Synthesis Of Organic Hole Transporting Materials Based On BINOL For Perovskite Solar Cells

Nowadays the world is suffering in the energy and environment crisis.Solar energy has attracted scientists' attention because of its huge energy supply.Perovskite solar cells have gained significant attention for their easy access to raw materials and ease of fabrication.The hole transport layer is the current research focus which is an important part of the perovskite cells.In this thesis,we designed and synthesized a series of new type of organic small molecules replace expensive spiro-OMeTAD as a hole transporting materials.And study the photovoltaic properties of perovskite solar cells.Firstly,the design and synthesis of 3 novel organic hole transport materials(Q197,Q198,and Q205),the chemical structure and physical properties were characterized and were applied to the perovskite solar cells.the relationship between photovoltaic properties and hole transport molecular structure were studied.Found that the photovoltaic performance of the hole transport materials based on BINOL is good,open circuit voltage and photocurrent were higher than that of hole transporting materials based on biphenol,BINOL groups increased conjugation of the parent nucleus and improve the conductivity of the materials.Under the condition of reducing the content of TBP by 40%,the highest conversion efficiency was achieved by Q197,which was 8.38%,which was close to the photoelectric conversion efficiency of spiro-OMeTAD under the same conditions.In addition,Donor structure of hole transport properties is important for the photovoltaic properties of perovskite solar cells.2,7-carbazole-(4-methoxy phenyl amine)significantly increased the light current of the perovskite solar cells,3,6-carbazole(4--methoxy phenyl amine)can improve the open circuit voltage.In order to increase the solubility of the synthesis of hole transport materials and improve the film forming property,the introduction of benzyl and hexyl side chains,Q221 and Q222 have been designed and synthesized.It is found that Q221 based on the benzyl side chain have the open circuit voltage of the 945 mV and the photoelectric conversion efficiency is as high as 10.05%,which is the same as spiro-OMeTAD(10.06%)under the same condition.When the dopant(Li-TFSI and TBP)to reduce the concentration of 50%,The devices still showed good conductivity and hole transport ability,obtain higher photoelectric conversion efficiency(10.37%),better than spiro-OMeTAD.The introduction of benzyl not only improves the photovoltaic performance of the devices,but also enhances the stability of the devices.After 200 hours of continuous illumination,the photoelectric conversion efficiency of the devices only decreased 50%.