Poly (9,9-dioctylfluorene)(F8) gel with beta phase has been investigated in terms of optical absorption, photoluminescence measurements and Fourier transform infrared spectroscopy. The optical properties of the F8 gel markedly changed in the temperature range from 70 to 80 degrees C owing to the vibration of polymer chain related to the glass transition temperature of F8. F8 films by thermal printing method had the characteristic particulate morphology. Current efficiencies of polymer light emitting diodes (PLEDs) with the beta phase of F8 fabricated by the thermal printing method were better than that with the amorphous phase of F8 by the spin-coating method. We demonstrate the beta phase effects of PLEDs characteristics by the thermal printing method. (C) 2009 Elsevier B.V. All rights reserved.