Laser processing of TiO 2 films for dye solar cells: a thermal, sintering, throughput and embodied energy investigation

We have analysed and optimised a laser process for the sintering of the TiO 2 layers in dye solar cells (DSCs). Through a thermographic characterisation of the process, we show that it is possible to scale and process large areas uniformly (16 cm 2 ). We fabricated DSCs with nanocrystalline (nc)‐TiO 2 films sintered by using pulsed ultraviolet laser with an average output power P varying from 1 W to 7 W whilst mainting a constant power conversion efficiency η . The highest efficiency reached for a laser sintered DSC was 7%. The time required to sinter 1 m 2 of nc‐TiO 2 film was found to decrease hyperbolically with P , which is important for determining process takt times. We quantified the embodied energy ( EE ) required to sinter 1 m 2 of the active TiO 2 layer for a variety of different processes, and found that the EE for the laser sintering process with a system wall plug efficiency of 3.5% to be competitive with the more conventional oven and belt furnace treatments. We outline the main features required from a laser system to carry out an efficient, energetically favourable and industrially applicable automated process with competitive throughput. Copyright © 2012 John Wiley & Sons, Ltd.