The Synthesis, Electronical Structure And Photoelectric Properties Of Series Seven-membered Heterocycre Bridged Bipnenyl Monomers And Polymers

Up to date, Flat Panel Displays (FPDs) are playing important roles for mankindto get information and their effects are significant. Organic and polymerlight-emitting devices (OLEDs and PLEDs), the novel members of FPDs, haveattracted great attentions of the science fienld and industry for their excellentperformance. Industrialization of OLEDs and PLEDs drove the searching of new andgood-performanced organic and polymer light-emitting materials. The investigationof light-emitting materials already expand to ultraviolet light-emitting form visiblelight. Now, in the research of wide–bandgap semiconductor, inorganicsemiconducting materials had obtained outstanding success. They have wideapplication foreground in visible light solid display, high-density storage, ultravioletdetect and economy energy illuminance fields. Though the research onorganic/polymer luminescence materials with wide– bandgap is lag compared withinorganic materials, wide–bandgap organic /polymer materials will become theresearch focus in the world. In this paper, the monomers of seven-membered heterocycre bridged biphenylwere designed and synthesized and researched by X-ray crystallography andmolecular force field simulation, which proved that the monomers had only stablespace conformation and the twisted angle of the monomer is about 40o. Theabsorption data n indicated that maximal absorption peak is between planar fluorenemolecule's absorption peak and benzene's. The twisted angle of the two benzenesonly partly break the conjugation of biphenyl.The seven-membered heterocycre bridged biphenyl can be applied to modify theconjugated polymer. Alternating copolymer (PDHFSCDH) consisted of fluorene andseven-membered heterocycre bridged biphenyl showed high-efficient UVlight-emitting, and its bandgap increased 0.29 eV comparing with polyfuorene with - iii -中英文摘要 吉林大学博士学位论文C6 substituents at C-9(PDHF). Alternating copolymer (MEHSCD-PPV) composed ofseven-membered heterocycre bridged biphenyl and m-phenylene vinylene exhibitedhigh-efficient blue light-emitting, and its absoption and emission peaks blue shift100nm compared with MEH-PPV. The homopolymers (P1 and P2) parepared from the seven-memberedheterocycre bridged biphenyl monomer exhibited both UV photoluminescence andUV elctroluminescence. The X-ray crystallography and molecule model calculationinvestigation of model compound D1 of polymer ( P1) presences two differentconformation in one polymer chain (planar and twisted conformation). Here, planarbiphenyl conformation with low energy is the emitting center. The lesscommunication between two segments is likely corresponding to the effect ofemission spectra of solution strongly depended on the excitation energy. Theintrachain migration of the excitons may be limited by broken conjugation in PMPdue to the local twisting and meta-link sites in PMP chain. In the solid film, the lessdependence of the emission intensity on excitation wavelength indicates the presenceof direct interchain exciton energy transfer between two energy species. And theX-ray crystallography investigation of model compound D1 also exhibited apresence of peculiar hydrogen bonding, which is the driving force to form planarconformation. The twisted polymer P3 with similar structure was also studied. Itexhibited the same conformation character and photoluminescence property. Theresearch on electroluminescence devices indicated that itsEL emission is peaked at456nm. In this paper a series of monomers with novel structure were designed, and thepolymers and oligmers have wide-bandgap emission were synthesizedand thedevices based on them were invested . It is the first time that organic/polymer UVlight-emitting electroluminescence was observed at room temperature, which can be - iv -...