The Application Of Surface Plasmon In Amousphous Silicon Solar Cells Light Trapping Structures

In the day of the shortage of traditional energy,solar cells that convert light energy into electrical energy by photovoltaic effect have become an important means of new energy utilization.Amorphous silicon thin film solar cells have the advantages of ultrathin structure,high absorption efficiency and mass production.However,how to maximize the absorption performance is still a problem to be solved.The design of the light trapping structure has become a common method in improving the absorption efficiency.Especially the surface plasmon effect of metal nanostructure has excellent performance in local energy enhancement and broadband absorption.At the same time,the thin film solar cells with multi-layer materials have gradually come to the eye of the people.The incidence rate of light can be increased by multi-layer of antireflective coating.Meanwhile,inserting multi-back reflection electrodes can prevent the scatter effect of back electrode materials and reduce the transmission loss of light.Therefore,the design of light trapping structure and multilayer structure have become two popular methods in obtaining high efficiency a-Si thin film solar cell.The main contents and innovation points of this paper are as follows:1)This paper introduces the theoretical model of flat solar cell.Different metal nanostructures on position,shape and size of the light trapping properties were analyzed.Through comparing performance parameters with reference flat structure,it can obtain the requirements of plasmonic trapping structure in designing a novel solar cell with high absorption efficiency.2)This paper also proposed the ultra-thin amorphous silicon thin film solar cell structure consisting of the front cosinusoid ITO grating and the ellipsoid metal back reflector.The front ITO gratings mainly use the scattering effect to improve the absorption efficiency at short wavelength.The metal back light trapping structure can use surface plasmon mode to improve the absorption efficiency at long wavelength.The absorption efficiency of the dual interface amorphous silicon solar cell can reach 75.36%under vertical light.It is 31.35%higher than that reference flat one,which the absorption efficiency is only 57.37%.In addition,the sensitivity of the new trapping structure to the angle of incident light is considered.The novel dual structure can maintain high absorption efficiency at the incident angle from 0° to 68°.3)Based on the structure parameters of the ordinary single layer solar cell,it has insert the additional antireflective layer and back electrode.It has become a new type of multilayer amorphous silicon cell.The absorption performance for different positions of light trapping structures have been studied.The absorption efficiency of multilayer flat solar cell can reach 75.36%.Meantime,with the design of back metal electrode trapping structure,the absorption efficiency can reach 80.29%.In summary,based on surface plasmonic light trapping structure,the ordinary layer and multilayer amorphous silicon thin film solar cells can achieve high absorption efficiency,broadband absorption and insensitive to the incident angle.It provides basis and guidance for the preparation of high efficiency thin film solar cells.