Office of Energy Efficiency & Renewable Energy NREL is operated by Midwest Research Institute Battelle Contract No. The surface roughness would impact on the overall performance. The dimensions of nanoparticles affect the absorption and efficiency of solar cells. Copyright © 2021 Elsevier B.V. or its licensors or contributors. First, a significant efficiency drop detected after adding the MNPs (related to the substantial number of defects left). Defects would spread around embedded MNPs causing loss that would increase even further with higher defect density. 5A). A 3D model of a thin film amorphous silicon solar cell has been developed which accounts for surface roughness as well. a solar cell based on amorphous silicon with a solar conversion efficiency of about 2.4% (for historical discussion see Reference [6, 7]). Working off-campus? … We use cookies to help provide and enhance our service and tailor content and ads. Doped layer thickness and doping level can impact the efficiency of thin film solar cell. They are designed for constructive interference. These enhancement methods are based on increasing the optical path length and embedding scatterers within cells. The hydrogenated amorphous silicon (a-Si:H) solar cell progress has been started from the invention of first Schottky device with an efficiency of 2.4% by Carlson and Wronski [ 1 ] and Kabir et al. However, light can face optical losses for small (few nanometer) MNPs that can supersede scattering. Our quantitative simulations confirm that the superabsorption bandwidth is maximized at the checkerboard pattern of the perforations. This success establishes the logistics to extrapolate models that include MNPs effects and the impact of their size, shape, and location of the device layers on solar cell efficiency. Effect of phosphorus doping on the performance of pin-type a-Si:H thin-film solar cells. Blue Light-Emitting Si Quantum Dots with Mesoporous and Amorphous Features: Origin of Photoluminescence and Potential Applications, Density Of State Conduction band, a‐Si –Ref, Difference between Defect level and intrinsic level N+,P+‐Ref, Difference between Defect level and intrinsic level intrinsic‐Ref, Refractive index of materials (attached to the top and the bottom of the absorber). For this reason the degree of freedoms to optimize the model are limited by the type and dimension of the original sample has already defined (in case of no MNPs). A new design methodology will be recommended in sections III and IV. [1] Oerelikon set the world record for stable amorphous solar cells to above 10% in 2009. The agreement seen in Figure 3B between simulation and measurement is good, and it validates our model again. Herein, some numerical simulations were performed to characterize and optimize different configuration of amorphous silicon-based thin-film solar cells. Hydrogenated amorphous silicon (a-Si:H) has been effectively utilized as photoactive and doped layers for quite a while in thin-film solar applications but its energy conversion efficiency is limited due to thinner absorbing layer and light degradation issue. Since during the fabrication process there is no control on the shape of silver NPs, then only two variables left for tuning thin film plasmon solar cells. Requires much less silicon. However, embedding MNPs can also cause significant structure defects and pronounced efficiency drop as well – it has been indicated by many experiments that disproved this belief. Alternatively, MNPs are intentionally placed within solar cells. (A) schematic of the P‐I‐N device; (B) EQE curve (dash line represents measurement, (A) Schematic of the P‐I‐N device; (B) EQE curve (dash line represents measurement, (A) Schematic of the P‐I‐N device; (B) Comparison of EQE with and without MNPs; solid line represents MNPs inside the P+ top layer of the a‐Si; dash line represents the case with No MNPs, (A) Schematic of the P‐I‐N device; (B) Using different size of MNPs, in two different locations EQE curve for the simulation (solid line represents after optimization‐black; dash line represents No MNPs blue). The efficiency of a-Si:H degrades over time under exposure to light. These MNPs can be made out of gold or silver, and both could exhibit great metal/plasmon behavior at optical frequencies and consequently would impact on amorphous silicon thin film solar cell's performance 11. In search of ways to improve efficiency, we have investigated the impact of MNP's size, and location within the solar cell, in addition to the effect of defects, and doping levels on the overall efficiency. Figure 7 shows the geometry of the whole structure in 3D with considering boundary conditions as well. Sanyo has developed a hybrid solar cell by applying coatings of amorphous silicon onto a mono-crystalline solar cell (see accompanying diagram). For instance, using TCO film with large grains would increase the surface roughness 24-26. Random textured or corrugated external/internal interfaces are used to improve scattering 2-8, while transparent conductive oxide (TCO) layers are utilized to minimize reflections at interfaces, additionally highly reflective surfaces are used to enhance back reflections. Finally simulation results indicate an impressive efficiency enhancement of up to ~30% which amounts to 13% overall efficiency. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username. Augmentation of power conversion efficiency of amorphous silicon solar cell employing poly(methyl methacrylate-co-acrylic acid) nanospheres encapsulated with gold nanoparticles. A. Damitha T. Adikaari, S. Ravi P. Silva, Michael J. Kearney and John M. Shannon Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford, GU2 7XH, United Kingdom. The flowchart in below shows how our 3D model of a solar cell works. Presence of defects can cause optical losses. The best power conversion efficiency to date is 2.4% in AM‐1 sunlight. Power losses, quantum efficiencies, and short-circuit currents of different layers of the cell are analyzed. In our model, silver nanoparticles are designed as spheres with 18 nm diameter and placed in a random 2D array with a maximum center‐to‐center spacing of 36 nm. The main reason that light trapping of MNPs for a‐Si solar cells (in the state of the art) only occurs in long wavelengths (above 500 nm) is that the observation of UV rays inside intrinsic layer or close to the device junction normally happens with very low intensity (regarding to the huge absorption occurs at the surface of the absorber). X. Deng . At this point, the intensity of light for the ultraviolet (UV) rays (high frequencies) close to the N‐type region (at the back) is very weak, since most of their energies have already been absorbed by the top layers of the absorber (i.e., inside the P+, and intrinsic region), and mostly Infrared (IR) rays exist. We also calculated the amount of efficiency, FF, Voc, and Jsc for various scenarios. This improvement is typically done using various light trapping techniques such as utilizing textured back reflectors for pronounced light scattering within the cell thus achieving higher absorption. Conventional solar photovoltaic thermal energy systems or PVTs can theoretically generate both electricity and heat. Figure 1 illustrates such enhancing techniques. If efficiencies of 10% can be reached on large area thin film amorphous silicon cells on inexpensive substrates, then this would be the best approach to … The boundary conditions, and the excitation in a 3D structure of the solar cell. Typically, any thin film solar cells suffer from a huge reduction in light absorption within absorber layers (semiconductors), and that can cause efficiency drop due to … It is certainly not recommended to embed large MNPs inside the active region, because it can cause a large amount of optical loss for the whole system. To understand the effect of existing silver nanoparticles, we studied solar cell's performance after embedding these MNPs at different layers, one layer at a time. Enhancing light absorption within thin film amorphous silicon (a-Si) solar cells should lead to higher efficiency. To improve the performance even further, the size, and location of MNPs should be optimized as well. Conclusion will be given in section V. Finally a methodology for a robust simulation will be presented in the Appendix. The highest efficiency, so far, detailed for single junction planar thin-film hydrogenated amorphous silicon solar cell is 10.2% , . The technologically most important thin amorphous film is probably represented by few nm thin SiO 2 layers serving as isolator above the conducting channel of a metal-oxide semiconductor field-effect transistor . Although in some cases like placing small MNPs close to the junction inside the semiconductor, it is not easy to get a quick convergence. Initialization of the input data is the crucial part of this work. We review the progresses and issues towards manufacturing hydrogenated amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) based thin film mul High efficiency amorphous and nanocrystalline silicon thin film solar cells on flexible substrates - IEEE Conference Publication The accuracy of the results is directly related to the input data. The amorphous silicon solar cells with the nanoporous PMMA AR coating realize an improvement in quantum efficiency (QE) up to 4% in 450-650nm spectral regions. So these issues associated with the design and fabrication, need to be resolved to enhance efficiency. It is suggested that small MNPs to be placed between the transparent electrode and the highly doped semiconductor at the top layer side, instead of inside the P+ region for ease of fabrication process. All through the exploration, the designed amorphous solar cell includes three original parts. Table 1 shows the list of parameters that are used for initialization of the 3D model. This cad tool used Finite Element Method (FEM) as a numerical method to solve the nonlinear system of PDEs. 17. Typically, the optical properties of MNPs are highly controlled by changing size 9, density 10, 15, conductivity 9, location 11, 16, and shape 12-14. They call this a … Three optical models are developed for comparative studies to optimize the performance of the solar cell. Mailing Address: 1520 Middle Drive Knoxville, TN 37996‐2250. Extinction coefficient of amorphous silicon. By continuing you agree to the use of cookies. Amorphous cells offer higher efficiency than the other two. A modeling toolbox was successfully developed for 3D solar cells performance analysis 17, and it was validated by previously published experimental data carried out by Ref. The optimized cell is seen – thus validating our models Elsevier B.V. or its licensors contributors! 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