Rubbing effect on surface morphology and thermoelectric properties of TTF–TCNQ thin films

Thin films of tetrathiofulvalene–tetracyanoquinodimethane (TTF–TCNQ), a typical organic material of charge transfer salts, were prepared on glass substrates by evaporation using TTF–TCNQ powder. The rubbing effect on the surface morphology and thermoelectric properties was studied. TTF–TCNQ films exhibited a bush-like disordered growth on the as-received glass substrate, whereas those on the rubbed glass substrate had extremely flat surfaces tiled with small rectangular TTF–TCNQ single crystals. Due to the ordered alignment of TTF–TCNQ tiles, improvement in the electrical conductivity and enhancement of the Seebeck coefficient were achieved.