The use of an ITO‐free MoO3/Ag/MoO3 anode to control the photon harvesting in PCDTBT:PC70BM solar cells is proposed. At first sight, the fact that these anodes possess reduced far‐field transmission ...compared to ITO may seem to be a disadvantage. But, despite this, we show that by carefully tuning the resonant optical cavity we can enhance the external quantum efficiency close to the band edge of PCDTBT, resulting in high photocurrent and power conversion efficiency on par with ITO.
In this work, ray tracing is used to investigate the effects of pyramid texture angle towards light absorption and photocurrent in 250 μm-thick crystalline silicon (c-Si) absorber. Upright pyramids ...with texture angles of 10-50o are investigated. Planar c-Si absorber is used as a reference. When the pyramid angle increases, the broadband reflection reduces due to enhanced light scattering which leads to improved light absorption. At angle of 50o, the weighted average reflection (WAR) reduces to 14.7% and broadband light absorption increases. The optical path length enhancement increases to 12 at wavelength of 1100 nm. The reflection and photogenerated current density (Jg) exhibit an inverse relationship with increasing zenith angle. With increasing zenith angle, the reflection from the c-Si absorber increases and this results in lower light absorption and Jg. In the passivated emitter rear cell (PERC) solar cell, the planar solar cell exhibits short-circuit current density (Jsc) of 26 mA/cm2 with conversion efficiency of 13.6%. When both the pyramids and the silicon nitride (SiNx) anti-reflective coating (ARC) are incorporated on the solar cell, the Jsc increases to 39 mA/cm2 and conversion efficiency increases to 20.5%. This is attributed to the enhanced light-trapping and light-coupling effects in the device.
This paper deals with one competent light trapping structure of metamaterials embedded p-Si/n-ZnO-based thin solar cell assisted by different simulation studies. Through this article, the author ...exposed the credibility of ZnO as multidimensional material with dual utility to serve as anti-reflective coating with active material of this heterojunction solar cell. Additionally, dielectric metamaterial like silica nanoparticles on top of the structure enhanced the photon cultivation efficiency of the device. Further through this work, the author tries to validate the simulated structure in real world by the process of simple fabrication technique, which also offers same optical responses already given by theoretical studies. This investigation also confirms the metamaterial property of the monolayer silica nanoparticles in higher angle of incidence of light, which validates its utility in solar cell where injection of photon is needed throughout the day..
Effective photon management is critical to realize high power conversion efficiencies for thin crystalline silicon (c‐Si) solar cells. Standard few‐100‐µm‐thick bulk cells achieve light trapping with ...macroscopic surface textures covered by thin, continuous antireflection coatings. Such sizeable textures are challenging to implement on ultrathin cells. Here, it is illustrated how nanoscale Mie‐resonator‐arrays with a bimodal size distribution support multiple resonances that can work in concert to achieve simultaneous antireflection and light‐trapping across the broad solar spectrum. The effectiveness of these light‐trapping antireflection coatings is experimentally demonstrated on a 2.8 µm‐thick c‐Si solar cell. The measured short‐circuit current and corresponding power conversion efficiency are notably improved, achieving efficiencies as high as 11.2%. Measurements of the saturation current density on completed cells indicate that thermal oxides can effectively limit surface recombination. The presented design principles are applicable to a wide range of solar cells.
A nanophotonic design strategy to realize Mie‐resonator arrays that can combine antireflection and light‐trapping functions in a single, thin layer is discussed. The proposed light‐trapping antireflection coating is experimentally demonstrated on a 2.8 µm‐thick crystalline silicon (c‐Si) solar cell, resulting in a 48% enhancement in the short‐circuit current as compared to a planar cell and an absolute efficiency of 11.2%.
We experimentally demonstrate photocurrent enhancement in ultrathin Cu(In,Ga)Se2 (CIGSe) solar cells with absorber layers of 460 nm by nanoscale dielectric light scattering patterns printed by ...substrate conformal imprint lithography. We show that patterning the front side of the device with TiO2 nanoparticle arrays results in a small photocurrent enhancement in almost the entire 400–1200 nm spectral range due to enhanced light coupling into the cell. Three-dimensional finite-difference time-domain simulations are in good agreement with external quantum efficiency measurements. Patterning the Mo/CIGSe back interface using SiO2 nanoparticles leads to strongly enhanced light trapping, increasing the efficiency from 11.1% for a flat to 12.3% for a patterned cell. Simulations show that optimizing the array geometry could further improve light trapping. Including nanoparticles at the Mo/CIGSe interface leads to substantially reduced parasitic absorption in the Mo back contact. Parasitic absorption in the back contact can be further reduced by fabricating CIGSe cells on top of a SiO2-patterned In2O3:Sn (ITO) back contact. Simulations show that these semitransparent cells have similar spectrally averaged reflection and absorption in the CIGSe active layer as a Mo-based patterned cell, demonstrating that the absorption losses in the Mo can be partially turned into transmission through the semitransparent geometry.
Solar desalination driven by solar radiation as heat source is freely available, however, hindered by low efficiency. Herein, we first design and synthesize black titania with a unique nanocage ...structure simultaneously with light trapping effect to enhance light harvesting, well-crystallized interconnected nanograins to accelerate the heat transfer from titania to water and with opening mesopores (4–10 nm) to facilitate the permeation of water vapor. Furthermore, the coated self-floating black titania nanocages film localizes the temperature increase at the water–air interface rather than uniformly heating the bulk of the water, which ultimately results in a solar–thermal conversion efficiency as high as 70.9% under a simulated solar light with an intensity of 1 kW m–2 (1 sun). This finding should inspire new black materials with rationally designed structure for superior solar desalination performance.
To improve the receiver's solar-thermal conversion efficiency at high temperature for the next-generation concentrating solar power (CSP), a receiver with the light-trapping nanostructured coating is ...proposed herein. However, for the CSP plant with the light-trapping nanostructure coated receiver, the scale of the heliostat field is on the order of meters (∼10m), the solar receiver tube on the order of millimeters (∼10 mm), and the light-trapping coating on the order of nanometers (∼100 nm). The whole system spans nine orders of magnitude, which makes it extremely complicated and difficult to evaluate the receiver's optical and thermal performance. To solve this problem, a multi-scale model is proposed by combining Monte Carol Ray tracing method (MCRT), finite difference time domain (FDTD) method, and finite volume method (FVM). Then, the influences of three typical light-trapping nanostructured coatings, including pyramid nanostructure, moth-eye nanostructure, and cone nanostructure, on the receiver's optical-thermal performance are studied. Among these three typical nanostructures, the cone nanostructure can maximize the receiver's optical-thermal performance, with a receiver efficiency more than 88%, which is higher than that of the commercial Pyromark2500 coating by 6–10% points. The study demonstrates that the receiver with light-trapping nanostructured coatings can achieve high receiver efficiency for the next-generation CSP.
Solar energy is abundant and environmentally friendly. Light trapping in solar-energy-harvesting devices or structures is of critical importance. This article reviews light trapping with metallic ...nanostructures for thin film solar cells and selective solar absorbers. The metallic nanostructures can either be used in reducing material thickness and device cost or in improving light absorbance and thereby improving conversion efficiency. The metallic nanostructures can contribute to light trapping by scattering and increasing the path length of light, by generating strong electromagnetic field in the active layer, or by multiple reflections/absorptions. We have also discussed the adverse effect of metallic nanostructures and how to solve these problems and take full advantage of the light-trapping effect.
The Front Cover shows the development of Roll‐to‐Roll (R2R) light‐management foils integrated into fully scalable non‐fullerene acceptor (NFA)‐based organic photovoltaics (OPV) to enhance light ...absorption in, and power conversion efficiency of, the solar cells. The R2R light‐management foils are demonstrated to provide a 25% enhancement in power conversion efficiency enhancement for the NFA OPV, demonstrating that this may be a viable route for boosting the performance of industrial OPV in the future. More information can be found in the Full Paper by M. A. Yakoob et al.
By reducing the thickness of the absorber layers, ultrathin GaAs solar cells can be fabricated in a more cost‐effective manner using less source material and shorter deposition times. In this work, ...ultrathin GaAs solar cells are presented with a diffuse scattering layer based on wide bandgap GaP grown directly on the device layers of the cells with MOCVD. The roughness and surface morphology are quantified using atomic force microscopy and the resulting diffuse scattering capability is assessed using wavelength‐dependent reflectance measurements. Ohmic rear contacts are made using contact points etched through the GaP layer, for which an etching procedure using I2:KI was developed and optimized. The performance of the GaP textured ultrathin GaAs cells are compared with equivalent planar cells using current density‐voltage measurements and external quantum efficiency measurements, where the GaP textured cells demonstrate an increase of 6.7% in the short‐circuit current density (JSC), which was found to be as high as 21.9 mA·cm−2 as a result of increased photon absorption by light‐trapping.
Ultrathin GaAs solar cells are presented with a diffuse scattering layer based on wide bandgap GaP grown directly on the device layers of the cells with MOCVD. The performance of the cells is compared to equivalent planar cells using current density‐voltage measurements and external quantum efficiency measurements, where the GaP textured cells demonstrate an increase of 6.7% in the short‐circuit current density as a result of increased photon absorption by light‐trapping.
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