Dually Crosslinkable SiO2@Polysiloxane Core-Shell Nanoparticles for Flexible Gate Dielectric Insulators

Abstract: Hybrid gate dielectric material for flexible OTFT is developed by using core-shell nanoparticles (SiO2@PSRXL) where the core and the shell consist of silica nanoparticles and polysiloxane resin, respectively. Since polysiloxane resin contains both thermal- and photo-crosslinkable functional groups, densely-crosslinked thin gate dielectric films can be easily prepared on various substrates by conventional solution casting followed by dual crosslinking. SiO2@PSRXL films exhibit high thermal stability (weight loss at 300 ºC is smaller than 3 wt％). The dielectric films made of SiO2@PSRXL show exceptionally low leakage current and no breakdown voltage up to 4.3 MV/cm, which are comparable to those of silica dielectrics prepared by CVD. OTFT devices based on dibenzothiopheno[6,5-b:6‘,5‘-f]thieno[3,2-b]thiophene (DTBTT) as a semiconductor and SiO2@PSRXL as a gate dielectric exhibit good hole mobility (2.5 cm2/V？s) and the Ion/Ioff ratio (106).