Side Chain Effect Of Wide Bandgap Oligofluorenes On ASE And Lasing

The complexity of the molecular structure is the primary cause of the failure of electrical pumping organic laser.So far,the contradictory relationship between mobility,luminescence and device stability has not been resolved.Hence,it is significant to explore the molecular structure deeply,especially the type of substituents,the number and size of substituents.Based on the research of luminescence of oligofluorescenes,a series of comparable wide bandgap blue oligofluorescenes were designed to investigate the ASE,gain and lasing properties.The details are as follows:?1?In order to study the subsituent effect of the side chain on ASE and stimulated emission of oligofluorescenes,the photophysisc,ASE and lasing performance of three terfluorenes containing sulfone,including DOF-SFXSO,DOPhF-SFXSO and DOSFX-SFXSO were measured.The value of2.11?J/cm² of the ASE threshold and 76.0 cm^-1of the gain coefficient were exhibited in the film of terfluorene DOSFX-SFXSO with the group of OSFX.The results suggest that OSFX as the substituent of the side chain is better than OPhF and OF.?2?To explain the influence of the changes in spiro units on the ASE and lasing properties of oligofluorenscenes,the photophysisc,ASE and lasing performance of four compounds DSFX-OSFX,DSBF-OSFX,DOSFX-SFX and DOSFX-SBF based on SFX and SBF group were examined.The threshold of one-dimensional DFB lasing of DOSFX-SBF was 0.85?J/cm²,which shows SBF is excellent than SFX as the monomer of lasing gain medium.?3?Exploring the relationship of the hindrance functionalization and the ASE and lasing properties of oligofluorenscenes,the photophysisc,ASE and lasing performance of SFX-TOSFX,SBF-3SFX and SBF-TOSFX were investigated.It is beneficial for the ASE and thermal stability of oligofluorenscenes to increase the steric hindrance.The ASE threshold of the film of SBF-TOSFX was 0.31?J/cm² and the value with 9.4?J/cm² was obtained from the film when the annealing to280?.