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 degrees 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 degrees C, which could considerably minimize the environmental impact and production costs of high performance mesoporous materials. (C) 2015 Elsevier Ltd. All rights reserved.