Low-temperature templated synthesis of porous TiO2 single-crystals for solar cell applications

Abstract

A facile low-temperature synthetic method of growing semiconductor mesoporous single-crystal of anatase TiO2 directly on FTO substrate was developed. The templated hydrothermal synthesis approach was employed to make mesoporous single-crystal TiO2 that contains pores tens to hundreds of nanometres in size under low temperature, which opens a potential way to produce useful functional thin film photoanodes by one-pot approach for fabricating cheap and highly efficient optoelectronic devices. This method is based on seeded nucleation and growth inside a pre-formed mesoporous silica film template immersed in diluted precursor solution. The electrochemical characterizations showed that the directly grown mesoporous single-crystal thin film on FTO substrate has substantially higher conductivity and electron mobility than conventionally deposited TiO2 thin films by printing techniques. Hence, using the as-synthesized mesoporous single-crystal thin film baking at 150°C as photoanodes, an encouraging 5.83% solar to electricity conversion efficiency was achieved. It is expected that the developed mesoporous single-crystals on FTO substrate may find broader applications in many different technologies. This generic synthetic strategy extends the possibility of mesoporous single-crystal films directly growing to a range of substrates. Moreover, this approach could work at lower temperatures below 150°C, which could considerably minimize the environmental impact and production costs of high performance mesoporous materials.