Synthesis And Application Of Novel Hole Transport Materials Containing Triphenylamine Units

In this dissertation, four novel small-molecule hole transporting materials(HTMs)2TPA-n-DP (n=1,2,3,4) with a linear-conjugated structure weresynthesized, which were based on a diphenyl (DP) unit and triphenylamine (TPA)unit linked with olefinic bonds. All the compounds were characterized by infraredspectrum (IR), proton nuclear magnetic resonance (1H NMR), mass spectrum (MS)and elemental analysis (EA) technologies. The compounds showed excellentsolubility in common organic solvents such as tetrahydrofuran, chloroform,chlorobenzene, and so on.The optical, electrochemical and thermal properties as well as hole transportingmobilities were investigated comprehensively. The UV-vis spectra and PL spectra of2TPA-n-DP showed a bathochromic shift both in solution and in thin films as theexpansion of the-conjugated systems. All compounds represented solvent influence,which are consistent with Lippert-Mataga relationship.These compounds possess highglass transition temperature Tg(98~164℃) and decomposition temperature Td(367~447℃). The HOMO levels of2TPA-n-DP were in the range of-4.90and-5.00eVwhich could match with ITO (-4.70eV) and CH3NH3PbI3(-5.44eV) and are properfor hole injection. At room temperature, hole-drift mobilities of2TPA-n-DP werebetween10-5and10-4cm2V-1s-1which indicate good hole transporting abilities. Thehole transporting mobilities are arranged in this order:2TPA-1-DP>2TPA-2-DP>2TPA-3-DP>2TPA-4-DP.The amorphous, surface properties and coating methods of2TPA-n-DP organicthin films were also investigated. The film formability of these compounds could beimproved by increasing of the compound molecular weight and the expanding of theconjugated system. The properties of the spin-coating and vacuum deposited thinfilms were investigated. It is found that the stacking manner of spin-coating film isconducive to charge transport, which provides the feasibility of the application fordevices. The device of FTO/TiO2/CH3NH3PbI3/HTMs/Au based on2TPA-n-DPexhibit encouraging efficiency η of7.34%,9.10%,8.10%,7.79%, respectively.Compared to the spiro ring structure, the linear-conjugated structures of2TPA-n-DP also have excellent performance, which provide compelling evidencethat small-molecule HTMs with a linear-conjugated structure have great potentialfor the application in perovskite solar cell.