Simulation of Light Absorption Enhanced by Light Trapping Structure in Photoelectrochemical Cells
Objective With the growing consumption of non-renewable energy sources and the severe environmental pollution problems associated with them,society has become increasingly aware of the importance of clean energy.Researchers have continuously explored alternative energy sources,with solar and hydrogen energy at the forefront.Hydrogen,a clean energy source with high energy density,only produces water as a byproduct upon combustion,generating no greenhouse gases or other pollutants.Therefore,it is considered a vital component of the future energy structure.Hydrogen production through photoelectrochemical water splitting has attracted significant attention as a method to convert solar energy into hydrogen.Improving the efficiency of photoelectrochemical water splitting for hydrogen production remains a key challenge.Methods Using the finite-difference time-domain(FDTD)method,we simulate and compare the reflectivity of pyramid structures and inverted pyramid structures with varying aspect ratios.The goal is to determine which of these light trapping structures improves the performance of photoelectrochemical cells most effectively.In optimal cases,both structures had the same light absorption surface area.Therefore,we compare the absorption characteristics and performance of photoelectrochemical cells with pyramid and inverted pyramid structures,both having an aspect ratio of 0.6,using FDTD and Charge simulations.Results and Discussions Our findings show that increasing the depth(height)aspect ratio reduces the reflectivity of the photoanode,enhancing the light trapping effect for both structures.Through mathematical analysis and practical considerations regarding cost and manufacturing processes,we identify an optimal aspect ratio of 0.6 for both the pyramid and inverted pyramid structures.We compare the reflectivity and absorptivity of the two structures,as well as the short-circuit current density and maximum power of the cells.Results indicate that the absorptivity of the pyramid and inverted pyramid structures is increased by 40.16％and 45.44％,respectively,compared to flat plate structures.Maximum power is enhanced by 37％for the pyramid and 54％for the inverted pyramid structures,while the short-circuit current is enhanced by 17％and 34％,respectively.The fill factor(FF)of the photoelectrochemical cell improves from 0.69 to 0.78.Overall,the absorption of the inverted pyramid structure is 1.13 times higher than that of the pyramid structure,the short-circuit current density is doubled,and the maximum power is 1.46 times greater compared to the pyramid structure(Figs.5 and 6).Further electric field analysis reveals that the inverted pyramid structure exhibits superior light trapping capabilities compared to the pyramid structure.Conclusions In conclusion,the inverted pyramid structure outperforms the pyramid structure in terms of absorption rate,maximum power,and light capture ability.When selecting surface antireflective structures for photovoltaic devices,it is crucial to choose the most effective design.In recent years,surface antireflective structures have been increasingly adopted in solar and photoelectrochemical cells,leading to continuous efficiency improvements.These structures are expected to become more widely used in photovoltaic devices due to their ability to reduce reflectivity and enhance absorptivity.This study of the pyramid and inverted pyramid surface structures not only provides a basis for selecting antireflective shapes for optoelectronic devices but also offers insights into the application of micro/nano-processing and the light trapping mechanisms of various structures.
photoelectrochemical water splitting for hydrogen productionfinite-difference time-domainpyramid structureinverted pyramid structuremicro/nano machining
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