) and the reduced resonant frequency as 2.20–4.60 ×10 15 ( Hz) in the range of 270–753 THz. The corresponding drift mobility of electrons to the terahertz oscillating incident electric field is found to be 7.91 ( cm 2/ Vs). The values are promising as they nominate the Ga 2S 3 thin films as effective candidates in thin-film transistor and gas sensing technologies. 相似文献
7.
As a wide‐bandgap semiconductor, titanium dioxide (TiO 2) with a porous structure has proven useful in dye‐sensitized solar cells, but its application in low‐cost, high‐efficiency inorganic photovoltaic devices based on materials such as Cu(InGa)Se 2 or Cu 2ZnSnS 4 is limited. Here, a thin film made from solution‐processed TiO 2 nanocrystals is demonstrated as an alternative to intrinsic zinc oxide (i‐ZnO) as the window layer of CuInS xSe 1?x solar cells. The as‐synthesized, well‐dispersed, 6 nm TiO 2 nanocrystals are assembled into thin films with controllable thicknesses of 40, 80, and 160 nm. The TiO 2 nanocrystal films with thicknesses of 40 and 80 nm exhibit conversion efficiencies (6.2% and 6.33%, respectively) that are comparable to that of a layer of the typical sputtered i‐ZnO (6.42%). The conversion efficiency of the devices with a TiO 2 thickness of 160 nm decreases to 2.2%, owing to the large series resistance. A 9‐hour reaction time leads to aggregated nanoparticles with a much‐lower efficiency (2%) than that of the well‐dispersed TiO 2 nanoparticles prepared using a 15‐hour reaction time. Under optimized conditions, the champion TiO 2 nanocrystal‐film‐based device shows even higher efficiency (9.2%) than a control device employing a typical i‐ZnO film (8.6%). 相似文献
8.
A efficient indium tin oxide (ITO)‐free transparent electrode based on an improved Ag film is designed by introducing small amount of Al during co‐deposition, producing ultrathin and smooth Ag film with low loss. A transparent electrode as thin as 4 nm is achieved by depositing the film on top of Ta 2O 5 layer, and organic solar cells based on such ultrathin electrode are built, producing power conversion efficiency over 7%. The device efficiency can be optimized by simply tuning Ta 2O 5 layer thickness external to the organic photovoltaic (OPV) structure to create an optical cavity resonance inside the photoactive layer. Therefore Ta 2O 5/Al‐doped Ag films function as a high‐performance electrode with high transparency, low resistance, improved photon management capability and mechanical flexibility. 相似文献
9.
An open‐circuit voltage ( Voc) of 1.57 V under simulated AM1.5 sunlight in planar MAPbBr 3 solar cells with carbon (graphite) electrodes is obtained. The hole‐transport‐material‐free MAPbBr 3 solar cells with the normal architecture (FTO/TiO 2/MAPbBr 3/carbon) show little hysteresis during current–voltage sweep under simulated AM1.5 sunlight. A solar‐to‐electricity power conversion efficiency of 8.70% is achieved with the champion device. Accordingly, it is proposed that the carbon electrodes are effective to extract photogenerated holes in MAPbBr 3 solar cells, and the industry‐applicable carbon electrodes will not limit the performance of bromide‐based perovskite solar cells. Based on the analysis of the band alignment, it is found that the voltage (energy) loss across the interface between MAPbBr 3 and carbon is very small compared to the offset between the valence band maximum of MAPbBr 3 and the work function of graphite. This finding implies either Fermi level pinning or highly doped region inside MAPbBr 3 layer exists. The band‐edge electroluminescence spectra of MAPbBr 3 from the solar cells further support no back‐transfer pathways of electrons across the MAPbBr 3/TiO 2 interface. 相似文献
10.
In this work, the effect of circular nanocavity on light trapping in a c-Si solar cell was studied by finite difference time domain (FDTD) simulation. The structure of the solar cell was considered to be Si 3N 4/c-Si/Ag, where the Ag layer was pattered and conformal growth of Si and Si 3N 4 was considered. The absorption spectra in the thin Si layer were determined and found 40 times higher at the infrared region (beyond 800 nm). For qualitative analysis, the short-circuit current of the solar cell was determined computationally by AM 1.5G solar illumination and found to be 2.1 times higher in the case of nanocavity as that compared to un-patterned solar cell. The enhancement in absorption in the solar cell is attributed to the different plasmonic modes coupled in the thin c-Si layer. The incident angle-dependent study was performed to observe the effect on enhancement in wide-angle incidence. The thickness-dependent study confirms 2.1 to 1.75 times enhancement in short-circuit current in 100- to 250-nm-thick c-Si layer. Therefore, this observation suggests that this structure has good prospect in achieving high conversion efficiency while reducing the device cost. 相似文献
11.
The recent surge in efficiency and progress of organohalide perovskite solar cells (PSCs) has been significant. The PSC performance is significantly influenced by nanostructuring as this varies the intrinsic optical, electrical, and electrochemical properties. Diverse TiO 2 electron transport layers (ETLs) are solvothermally grown on the transparent conducting oxide substrate with different dimensionalities, 0D nanoparticles (TNP), 1D nanowires (TNW) to 2D nanosheets (TNS), by varying the organic solvent used. These layers feature enhanced optical transparency (≈2%–5% transmittance improvement compared to pristine fluorine doped tin oxide, FTO, glass) minimizing light absorption losses. PSCs constructed using 1D TNW or 2D TNS yield enhanced photovoltaic performance compared to the 0D TNP counterparts. This is a result of i) improved infiltration of the perovskite in the porous TNW or TNS network and ii) facilitated electron transport and charge extraction at the TNW/perovskite or TNS/perovskite interfaces, thus reduced interfacial recombination loss. Employing a bilayered ETL film consisting of a self‐assembled TiO 2 blocking layer and a subsequent TNW active layer, produces PSC devices with an efficiency exceeding 16%. This bilayered ETL film can simultaneously block the photogenerated holes and enhance electron extraction, therefore improving PSC performance. 相似文献
12.
Novel thin film composite photocathodes based on device‐grade Cu(In,Ga)Se 2 chalcopyrite thin film absorbers and transparent conductive oxide Pt‐implemented TiO 2 layers on top are presented for an efficient and stable solar‐driven hydrogen evolution. Thin films of phase‐pure anatase TiO 2 are implemented with varying Pt‐concentrations in order to optimize simultaneously i) conductivity of the films, ii) electrocatalytic activity, and iii) light‐guidance toward the chalcopyrite. Thereby, high incident‐photon‐to‐current‐efficiencies of more than 80% can be achieved over the full visible light range. In acidic electrolyte (pH 0.3), the most efficient Pt‐implemented TiO 2–Cu(In,Ga)Se 2 composite electrodes reveal i) photocurrent densities up to 38 mA cm ?2 in the saturation region (?0.4 V RHE, reversible hydrogen electrode), ii) 15 mA cm ?2 at the thermodynamic potential for H 2‐evolution (0 V RHE), and iii) an anodic onset potential shift for the hydrogen evolution (+0.23 V RHE). It is shown that the gradual increase of the Pt‐concentration within the TiO 2 layers passes through an efficiency‐ and stability‐maximum of the device (5 vol% of Pt precursor solution). At this maximum, optimized light‐incoupling into the device‐grade chalcopyrite light‐absorber as well as electron conductance properties within the surface layer are achieved while no degradation are observed over more than 24 h of operation. 相似文献
13.
TiO 2 nanotube arrays (TiO 2 NTs) were fabricated by anodic oxidation and then Ag nanoparticles (Ag NPs) were assembled in TiO 2 NTs (Ag/TiO 2 NTs) by microwave-assisted chemical reduction. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence spectrum (PL), UV–vis absorption spectrum (UV–vis), and Raman spectrum, respectively. The results showed that Ag NPs were well dispersed on the surface of TiO 2 NTs with metallic state. The surface plasmon resonance (SPR) effect of Ag NPs could extend the visible light response and enhance the absorption capacity of TiO 2. Furthermore, Ag NPs could also restrain the recombination of photo-generated electron–hole pairs of TiO 2 NTs efficiently. The methylene blue photodegradation experiment proved that the SPR phenomenon had an effect on photoreaction enhancement. The results of photocatalytic water splitting indicated that Ag/TiO 2 NTs samples had better photocatalytic performance than pure TiO 2 NTs. The corresponding hydrogen evolution rate of Ag/TiO 2 NTs prepared with 0.002 M AgNO 3 solution was 3.3 times as that of pure TiO 2 NTs in the test condition. Additionally, the mechanism of catalyst activity enhanced by SPR effect was proposed. 相似文献
14.
Earth‐abundant Cu 2BaSnS 4 (CBTS) thin films exhibit a wide bandgap of 2.04–2.07 eV, a high absorption coefficient > 10 4 cm ?1, and a p‐type conductivity, suitable as a top‐cell absorber in tandem solar cell devices. In this work, sputtered oxygenated CdS (CdS:O) buffer layers are demonstrated to create a good p–n diode with CBTS and enable high open‐circuit voltages of 0.9–1.1 V by minimizing interface recombination. The best power conversion efficiency of 2.03% is reached under AM 1.5G illumination based on the configuration of fluorine‐doped SnO 2 (back contact)/CBTS/CdS:O/CdS/ZnO/aluminum‐doped ZnO (front contact). 相似文献
15.
Group III–V compound semiconductors are a promising group of materials for photoelectrochemical (PEC) applications. In this work, a metal assisted wet etching approach is adapted to acquiring a large‐area patterned microdome structure on p‐GaAs surface. In addition, atomic layer deposition is used to deposit a TiO 2 protection layer with controlled thickness and crystallinity. Based on a PEC photocathode design, the optimal configuration achieves a photocurrent of ?5 mA cm ?2 under ?0.8 V versus Ag/AgCl in a neutral pH electrolyte. The TiO 2 coating with a particular degree of crystallization deposited via controlled temperature demonstrates a superior stability over amorphous coating, enabling a remarkably stable operation, for as long as 60 h. The enhanced charge separation induced by favorable band alignment between GaAs and TiO 2 contributes simultaneously to the elevated solar conversion efficiency. This approach provides a promising solution to further development of group III–V compounds and other photoelectrodes with high efficiency and excellent durability for solar fuel generation. 相似文献
16.
The design and performance of solar cells based on InP grown by the nonepitaxial thin‐film vapor–liquid–solid (TF‐VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p‐InP absorber layer, n‐TiO 2 electron selective contact, and indium tin oxide transparent top electrode. An ex situ p‐doping process for TF‐VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open‐circuit voltage ( VOC) of 692 mV, short‐circuit current ( JSC) of 26.9 mA cm ?2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured VOC under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p‐InP. 相似文献
17.
Overcoming ionic diffusion limitations is essential for the development of high‐efficiency dye‐sensitized solar cells based on cobalt redox mediators. Here, improved mass transport is reported for photoanodes composed of mesoporous TiO 2 beads of varying pore sizes and porosities in combination with the high extinction YD2‐ o‐C8 porphyrin dye. Compared to a photoanode made of 20 nm‐sized TiO 2 particles, electrolyte diffusion through these films is greatly improved due to the large interstitial pores between the TiO 2 beads, resulting in up to 70% increase in diffusion‐limited current. Simultaneously, transient photocurrent measurements reveal no mass transport limitations for films of up to 10 μm thickness. In contrast, standard photoanodes made of 20 nm‐sized TiO 2 particles show non‐linear behavior in photocurrent under 1 sun illumination for a film thickness as low as 7 μm. By including a transparent thin mesoporous TiO 2 underlayer in order to reduce optical losses at the fluorine‐doped tin oxide (FTO)‐TiO 2 interface, an efficiency of 11.4% under AM1.5G 1 sun illumination is achieved. The combination of high surface area, strong scattering behavior, and high porosity makes these mesoporous TiO 2 beads particularly suitable for dye‐sensitized solar cells using bulky redox couples and/or viscous electrolytes. 相似文献
18.
The role of Au@SiO 2 core-shell nanoparticles on optical properties of perovskite solar cells has been explored using both the theoretical computations and the experiments. A quasi-static model is used to study the surface plasmon resonances (SPRs) of Au@SiO 2 core-shell nanospheres. Au@SiO 2 core-shell nanoparticles, with varying shell thickness and core radius, were assumed to be embedded in methylammonium lead triiodide (CH 3NH 3PbI 3) perovskite active layer. Enhanced absorption in the active layer is obtained due to the near-field plasmonic effect of the embedded core-shell nanoparticles. Theoretical modelling shows that a shell thickness of 1 nm and core diameter of 20 nm provide absorption enhancement in the orange-red region of the electromagnetic spectrum. Experiments performed using ~20-nm-sized Au@SiO 2 core-shell nanoparticles (with a shell thickness of ~1 nm) clearly demonstrate the enhanced absorption and the resulting enhancement in photocurrent due to the plasmonic effects. An efficiency enhancement of over 18 % is obtained for the best plasmonic perovskite solar cell containing Au@SiO 2 nanoparticles in Au@SiO 2-TiO 2 weight ratio of ~1 %. Incident photon-to-current conversion efficiency (IPCE) data also showed enhancement in photocurrent for the plasmonic device. The quasi-static modelling approach provides a good correlation between theory and experiment. 相似文献
19.
Nanopatterned CuInGaS 2 (CIGS) thin films synthesized by a sol‐gel‐based solution method and a nanoimprint lithography technique to achieve simultaneous photonic and electrical enhancements in thin film solar cell applications are demonstrated. The interdigitated CIGS nanopatterns in adjacent CdS layer form an ordered nanoscale heterojunction of optical contrast to create a light trapping architecture. This architecture concomitantly leads to increased junction area between the p‐CIGS/n‐CdS interface, and thereby influences effective charge transport. The electron beam induced current and capacitance–voltage characterization further supports the large carrier collection area and small depletion region of the nanopatterned CIGS solar cell devices. This strategic geometry affords localization of incident light inside and between the nanopatterns, where created excitons are easily dissociated, and it leads to the enhanced current generation of absorbed light. Ultimately, this approach improves the efficiency of the nanopatterned CIGS solar cell by 55% compared to its planar counterpart, and offers the possibility of simultaneous management for absorption and charge transport through a nanopatterning process. 相似文献
20.
In this paper, a novel method of preparation and systematic study of application of low-loss tin oxide (SnO 2) nanospheres located at the rear side of crystalline silicon solar cells having partial rear contact have been presented. The improvement in efficiency due to light harvesting through optical scattering of tin oxide nanospheres is significant for thin silicon solar cells. Finite-difference time-domain (FDTD) simulations reveal that embedding of the rear-located nanospheres is necessary for back scattering of light from the rear surface. An analytical electrical model has been developed utilizing the results of optical simulations to estimate the solar cell parameters and efficiency enhancement of solar cells. The model shows that an absolute efficiency enhancement of ~19% can be achieved for 16% efficient 10-μm thin silicon solar cell with partial rear contact. The enhancement is lower (~6%) for thicker (180 μm) partial rear contact cells. Experimentally, SnO 2 nanospheres have been synthesized and applied at the rear side of partial rear contact solar cell as a proof of experiment to validate the potential of this approach. A relative enhancement of short-circuit current by 2.3% and open-circuit voltage by 2.5% has been achieved experimentally for 180-μm silicon solar cells leading to 5.2% higher efficiency with respect to baseline efficiency validating this concept. 相似文献
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