Fabrication And Performance Of Flexible Perovskite Solar Cells Based On Electrospinning

In the textile field,smart textiles that can accommodate various small electronic devices have become the next generation of high-tech products.Therefore,powering these electronic devices has become a hot spot in the research field.One of the most effective methods is to use fibrous solar cells.And except for perovskite solar cells(PSCs),the remaining energy conversion efficiency(PCE)is much lower than that of silicon-based photovoltaic cells.Therefore,we choose the fibrous perovskite solar cell as the research direction.In this thesis,perovskite composite nanofibers are prepared by electrospinning as the photosensitive layer of solar cells.The flexible lead-based and tin-based perovskite solar cells were prepared to improve the photovoltaic performance of the cells.The influence of process parameters,active layer composition and cell structure on the photovoltaic performance of solar cells was systematically studied.The specific research content is as follows:(1)Research on the parameters and performance of electrospinning lead-based perovskite.Electrospinning technology is used to prepare perovskite-polyvinylpyrrolidone(PVP)nanofibers,so that perovskite crystals grow on the surface of PVP nanofibers to improve the optical properties and mechanical stability of the perovskite material.The process parameters of electrospinning were explored in detail,including spinning voltage,relative humidity,pushing speed and receiving distance,and the best spinning conditions were obtained.The investigation found that this method not only significantly increased the mechanical stability and cycle stability of the perovskite,but also gave the PVP nanofibers excellent optical properties,comparable to the two-dimensional structure.Proved that it has the development prospect of being applied to flexible perovskite solar cells.(2)Fabrication and performance study of flexible lead-based perovskite solar cells.The electrospinning process is used to coat CH₃NH₃Pb I₃-PVP nanofibers on the surface of silver yarn that has been dipped and loaded with poly(3-hexylthiophene)(P3HT).The photosensitive layer of the device is made of cathode yarn.Sn O₂-[6,6]-phenyl-C₆₁-butyric acid methyl ester(PCBM)was coated on carbon fiber(CF)to prepare anode yarn.Finally,a complete lead-based solar yarn is obtained by twisting or weaving.The structure of a single device is:Ag/P3HT/(CH₃NH₃Pb I₃-PVP)/(Sn O₂-PCBM)/CF.A double-twisted solar yarn can produce 15.7%PCE and has a long service life(>216 h).The solar fabric woven from lead-based solar yarn has an effective area of30.5 mm×30.5 mm,and its maximum energy density is 1.26 m W cm^-2.Proved to have good mechanical stability and photovoltaic characteristics,laying the foundation for the integration with smart textiles.(3)Fabrication and performance research of flexible tin-based perovskite solar cells.With CF as the cathode core yarn,P3HT was first loaded as a hole transport layer by dip coating.To further improve the PCE of the battery.The PCBM is incorporated into the perovskite precursor solution.Then the electrospinning method is used to load MASn I_3-xCl_x-C₆₁-PVP nanofibers on its surface.The optical nanofiber has the advantages of light absorption capacity>90%in the wavelength range of 300-550 nm,carrier lifetime of 300 ns(undoped PCBM is 278 ns),and good flexibility.Finally,it is twisted with silver yarn to make a complete perovskite solar cell.The structure of a single battery is CF/P3HT/MASn I_3-xCl_x-C₆₁-PVP/Ag.The solar yarn not only has outstanding photovoltaic performance,PCE reached 7.49%.