Si/PEDOT:Interfacial Modification Of PSS Hybrid Solar Cells And Their Efficiency Enhancement

Compared with the traditional crystalline silicon solar cells,a novel organic-inorganic hybrid heterojunction solar cell has received great attention owing to their simple preparation technology and low cost in recent years.Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)has been widely used in the field of silicon-based heterojunction solar cells due to its good light permeability and high conductivity.However,the current preparations of organic-inorganic hybrid heterojunction solar are still complicated and expensive.Thus,improve the performance of Si/PEDOT:PSS hybrid solar cell with a simpler and lower-cost manufacturing process has become a research hotspot.This paper mainly aims at improving the performance of Si/PEDOT: PSS hybrid solar cells.The effects of PEDOT:PSS film thickness and different silicon substrate suede structure on performance of Si/PEDOT:PSS devices are systematically studied by regulating the PEDOT:PSS film thickness and silicon wafer thickness for the sake of preparpng Si/PEDOT: PSS hybrid solar cells with high performance and low cost.The main contents and conclusions are as follows:The effects of spin coating rate and silicon wafer thickness on performance of Si/PEDOT:PSS devices are analyzed in detail.The results showed that when the spin-coating rate is 1000 rpm,the moderate PEDOT: PSS film thickness,the best cell photoelectric conversion efficiency is obtained to be 2.98%,attributing to the fully absorbed incident light energy and appropriate resistance.Based on the above situation,50 wt.% KOH solution is used to reduce the thickness of 500?m n-type single crystal silicon wafers to varying degrees.The results show that the reduction rate is 22.1 nm/s under the reaction temperature of 75?.When the thickness of the silicon wafer is 338 ?m,the prepared solar cell reach up the best photoelectric conversion efficiency to be 5.17%.The effects of silicon nanowires(Si NWs),silicon pyramids(Si Pa)and silicon inverted pyramids(Si IPa)on the performance of Si/PEDOT:PSS hybrid solar cells are systematically studied.The results reveal that compared with the alkaline texturing system(KOH-IPA),the metal-assisted chemical etching(MACE)suede exhibited excellent light reduction ability.Si NWs express the optimum light trapping effect and the light absorption rate reached 90%,but for the reason that its high-density trap states to promote the carrier-recombination process at the organic-inorganic interface,the solar cell performance is the worst.As for the positive pyramid structure,the photoelectric conversion efficiency of the solar cell is further improved to 5.49%.It may be because that the positive pyramid structure can effectively reduce the surface area after using the KOH solution to be smooth due to the advantages of its large size structure,and themicro-nano structure distribution is more uniform,which is beneficial to suppress the recombination process of carriers and form a good junction contact.Finally,a large-angle inverted pyramid structure is constructed so that the valley bottom and valley peak of the inverted pyramid exceeded 126°.This structure ensures that the PEDOT:PSS mixed solution can more easily penetrate into the micro-nano structure silicon substrate,for the sake of sufficient light absorption and lower surface recombination speed.At the same time,taking advantage of the easy access and easy exit of the large channel during the spin coating process,inverted pyramid structure can effectively reduce the accumulation of valley bottom solution and form a large area of high-quality junction contact.Thus,the photoelectric conversion efficiency is further improved to 6.04%.Through the above research,the results show that the organic-inorganic hybrid heterojunction solar cell has broad application potential for the high efficiency and low cost solar cells in the future.