Effects Of Regulation On The SnO₂ Electron Transport Layer With Biomolecules For Efficient Perovskite Solar Cells

At present,solar cells are mainly divided into silicon-based solar cells,multi-compound solar cells and novel thin-film solar cells.The novel thin-film solar cells mainly include perovskite solar cells,dye-sensitized solar cells and quantum dot solar cells.Among them,perovskite solar cells have been widely concerned by researchers due to their simple preparation process and low cost.In the past 13 years,the photoelectric conversion efficiency（PCE）of the perovskite solar cells has been rapidly improved from3.81%to 25.7%.Effective charge transfer between the high-quality perovskite film and the perovskite interface is necessary to obtain high-performance perovskite solar cells.Among them,tin dioxide（SnO₂）has many advantages as the most promising electron transport layer material,such as;High electron mobility,high transmittance,wide band gap,etc.,but they still have defects such as;Surface defects,internal defects,external defects,etc.Natural biofunctional molecules have a variety of special functional groups,have excellent affinity with SnO₂,and are also able to regulate the deposition of perovskite thin films.Therefore,it can be used to modify SnO₂and improve the photoelectric conversion efficiency and stability of the device.In this paper,preparing efficient perovskite solar cells by regulating SnO₂electron transport layer mainly carry out the following works.（1）The SnO₂electron transport layer was modifid by using vitamin B₁₂.Vitamin B₁₂is a cobalt-containing tetrapyrrole macromolecule with a highly conserved structure.The phosphate and repeat amide groups of vitamin B₁₂can fill various trap sites at the interface between SnO₂and perovskite simultaneously,thus crystalline perovskite films with low trap density,reducing non-radiative recombination,and enhancing carrier transport.The work function of the SnO₂film modified with vitamin B₁₂is changed,which also improves the crystallinity of perovskite and can effectively passivate the interface defects.Therefore,both the PCE and the stability of the perovskite solar cells have been significantly improved.Modification of the SnO₂electron transport layer by vitamin B₁₂provides a new method for preparing efficient and stable perovskite solar cells.（2）The SnO₂interface was modified by D-biotin to reduce the defects on the surface of tin dioxide and improve the surface infiltration and the crystallinity of perovskite film.Because D-biotin blunted the defect in the interface between FAPb I₃and SnO₂,the Schottky complex and hysteresis effects were inhibited.After D-biotin modification,the photoelectric conversion efficiency of perovskite solar cells has been increased from 18.94%to 21.00%,and the stability has also been significantly improved.