Investigation On The Enhancement Of Light Absorption In Perovskite Solar Cells Using Micro-structured Anti-reflection Films

Perovskite solar cells have developed rapidly since their inception,and the energy conversion efficiency(PCE)has reached 25.7%,which is close to the conversion efficiency of monocrystalline silicon solar cells.This is due to perovskite materials’ superior optoelectronic properties,which include longer carrier lifetimes,greater carrier mobility,and variable band gap width.It is vital to consider the lighting conditions of sunlight in different periods while using perovskite solar cells in outdoor locations.The incident angles of sunlight on the solar cell glass substrate vary throughout the day,and the Fresnel reflectivity of the interface between the solar cell glass substrate and the air increases as the incident angle increases,resulting in an decrease in solar cell efficiency as the incident angle increases.This is a key issue limiting the outdoor operation of solar cells.It is an effective solution to use a micronanostructured anti-reflection film on the surface of the perovskite solar cell substrate to enhance the cells’ absorption of oblique sunlight.However,there are many limitations in the preparation process of anti-reflection coatings,such as the use of electron beam lithography and plasma etching processes,which are time-consuming,expensive and complex;or the use of simple processes such as nanosphere lithography and self-assembly,but with poor uniformity or poor repeatability over large areas.We used holographic lithography and PDMS transcription to create a twodimensional grating structure anti-reflection film,and realized the omnidirectional light absorption enhancement of perovskite solar cells.This scheme allows for flexible adjustment of the grating structure’s period,as well as high throughput and repeatability.The anti-reflection film can effectively suppress the Fresnel reflection on the surface of the substrate when sunlight is incident obliquely,thereby increasing the number of photons inside the device.Through the light scattering of the two-dimensional grating structure,the effective optical path length of the incident light in the perovskite layer is increased.The efficiency of the perovskite solar cell with the anti-reflection film is20.27%,and the conversion efficiency is enhanced in all directions.The higher the incident light’s inclination angle,the larger the rise in PCE.In addition,the surface of the anti-reflection film has excellent hydrophobicity,which can improve the water resistance and self-cleaning performance of perovskite solar cells when working outdoors,which is beneficial to the stability of the device in outdoor work.