Spectral investigation and laser action in solid films of fluorene-dibenzothiophene-s,s-dioxide co-polymers

A systematic optical study of a series of 9,9–dyoctylefluorene-2,7-diyl-dibenzothiophene-s,-s-dioxide-3,7-diyl co-polymers p(F-S)y has been performed where S unit (-dibenzothiophene-s,sdioxide-3,7diyl) varied from 15 to 50 mol%. We have investigated optical absorption, steady state and time resolved photoluminescence spectroscopy at room temperature and at low temperature. The emission band for all of these materials is red shifted from that of poly(9,9-dioctylfluorene). Except for p(F-S)50 all our material show one phosphorescence band at low temperature. Dual phosphorescence is observed for p(F-S)50 that are originated from different monomer units. Drop cast film of p(F-S)50 shows amplified spontaneous emission (ASE) effect peaking at 2.66 eV with FWHM at 5 nm.