posted on 2012-07-25, 00:00authored bySebastian Lacher, Naoki Obata, Shyh-Chyang Luo, Yutaka Matsuo, Bo Zhu, Hsiao-hua Yu, Eiichi Nakamura
A new class of conductive polyelectrolyte films with
tunable work
function and hydrophobicity has been developed for the anode buffer
layer in organic electronic devices. The work function of these films
featuring a copolymer of ethylenedioxythiophene (EDOT), and its functionalized
analogues were found to be easily tunable over a range of almost 1
eV and reach values as high as those of PEDOT:PSS. The new buffer
material does not need the addition of any insulating or acidic material
that might limit the film conductivity or device lifetime. Organic
photovoltaic devices built with these films showed improved open-circuit
voltage over those of the known PSS-free conductive EDOT-based polymers
with values as high as that obtained for PEDOT:PSS. Furthermore, the
surface hydrophobicity of these new copolymer films was found to be
sensitive to the chemical groups attached to the polymer backbone,
offering an attractive method for surface energy tuning.