Enhanced amplified spontaneous emission by assistant Forster energy transfer in DCJTB-C545T- Alq3 coguest-host system

Amplified spontaneous emission (ASE) characteristics of a red fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H- pyran (DCJTB) were significantly improved by assistant Förster energy transfer. The coguest-host system was composed of an electron transport organic molecule tris(8-hydroxyquinoline) aluminum (Alq3) as host and a green fluorescent dye (10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro- 1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one) (C545T) as assistant dopant codoped with the guest red dye DCJTB as emitter in a matrix of polystyrene (PS). It was found that the threshold and loss were greatly reduced to 0.007 mJEpulse-1 and 7 cm-1, and the gain was significantly enhanced to 52 cm-1 by doping of C545T. The improvement of ASE performance in Alq3:C545T:DCJTB film was attributed to the energy assistant effect of C545T, leading more exciton energy to transfer to DCJTB.