Synthesis And Photovoltaic Application Of Fluorinated Phthalocyanine/Porphyrin Complex As Hole Transport Materials’ Dopants

Organic-inorganic hybrid metal halide perovskite has excellent light absorption,wide band gap and long carrier diffusion length,which makes it outstanding in the field of solar cells.After more than ten years of rapid development,the certified photoelectric conversion efficiency of perovskite solar cells has been improved from the initial 3.8%to 25.8%,which is comparable to crystalline silicon cells,showing great commercialization potential.Nevertheless,there are still many problems in this field,which to varying degrees limit its further development on the road of commercialization.Among them,stability,as an important reference to measure the life of solar cells,has a great impact on the industrial application of perovskite,and is one of the main research directions in the field of perovskite.In this thesis,Spiro-OMeTAD hole transport layer is optimized and regulated to eliminate the introduction of hygroabsorbent dopants,in order to achieve the preparation of stable perovskite solar cells.The main contents of this thesis are as follows:1.Introducing the background of perovskite and perovskite solar cells and discussing some existing problems and main solutions of organic-inorganic metal halide perovskite solar cells.Focusing on some reported strategies to improve the stability and efficiency of cells.It is discussed from two aspects,one is the design of undoped hole transport material,the other is the design of hole transport material dopant.Based on the good hydrophobicity of fluorine substituents,a doping strategy is proposed to design a complex with hydrophobic properties to replace Li-TFSI,which can be used to regulate the hole transport materials and fabricate stable perovskite solar cells.2.Firstly,the preparation process of undoped Spiro-OMeTAD hole transport layer is optimized,and the efficiency of the device based on undoped Spiro-OMeTAD layer is improved by starting from the concentration of precursor liquid.Finally,after optimization,the photoelectric conversion efficiency of the cell device with 4000 rpm spin coating based on Spiro-OMeTAD precursor liquid with concentration of 36 mg/m L is greater than 18%,reaching the international leading level,which provides the process basis for further regulation.3.A complex substituted by hexafluorphthalocyanine is designed and synthesized.Then it is introduced into Spiro-OMeTAD as a substitute for Li-TFSI to improve the hydrophobicity of Spiro-OMeTAD layer,so as to improve the moisture resistance of perovskite solar cells and extend their service life.Phthalocyanine has been proven to have good charge transport ability and easy modification of side chains,which has the potential as an ideal dopant for hole transport materials.The experimental results show that the phthalocyanine-regulated Spiro-OMeTAD has better water stability than the lithium salt doped device,and does not have a great negative impact on the cell’s efficiency.4.The deep level and poor solubility of perfluoropphthalocyanine are not conducive to the preparation of efficient cells.In order to further optimize the regulation strategy of fluorine substituents,similar compounds,porphyrin,are selected as ligands to synthesize a series of fluoride porphyrin complexes(MP)with different central metals,which are mixed into Spiro-OMeTAD precursor solution.The experimental results show that the introduction of MP can also effectively improve the protection ability of Spiro-OMeTAD layer on perovskite layer,which is conducive to the stability improvement of perovskite solar cells.Moreover,the interaction between porphyrin molecules and perovskite layer and Spiro-OMeTAD can effectively passivate surface defects and enhance interface interaction.Improve the photoelectric conversion efficiency of devices.After excluding the negative effects caused by ion migration,the water stability and photothermal stability of MP doped Spiro-OMeTAD cells are improved in different degrees compared with lithium salt doped and undoped devices.The complex can also improve the performance of devices with P3 HT hole-transport layer.5.The main content of this paper is summarized and summarized,and the future research direction is proposed.