Solvent-free solution processed passivation layer for improved long-term stability of organic field-effect transistors

Abstract

In an effort to realize organic field-effect transistors (OFETs) that are stable over long periods of time, we have designed an organic-inorganic hybrid passivation material (TGD622t) prepared via a nonhydrolytic sol-gel process that does not require the use of solvents. Fourier-transform infrared spectroscopy, atomic force microscopy, and UV-visible spectroscopy demonstrated the high density and low porosity of the organic-inorganic hybrid transparent TGD622t film after low-temperature curing (below 100 degrees C). The dense TGD622t passivation layer, which exhibited a water vapor transmission rate (WVTR) of 0.434 g m(-2) per day, effectively protected the poly[9,9-dioctylfluorenyl-2,7- diyl]-co-(bithiophene)]-based OFETs from humidity and oxygen in ambient air, resulting in a much more robust OFET performance with long-term stability relative to the operation of unpassivated devices.