Preparation of nanoporous TiO2 films for DSSC application by a rapid atmospheric pressure plasma jet sintering process

We investigate the nanoporous TiO2 films sintered by atmospheric pressure plasma jets (APPJs) and their applications as photoanodes of dye-sensitized solar cells (DSSCs). A 30-s APPJ-sintered nanoporous TiO2 layer exhibits an additional absorption band between 400 and 500 nm in wavelength, attributed to incomplete removal of the organic solvents in the pastes. For TiO2 layers sintered by APPJs for 60 s and beyond, the absorption spectra are nearly identical to those of a conventional 15 min, 510 °C calcined sample. The XRD and XPS results indicate similar characteristics for APPJ-sintered and furnace-sintered TiO2 films. A DSSC with a 30-s APPJ-sintered TiO2 photoanode shows poor cell efficiency with an extremely large TiO2/dye/electrolyte electron transport interfacial resistance and a short carrier lifetime. As the APPJ treatment time reaches 60 s and beyond, the power conversion efficiencies become comparable to that of a sample with a 510 °C conventionally calcined TiO2 photoanode. Our experimental results verify that a 60-s APPJ sintering process is sufficient to replace a conventional 15 min, 510 °C furnace calcination process for TiO2 photoanodes of DSSCs. The ultra-short sintering process is made possible by the synergistic effect of the temperature and the reactivity of the APPJ, which can lower the fabrication cost.

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► Atmospheric pressure plasma jet (APPJ) sintered nanoporous TiO2 layers are studied.
► 60-s APPJ sintering can replace conventional 15 min, 510 °C calcination of TiO2.
► The DSSCs with APPJ sintered TiO2 photoanodes exhibit comparable cell efficiency.