Size-tunable TiO2 nanocrystals from titanium (IV) bis (ammonium lactato) dihydroxide and towards enhance the performance of dye-sensitized solar cells

•The anatase TiO2 sol with a crystallite size of 3.0 nm was prepared.•Both TiO2 sol and titanium (IV) bis (ammonium lactato) dihydroxide were successfully used towards size-tunable anatase TiO2 nanocrystals.•The DSSC with an efficiency of 9.3% was archived by combining of TiO2 nanocrystals and sol treatment.•Improved interfacial contact was responsible to the performance enhancement of DSSCs.

Titanium (IV) bis (ammonium lactato) dihydroxide (TALH) was employed to prepare anatase TiO2 sol where titania in a crystallite size of 3 nm. Both the sol and TALH solution were further subjected to be hydrothermal treated at 200 °C to grow the crystallite size be most appropriate for the photoanodes of dye-sensitized solar cells (DSSCs). The DSSCs with photoanodes derived from the sol-hydrothermal TiO2 exhibited the overall energy conversion efficiency (η) of 7.8%, while the DSSCs with photoanodes derived from the TALH direct hydrothermal (DH) showed a higher η of 8.9%. Moreover, the as-prepared anatase TiO2 sol prior to the hydrothermal treatment was used as substitute for TiCl4 solution to modify the porous DH TiO2 photoanodes, and the DSSCs achieved overall energy conversion efficiency as high as of 9.3%, due to the extremely fine anatase nanocrystals in the TiO2 sol improved the connection between the TiO2 nanocrystals more significantly compared to the TiCl4 treatment.

Graphical abstractTiO2 nanocrystals derived from aqueous TALH were fabricated as the photoanodes of DSSCs, which gained efficiency as high as 9.3%.Figure optionsDownload full-size imageDownload as PowerPoint slide