Low-temperature treatment of semiconducting interlayers for high-efficiency light-emitting diodes based on a green-emitting polyfluorene derivative
G. M. Lazzerini, F. Di Stasio, C. Fléchon, D. Caruana, F. Cacialli, (2012)
We investigate the scope for low-temperature treatment of exciton/electron blocking interlayers in light-emitting diodes based on poly(9,9’-dioctylfluorene-altbenzothiadiazole) (F8BT). We focus on poly(9,9’-dioctylfluorene-alt-N-(4-butylphenyl)-diphenylamine (TFB) interlayers processed at temperatures up to 50°C, i.e. far below the glass transition temperature of TFB (~156°C). Continuous-wave and time-resolved photoluminescence studies confirm the formation of both excitons and exciplex species, as a result of the F8BT/TFB intermixing. Interestingly, however, we can still increase the electroluminescence external quantum efficiency from 0.05% to 0.5% and 1% for progressively thicker TFB films. We propose that a degree of intermixing may become acceptable as a trade‐off to achieve low‐temperature processability.
Partners : UCL
Date of Publication : 2011/12/19
Additional Data : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=6105558