The Design And Optimization Of Thin Film Solar Cells With Periodic Light Trapping Structure

With the large-scale exploitation and utilization of fossil energy,the issue of carbon emissions has gradually attracted people’s attention.The fundamental measure to achieve the goal of carbon emission reduction is to change the main energy source and accelerate the replacement of traditional energy with clean energy and high-efficiency electric energy.Nowadays,solar energy has become one of the most dynamic research fields in renewable energy,and solar cells that can directly convert solar energy into electrical energy have attracted the favor of many researchers.However,in addition to high production costs,solar cells also have the disadvantage of low photoelectric conversion efficiency due to light loss.Therefore,this paper introduces suitable light trapping structures to achieve the effective utilization frequency band of solar spectrum and enhance the efficiency of light trapping.The finite difference time domain method（FDTD）has been used to optimize the size of the structure and explore the light trapping effect of different periodic light trapping structures applied to solar cells.At first,this paper builds four periodic nanostructured silicon nitride（Si₃N₄）antireflection layers:nanorod hole arrays,nanosquare hole arrays,inverted nanocone hole arrays,and inverted nanopyramid hole arrays applied to the front surface of the ultrathin crystal silicon solar cell to get the optimal nanostructures.Among them,the paper found that the nanoconical hole arrays have better optical properties than the nanocolumnar hole arrays.In the nanoconical hole structure,the light trapping performance of the nanocone hole is the best,with a gain of the short circuit current density of 29.46 m A/cm².Combining the optimal solar cell with a 120nm Ag back reflector,the photocurrent density of 32.20 m A/cm² is obtained,which is 41.35%higher than that of the control group（with 67 nm planar silicon nitride antireflection layer）and102.90%higher than that of the bare silicon with same thickness.Regarding the rule that the optical performance reflected by the nanoconical hole arrays is better than the nanocolumnar hole arrays,the paper further explores the light absorption of the nanocone structure on the ultra-thin crystalline silicon solar cells.It found that the nanoconical structure improved the light deficiency of nanocone hole structure within the wavelength of430-600 nm and obtained a stronger photocurrent density.The nanocone structure reaches a photocurrent destiny of 31.01 m A/cm²,which increases 1.55 m A/cm² compared with the inverted nanocone hole.The maximum short-circuit current density of the nanopyramid structure is 30.09 m A/cm²,which is 0.96 m A/cm² higher than that of the inverted nanopyramid hole structure.The short circuit current density of 32.95 m A/cm² is obtained by matching 100nm Ag back reflector with the optimal nano-cone structure solar cell.Finally,we designed the perovskite solar cells morphology with four kinds of nanostructures:nanohemisphere structure,nanorod structure,inverted nanocone structure and inverted nanopyramid structure,which were applied to the hole-transport layer of perovskite solar cells.The results show that the optimized nanohemisphere structure has the best light trapping effect,which obtain the short circuit current density of 23.82 m A/cm² and the absorption enhancement factor is 12.3%.