Synthesis And Photoelectric Properties Of Triphenylamine-azo Compounds

An effective photoinduced electron transfer arrays have become a hot spot for the long-lived charge separated state in the field of organic optoelectronic materials research,the appropriate molecular design idea and the selection of appropriate donor and acceptor groups are the key of this type of material.In this paper,a series of I-type azo-conjugated molecules have been designed and synthesized using styryltriphenylamine?indole?as the donor materials and azobenzene as the electron acceptor group.Ullmann,Vilsmer,Wittig and reduction reaction were performed and optimized to obtain the target compounds.Their intermediates and target products were all confirmed and characterized by ¹H NMR,¹³C NMR and HRMS.And the single crystal diffraction also indicated that the compounds showed the trans-structure.The spectral and electrochemical properties of I-type D-A-D compounds were investigatedusingabsorptionspectroscopy,fluorescencespectroscopy,electrochemical and theoretical calculations,The results showed that the trans-structure was stable than the cis-structure under the ground state,and the cis singlet excited state was relatively stable than trans-structure.Transient absorption spectroscopy showed that the millisecond charge separation state existed in I-type triphenylazo compoundsand the cis singlet excited state transformed into the cis structure of charge separation state.I-type D-A-D molecules were firstly used as the hole transport layer and applied for doping-free perovskite solar cell.The cell efficiencies of TPAAZO,MTPAAZO,LTPAAZO and YDAZO were 7.48%,9.02%,8.10%and 7.66%,respectively.The highest PCE of MTPAAZO was obtained as 9.02%and also the higher short-circuit current(15.96 mA?cm^-2),the open circuit voltage?917.1 mV?.The above results anticipated that the cis-structure was facilitated to form long-lived charge separated state,which was helpful to improve the photoelectric properties,the cis-configuration?V-type?triphenylamine-azo?MTPA?₂Ab was synthetized for the long-lived charge separation state in film by using absorption spectroscopy,fluorescence spectroscopy,electrochemical and theoretical calculations,The results showed that the long-lived charge separated state in film.The PCE of?MTPA?₂Ab was 2.41%?liquid DSSC?and 0.81%?sDSSC?,which proved to some extent that the design of the D-A-D structure was reasonable in the design of the organic optoelectronic material.