Solution processable piperazine and triphenyl moiety containing non-symmetric bis-styryl-DWK type molecular glasses with light-emitting and amplified spontaneous emission properties

A series of 2,6-bis-styryl-4H-pyran-4-ylidene fragment containing glassy organic compounds with chemically stable bonding of amorphous phase promoting bulky triphenyl moieties through piperazine structural fragment (DWK-T dyes) in a form of 2-(5,5,5-triphenylpentyl)piperazin-1-yl)styryl)-substituent have been synthesized and investigated as the potential gain medium component for organic solid state laser applications. Physical properties of the dyes vary and are mostly depending from the other styryl-substituent attached to the 4H-pyran-4-ylidene backbone fragment in 6-position. Thermal stability of synthesized dyes is above 312°C with the glass transitions from 97°C to 109°C. Obtained neat spin-cast films based on these compounds exhibit photoluminescence with λ_max in range from 672 nm to 695 nm, ASE λ_max from 690 nm to 704 nm with ASE threshold values in range from 327 μJ/cm² to 1091 μJ/cm². Parameters are mostly influenced by the electron affinities of various 4-substituents in 6-styryl-fragment. The proposed synthetic approach could be useful for obtaining stable covalently bonded bulky triphenyl group containing glassy dyes while the synthetic design allows to acquire different non-symmetric 2,6-bis-styryl-4H-pyran-4-ylidene fragment containing compounds for infra-red light-emitting and light amplification systems.