Study On Porous Electron Transport Layer In Carbon Based Fully Printed Perovskite Solar Cells

Perovskite solar cells(PSCs)is a rising star in the field of photovoltaic,rapid photoelectric conversion efficiency(PCE)improvement has been 25%,which comparable to silicon solar cells.However,this device requires precious metal as the back electrode and the insecure hole transport material(HTL),which cannot meet the requirements of commercial applications.The PCE of the device with carbon electrode and no HTL up to 16%,which has good potential.The printable devices use TiO₂ as electronic transmission layers(ETLs).This paper starts from the electron transport layer and optimizes the device from the following aspects:First,from the aspect of material selection,the device adopts SnO₂ as the support of the device and electronic transport material to replace TiO₂ material,as options for looking for metal oxide material more suitable for the electronic transport layers;Secondly,from the aspect of material synthesis and application,a kind of MOF material was synthesized as the precursor material for preparing mesoporous TiO₂,and make this new MOF-TiO₂ an ETL material.Finally,from the aspect of PSCs structure,the double-ETLs of SnO₂/TiO₂ is designed to further promote the PCE.The research contents and results are as follows:1.Take SnO₂ as porous layer material to prepare appropriate porous layer slurry and apply it to carbon based printable PSCs.Although the PCE obtained is lower than that of commercial TiO₂ materials devices,compared with similar structure devices based on SnO₂ in literature,evident promotion has been made,among which the best device photoelectric conversion efficiency can reach 8.8%.This provides a foundation for SnO₂replacement TiO₂ to become the new ETL material.2.NH₂-MIL-125 was successfully synthesized and the derived anatase TiO₂nanocrystalline was used in printable carbon-based perovskite devices.The pie morphology of TiO₂ can promote the formation of homogeneous porous layer in the screen-printing process,which is conducive to the penetration and crystallization of perovskite.In addition,another kind of TiO₂ nanocrystal was obtained from MIL-125 in the same way for comparison.As ETLs in PSCs,the two TiO₂-based devices showed higher PCE,13.49%and 12.55%,respectively.At the same time,the device has good stability.3.For better performances of devices,the two-layer ETLs of SnO₂/TiO₂ was designed.Since SnO₂ had lower conduction band and valence band than TiO₂,SnO₂/TiO₂ could transport electrons better after electron extraction,thus improving the performance of the devices.The highest PCE of 13.77%was obtained.