To address the discrepancy between carrier collection and light absorption of organic solar cells caused by the limited carrier mobility and optical absorption coefficient for the normally employed organic photoactive layers, a light management structure composed of a front indium tin oxide(ITO) nanograting and ultrathin Al layer inserted in between the photoactive layer and the electron transport layer(ETL) is introduced. Owing to the antireflection and light scattering induced by the ITO nanograting and the suppression of light absorption in the ETL by the inserted Al layer, the light absorption of the photoactive layer is significantly enhanced in a spectral range from 400 nm to 650 nm that also covers the main energy region of solar irradiation for the normally employed active materials such as the P3HT:PC_(61) BM blend. The simulation results indicate that comparing with the control device with a planar configuration of ITO/PEDOT:PSS/P3HT:PC_(61) BM(80-nm thick)/Zn O/Al, the short-circuit current density and power conversion efficiency of the optimized light management structure can be improved by 32.86% and 34.46%. Moreover, good omnidirectional light management is observed for the proposed device structure. Owing to the fact that the light management structure possesses the simple structure and excellent performance, the exploration of such a structure can be believed to be significant in fabricating the thin film-based optoelectronic devices. 相似文献
A highly dense and uniform layer of Au nanoparticles (NPs) on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film has been produced by the pulsed laser deposition (PLD) technique toward the production of an improved efficiency photovoltaic device. The advantage of PLD over other techniques is the easy and precise control of the Au NPs size and spatial distribution, without needing of further NP surface functionalization. The efficiency enhancement factor related to Au NPs doping has been evaluated in a solar cell based on poly-(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) diffused bilayer. The short-circuit current density, JSC, increases by 18 % and the power conversion efficiency by 22 %, respectively, in comparison with an equivalent device without Au NPs. The optical and morphological properties of the Au NPs layer have been selected in order to evaluate the contribution of the surface plasmon resonance as enhancement factor of the solar cell efficiency, in a range size where light scattering is negligible. 相似文献
The mobility enhancement of organic thin‐film transistors based on poly(3‐hexylthiophene) (P3HT) by incorporating gold nanorods (Au NRs) is reported. Through varying the doping concentration and surface modifier of the Au NRs in P3HT matrix, the P3HT/Au composite with 0.5 mg mL?1 pyridine‐capped Au NRs exhibits a hole mobility of 0.059 cm2 V?1 s?1, this value is seven times higher than that of pristine P3HT. This remarkable improvement of mobility originates from the enhanced crystallinity and optimized orientation of P3HT after doping with Au NRs. In addition, the appropriate surface modification can produce more‐efficient hole conduction of Au NRs. 相似文献
Four kinds of Au nanorods(NRs)with different aspect ratios are designed to adjust the relationship between resonance energy level of longitudinal(L)and transverse(T)modes.During the femto-second Z-scan experiments,huge saturable absorption phenomena are observed while the energy level T is located between one to two times of the energylevel L.This means that the energy may transfer between longitudinal and transverse energylevels in the same and/or different Au NRs.It effectively depresses the production of revised saturated absorption and increases the saturable absorption efficiency.This method is significant for the preparation of high-efficiency saturable absorption devices. 相似文献
We fabricated organic photovoltaic (OPV) devices containing various Au nanostructures mixed with hole-collecting buffer layer. The presence of the Au nanostructures results in enhancement of the external quantum efficiencies (EQE) at dissimilar wavelengths of visible light, which can be attributed to the modulated plasmonic absorption frequency of the Au nanostructures. In addition to this plasmonic effect induced by visible light absorption, an increase in the EQE was also found upon UV excitation, which can be attributed to scattering effects induced by Au particles. The optical response pattern of organic photovoltaic devices can be modulated in a wide range of visible and UV wavelengths, by controlling sizes and shapes of the Au nanostructures. 相似文献
Gold nanorods (NRs), rod-shaped gold nanoparticles, were modified with bovine serum albumin (BSA) and polyethylenimine (PEI)
using layer-by-layer technique. From absorption spectroscopy and zeta potential measurements, it was obvious that NRs were
wrapped with these polymers without aggregation of NRs. Following BSA modification, the surface-modified NRs (BSA-NRs) were
well-dispersed without aggregation in biochemical conditions, verified from absorption spectroscopy. Further modification
with PEI provided positively charged NRs (PEI-NRs). A transmission electron microscopy image of PEI-NRs revealed that the
surface modification did not affect changing the shape of the initial NRs. In addition, the PEI-NRs retained the colloidal
stability of BSA-NRs in biochemical conditions. We have evaluated that transfection activity of PEI-NRs with HeLa cells. From
results of gene expression experiments, it was obvious that the stabilization of NRs by BSA and further modification with
PEI realized transfection using NRs into cultured cells. Moreover, the cellular uptake of NRs enabled cellular imaging using
light scattering from the NRs. 相似文献
Gold (Au) nanomaterials are promising photothermal agents for the selective treatment of tumor cells owing to the strong capability to convert near‐infrared (NIR) irradiation into heat energy. One basic issue for practical photothermal therapy is the enhancement of photothermal effect in NIR region. Here, various low‐molecular‐weight thiols are applied to induce one‐dimensional (1D) self‐assembly of Au nanorods (NRs), which leads to the redshift of absorption peak towards NIR region. As a result, the 1D assembled Au NRs exhibit improved photothermal effect at 808 nm in comparison to unassembled Au NRs. 相似文献
Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-II) laser facilities with 350 nm wavelength, 0.6 ns pulse width and 20-80 Joules energies. Laser absorption, light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser absorption and scattered light were about 90% and 10%, respectively, under focusing irradiation, but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of focusing irradiation, the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity, X-ray conversion increased. This is highly advantageous to the inertial confinement fusion. However, X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irradiation was basically the same. 相似文献
For spherical Cu, Ag, and Au nanoparticles with a radius of 1–3 nm in copper phthalocyanine (CuPc), with allowance for internal
size effects, we calculate the scattering efficiency factor in the near zone, the extinction efficiency factor due to scattering
and absorption of incident radiation, and the efficiency of the increase in absorption by the matrix material. This occurs
in the CuPc absorption bands, as well as in the weak absorption region of CuPc, where, owing to surface plasmon resonance,
an additional absorption band arises for nanoparticles of all three materials. For Ag nanoparticles, the increase in absorption
is twice as high as for Cu and Au nanoparticles; for these it differs inconsiderably. 相似文献
We report to apply Al nanoparticles (NPs) to enhance the photovoltaic response of crystalline- or c-Si solar cell from the ultraviolet (UV) throughout the visible and near infrared (NIR) regimes. Al NPs were induced by solid thermal annealing and embedded in a SiO2 layer that was to passivate the front side of solar cell. Upon the excitation of surface plasmons (SPs) on the Al NPs under light illumination, an enhancement of broadband absorption of the solar cell was observed. The incorporation of Al NPs led to a relative 13.8% increase in photoelectric conversion efficiency of c-Si solar cell, and an external quantum efficiency enhancement from the UV throughout the visible and NIR regimes. The improvement of c-Si solar cell performance was attributed to both effects of absorption and scattering by SPs. 相似文献
Plasmonic metal nanoparticles have shown great promise in enhancing the light absorption of organic dyes and thus improving the performance of dye-sensitized solar cells (DSSCs). However, as the plasmon resonance of spherical nanoparticles is limited to a single wavelength maximum (e.g., ~ 520 nm for Au nanoparticles), we have here utilized silica-coated gold nanorods (Au@SiO2 NRs) to improve the performance at higher wavelengths as well. By adjusting the aspect ratio of the Au@SiO2 NRs, we can shift their absorption maxima to better match the absorption spectrum of the utilized dye (here we targeted the 600–800 nm range). The main challenge in utilizing anisotropic nanoparticles in DSSCs is their deformation during the heating step required to sinter the mesoporous TiO2 photoanode and we show that the Au@SiO2 NRs start to deform already at temperatures as low as 200 °C. In order to circumvent this problem, we incorporated the Au@SiO2 NRs in a TiO2 nanoparticle suspension that does not need high sintering temperatures to produce a functional photoanode. With various characterization methods, we observed that adding the plasmonic particles also affected the structure of the produced films. Nonetheless, utilizing this low-temperature processing protocol, we were able to minimize the structural deformation of the gold nanorods and preserve their characteristic plasmon peaks. This allowed us to see a clear redshift of the maximum in the incident photon-to-current efficiency spectra of the plasmonic devices (Δλ ~ 14 nm), which further proves the great potential of utilizing Au@SiO2 NRs in DSSCs.