Highly efficient electro-optic polymers through improved poling using a thin TiO2-modified transparent electrode

A sol-gel derived thin titanium dioxide (TiO2) layer was spin-coated onto indium-tin-oxide substrate to improve poling efficiency of recently developed electro-optic (E-O) polymers. The thin TiO2 layer significantly blocks excessive charge injection and reduces the leakage current during high field poling. Ultralarge E-O coefficients, up to 160–350 pm/V at 1310 nm, have been achieved. These results show higher poling efficiency (enhancement of 26%–40%) compared to the results of poled films without the TiO2 layer. This enhancement can be explained by field distribution flattening effect at high injection barrier with the insertion of TiO2 barrier layer.