Design, Synthesis And Organic Laser Gain Media Of Pyerene, Triazine And Their Derivatives

Recently, solution-processed organic emitters with good optical and electrical properties have attracted much attention for applications organic light-emitting diodes(OLEDs) and organic lasers. To date, despite significant progress has been achieved in OLEDs and oganic lasers, electrically pumped organic lasers have not been realized yet. Thus, a search for new efficient organic emitters as organic laser gain media with superior optical and electrical properties and a better understanding of the relationship between molecular structures and device properties are highly required. Inspired by the promising characteristics of pyrene and triazine, a set of pyrene derivatives and triazine derivatives were synthesized and characterized. The relationship between molecular structures and optical and electrical properties were studied and their applications in oganic lasers were also explored. Details are as follows:(1) A set of pyrene derivatives substituted with multiple triazatruxene at 1,6- and 1,3,6,8-positions was synthesized and characterized. Their thermal, photophysical, and electrochemical properties were investigated in comprison with those of the pyrene and triazatruxene units to explore the relationship between the molecular architectures and corresponding properties. The results indicated that construction of multi-substituted triazatruxene-pyrene architectures was beneficial to improving the electrical properties and thermal stabilities without largely sacrificing the optical properties, manifesting the potential of triazatruxene-functionalized pyrenes as efficient gain media for electrically pumped organic lasers.(2) A series of multi-arm dendrimers based on triazine derivatives were synthesized and characterized. Improved the electrical properties, thermal and morphology stabilities are obtained due to construction of multi-substituted triazine architectures. Stable and efficient blue amplified spontaneous emission was observed for these dendrimers. ASE characteristics as a function of annealing temperature indicated these materials have great operational stability of the gain properties at high annealed temperature up to 200°C in open ambient atmosphere.(3) Two novel efficient deep blue emissive isomers(T-m and T-p) containing 1,3,5-triazine, carbazole and fluorene were synthesized and characterized. The isomer T-m has better electronic conjugation, higher photoluminescence quantum yield and faster decay time in which the carbazole unit and fluorene units are linked together through 2- and 7-position, while 3,6-linkage between carbazole unit and fluorene units happens in isomer T-p. The two isomers show great differences in optical and electrical properties. Remarkably, the ASE threshold for T-m is 34 nJ, while the ASE threshold for T-p is 50-fold higher than T-m. These results indicate that the oligomer T-m based on 1,3,5-triazine, carbazole and fluorene is excellent candidate material for efficient deep blue gain media.(4) A series of oligomers based on triazine derivatives substituted with diphenylamine were synthesized and characterized. Their thermal and photophysical properties were investigated in comprison with those of liner fluorene-based oligomers without triazine. The results indicate intergration of triazine unit onto fluorine-based oligomers is beneficial to improving thermal stabilities and photoluminescence quantum yields. This work offers new opportunities to design organic semiconductors with high photoluminescence quantum yields. ASE results based on these materials suggest they are good candidates for oganic lasers.