High performance FTO films enabled by surfactants-directed micellar engineering

Although FTO films exhibit the coexistence of electrical conductivity and optical transparency, the pursuit of even more superior performance remains the pivotal objective for next-generation photovoltaic architectures. Element doping merely increase the carrier concentration, leading to an increase in impurity ion scattering, which results in a deterioration of mobility and optical transmittance. This paper reports a new method that introducing cationic surfactants to form micellar templates, which alters the sol-gel process of the precursor solution, increases the grain size and promotes the oriented growth of fluorine-doped tin oxide (FTO) film. The FTO films grown by spray pyrolysis with the addition of hexadecyl trimethyl ammonium chloride (CTAC) possesses higher mobility and figure of merit than original FTO film. The FTO film fabricated with the addition of 0.1 g CTAC exhibits the optimum performance, delivering a high carrier mobility of 24.4 cm 2 ·V −1 ·s −1 and a reduced sheet resistance of 9.8 Ω/sq. The calculated figure of merit reaches 3.91 × 10 −2 Ω −1 , representing a 30.7% enhancement compared to the pristine FTO film.