Design,Synthesis And Photoelectric Properties Of Optoelectronic Materials Based On Conjugated Pyrene And PDI

Among all kinds of organic optoelectronic materials,planar conjugated organic molecules have been widely investigated by researchers in recent years because of their unique optoelectronic properties.In general,most of the aromatic rings in organic optoelectronic materials are connected by carbon-carbon single bonds,and the aromatic rings have certain angles because of the distribution of electron clouds,so the molecular main chain structure is non-planar,that is,one-dimensional or three-dimensional structures.The molecular main chain of planar conjugated macromolecules is composed of continuous ring structures.The spatial structure of the main chain is two-dimensional plane,which can greatly improve the charge mobility and molecular aggregation of materials.Since the main chain is too rigid,and thus too easy to accumulate,light quenching generally occurs to reduce the fluorescence quantum yield?PLQY?.Meanwhile,they are easy to crystallize and the film-forming property is relatively poor,which is not conducive to dissolution and processing.In the previous work of our group,we constructed dendrimeric iridium complexed structures to inhibit the aggregation of the materials,which played a key role to reduce the light quenching,increase the solubility of the materials.The introduction of steric hindrance unit can break the conjugation effect and maintain the luminous color coordinates of the materials.The results show that the introduction of steric hindrance structural units can obviously improve the solution processability and film-forming properties of materials,and thus enhance the optoelectronic properties of materials,which appears as an effective optoelectronic material design strategy.Based on the results,we herein developed a set of promising conjugated molecules based on large planar conjugated units such as pyrene and perylene diimide?PDI?units with excellent optoelectronic properties.The resulting optoelectronic properties of the materials have been further improved by introducing dendrimer structures and varying the spatial configuration of the materials,which result in much enhanced electroluminescence and lasing performance.In the first chapter,using pyrene as the core,a series of pyrene derivatives were designed and synthesized by connecting the dendritic units with benzene alkoxy chains.It was found that the introduction of four side chains with methyl dendrimers significantly blue-shifted the luminescence of the materials.The materials are used as organic laser gain media,in which Py-4L showed amplified spontaneous emission?ASE?phenomenon.The material exhibited excellent the photothermal stability.The threshold of the material was recorded as 26.73?J/cm² with high gain of60.3 cm^-1 and low loss of 6.1 cm^-1.In the second chapter,a set of V-shaped conjugated molecules were designed and synthesized based on perylene diimide?PDI?units.By connecting two PDI nitrogen sites with the same benzene ring and varying the connection positions?ortho-position,meta-position and para-position?,we obtained V-shaped optoelectronic materials with different angles.It was found that varying the angle of the resulting V-shaped conjugated molecules showed an obvious effect on the aggregation of the materials.The energy transfer process between the host and the guest by doping it with the light-emitting polymer gain F8BT was further investigated,which shed light on the design and synthesis of novel organic laser gain media based on PDI units for optoelectronics.