Separation And Characterization Of The Solar Cell Acceptor PC₇₁BM

Perovskite solar cells and polymer solar cells are the most cutting-edge research objects in the field of solar cells.Fullerene and its derivatives are superior electron acceptors of solar cells because of its high electron affinity and efficient electron transport ability.PC71BM,[6,6]-phenyl-C71-butyric acid methyl ester,is the most popular electron acceptor in perovskite/polymer solar cell because of its excellent electron transport ability,broad light absorption,high solubility and low reorganization energy.However,the commercially available PC71BM is a“random”mixture of PC71BM isomers that are synthesized by traditional chemical methods in which the reactions unavoidably take place at different reactive sites of C70 to produce isomers of a,P1-PC71BM and ?2-PC71BM in an“unsteady”proportion.Due to extreme difficulties in isolation of PC71BM isomers with nearly identical structures,the efforts to separate both of ?isomers are fruitless to date.Once separating these isomers and obtaining pure isomer becomes reality,we can not only research their own physical and chemical properties of isomers themselves,but also explore the photovoltaic performance of different isomeric formulations in perovskite and polymer solar cells.So,it's significant to build the isolation system of PC71BM to accumulate enough pure isomer to explore the formulation engineer in solar cells.So far,the research on chiral acceptor materials in solar cells is less.a-PC71BM,the major isomer formed by 1,3-dipole addition to the most active double bond(a bond)of C70,is an enantiomer of two chiral isomers which can be separated through modulating the proportion of the eluent in chiral column.For distinctive acceptor PC71BM,it is meaningful to build the separation method of its chiral isomers and exploit the effect of chiral isomers on photovoltaic devices.Based on the above problems,the main works are following:(1)Synthesis,separation and characterization of three PC71BM isomers.In this thesis,the method for separating isomers whose structures are quite similar had been optimized.We also provided adequate samples for the study of formulation engineering for making efficient electron acceptors by mixing various fullerene derivatives having isomeric structures.We characterized the single crystal structures of PC71BM isomers,which provided some favorable conditions for analyzing the optimal formulation of isomeric electron acceptor from the microscopic view.(2)Effects of chiral electron transport materials on solar cell performance has been rarely reported.In this thesis,we separated a-PC71BM and obtained two chiral substances which named ?i-PC71BM and ?2-PC71BM.All target compounds have been characterized by HPLC,APCI mass spectrometry,1H and 13C NMR spectroscopy,UV-vis spectrometry and cyclic voltammetry characterization.The study provides the material conditions and experimental basis for exploring the influence of chiral electron acceptor materials on the photovoltaic performance of solar cells.