Heat sink assisted elevated temperature sintering process of TiO2 on polymer substrates for producing high performance flexible dye-sensitized solar cells

Abstract

We report a plate fin heat sink assisted elevated temperature sintering of TiO2 pastes doctor-bladed onto the indium tin oxide coated polyethylene terephthalate (ITO PET) substrates to function as photoanodes in the fabrications of flexible dye sensitized solar cells (DSSCs). In this process, sintering through a convective heat transfer has been employed to heat the pastes of TiO2 nanoparticles and its composite coated onto the ITO PET substrates at an elevated temperature up to 250 °C without the thermal decomposition and loss of integrity of PET polymer and then used in the preparation of flexible DSSC photoanodes. The TiO2 composite flexible photoanode in the DSSCs has produced a maximum power conversion efficiency (PCE) of 4.11 ± 0.32 % with an open circuit voltage (Voc) of 0.77 V. These values are found higher than the PCE and Voc values reported for the ITO PET based flexible DSSCs processed by various high pressure compression methods. Besides, the mechanical stability studies of flexible DSSC photoanodes prepared by this method have shown only less than 9 % decrease in the PCE values after 30 bending cycles, indicating good mechanical stability and adhesion between the TiO2 films and ITO PET substrates.