Near Infrared Radiation as a Rapid Heating Technique for TiO2 Films on Glass Mounted Dye-Sensitized Solar Cells

Abstract

Near infrared radiation (NIR) has been used to enable the sintering of TiO2 films on fluorine-doped tin oxide (FTO) glass in 12.5 s. The 9 µm thick TiO2 films were constructed into working electrodes for dye-sensitized solar cells (DSCs) achieving similar photovoltaic performance to TiO2 films prepared by heating for 30 min in a convection oven. The ability of the FTO glass to heat upon 12.5 s exposure of NIR radiation was measured using an IR camera and demonstrated a peak temperature of 680°C; glass without the 600 nm FTO layer reached 350°C under identical conditions. In a typical DSC heating step, a TiO2 based paste is heated until the polymeric binder is removed leaving a mesoporous film. The weight loss associated with this step, as measured using thermogravimetric analysis, has been used to assess the efficacy of the FTO glass to heat sufficiently. Heat induced interparticle connectivity in the TiO2 film has also been assessed using optoelectronic transient measurements that can identify electron lifetime through the TiO2 film. An NIR treated device produced in 12.5 seconds shows comparable binder removal, electron lifetime, and efficiency to a device manufactured over 30 minutes in a conventional oven.