Solid state amplified spontaneous emission in some spiro-type molecules:: A new concept for the design of solid state lasing molecules

Here are presented initial results on spectral narrowing in submicron thick neat films, of 2,2',7,7'-tetraphenyl-9,9'-spirobifluorene (spiro-quarterphenyl) and 2,2',7,7'-tetrakis(biphenyl-4-yl)-9,9-spirobifluorene (spiro-sexiphenyl). The luminescence effects reported here are common to several other molecules which belong the class of molecules known as the spiro-type molecules. The Amplified Spontaneous Emission (ASE) is evidenced by a dramatic collapse of the line width, when pumped with sufficient energy, down to 2.2 and 2.9 nm for spiro-quarterphenyl and spiro-sexiphenyl, respectively. These molecules have the ability to form stable, amorphous films with glass transition temperatures at around 200 degrees C. Thus, these molecules are suitable candidates as the active material in molecular solid state injection lasers.