Co-Assembly Of Organic Semiconductors At The Two-dimensional Interface

The interface organic semiconductor nanostructure and properties are closely related to the performance of semiconductor electronic devices.The research of surface/interface organic semiconductor system can provide experimental and theoretical basis for revealing and understanding molecular interaction mechanism,and provide guidance for designing organic semiconductor materials or devices with excellent performance.This thesis mainly uses techniques such as Scanning Tunneling Microscope to invis the self-assembly behavior of organic semiconductor molecules at the two-dimensional interface.Based on the study of oligothiophene solution assembly,the gas-liquid interface self-assembly of polyphenylacetylene polymers was explored,and the solid-liquid interface two-dimensional crystallization behavior of n-type fused ring aromatic imide derivatives was further studied.The research content is divided into the following four parts:1.The assembly of peptide-tetrathiophene-peptide(PTP)has been investigated in solvents.By changing the ratio of mixed solvents to change the polarity of the solvent,the influence of the polarity of the solvent on the assembly structure and properties was explored.The study found that PTP can form fibers in THF / hexane solution(40-80% v hexane).This fiber exists stably and does not change with time.On the other hand,PTP forms two ordered nanostructures of vesicles and parallelograms when the water content in the THF / water(40%-60% v water).The parallelogram can be transformed into vesicles over time.The fibers exhibit supramolecular chirality which not possessed in vesicles and parallelograms.The research on the assembly mechanism of the solution system provides the research basis and reference for the research of the two-dimensional interface assembly.2.The self-assembly behavior of three polyphenylacetylene derivatives with chiral centers at the gas-liquid two-dimensional interface was explored.The purpose of the study was to compare the effects of bulk phase and two-dimensional interface on the polymer assembly structure and properties.The gas-liquid interface has a unique characteristic which is limited in two-dimension.The research found that the conformation is different from that of the solution system.Compared with the solution system,the polymer chirality is reversed or enhanced at the gas-liquid interface,which provides a new method for polymer conformation control method.3.The self-assembly behavior of three n-typed semiconductor fused ring aromatic imides PPDI,NPDI,NPNDI at the liquid-solid interface was investigated,and it was explored whether non-planar molecules with different molecular structures could form stable two-dimensional interface,and explored the relationship between molecular structure and two-dimensional nanostructure.Molecules with different conjugated structures exhibit different surface crystallization behaviors.During the assembly process,molecular symmetry has important influence on the properties of the molecular layer.It is found that too many different plane conjugated units have an adverse effect on two-dimensional assembly.The investigation has shown that non-planar conjugate structures can be ordered and self-assembled at two-dimensional interfaces.4.Co-assembly of n-/ p-semiconductor molecules at the solid-liquid interface was investigated,and the influence of p-type molecules on the two-dimensional crystallization behavior of non-planar fused ring aromatic systems were investigated.The study found that p-type molecule 1-pyrenecarboxylic acid(PCA)and n-type semiconductor molecules PPDI,NPDI,NPNDI can be co-assembled on a binary surface.Compared with single-component n-type semiconductors,PCA can promote the interface adsorption assembly of single-component large-size NPNDI,in addition,it can regulate 2D nanostructure and chirality.This study validated the feasibility of constructing two-dimensional nanostructures with non-planar semiconductor molecular interfaces.