Laser welding of nanoparticulate TiO₂and transparent conducting oxide electrodes for highly efficient dye-sensitized solar cell

Abstract

Poor interfacial contact is often encountered in nanoparticulate film-based devices. The dye-sensitized solar cell (DSSC) is a representative case in which a nanoporous TiO(2) electrode needs to be prepared on the transparent conducting oxide (TCO)-coated glass substrate. In this study, we demonstrate that the inter-electrode contact resistance accounts for a considerable portion of the total resistance of a DSSC and its efficiency can be greatly enhanced by welding the interface with a laser. TiO(2) films formed on the TCO-coated glass substrate were irradiated with a pulsed ultraviolet laser beam at 355 nm; this transmits through the TCO and glass but is strongly absorbed by TiO(2). Electron microscopy analysis and impedance measurements showed that a thin continuous TiO(2) layer is formed at the interface as a result of the local melting of TiO(2) nanoparticles and this layer completely bridges the gap between the two electrodes, improving the current flow with a reduced contact resistance. We were able to improve the efficiency by 35-65% with this process. DSSCs fabricated using a homemade TiO(2) paste revealed an efficiency improvement from eta = 3.3% to 5.4%, and an increase from 8.2% to 11.2% was achieved with the TiO(2) electrodes made from a commercial paste.

Bioinspired High‐Adhesion Metallic Networks as Flexible Transparent Conductors

“…Fracture has been thoroughly studied in the context of tensile strain and bending etc . Recent strategies to improve the nanowire network–substrate adhesion include mechanical pressing, plasmonic laser nanowelding, nanosoldering, additional solvent treatment, polymer encapsulation, and TiO 2 gel coverage . These harsh processes cause typically some damage to the network, and therefore, strategies for simultaneous improvement of adhesion while maintaining device performance remain a challenge.…”

Improved Photovoltaic Properties Of Dye-Sensitized Solar Cells Using Laser Patterned F-Doped SnO2 Thin Films

“…In particular, improving the surface roughness with degrading the electrical properties increases the surface areas of the laser-patterned FTO thin films, enhancing their ability to be loaded with TiO 2 particles and dyes. In addition, increasing the surface roughness increases J sc and the PCE [14,18]. The PCE values of samples C-E 15.02 mA/cm 2 in sample C to 16.28 mA/cm 2 in sample E with the similar values of ff.…”

Laser Processing in the Manufacture of Dye‐Sensitized and Perovskite Solar Cell Technologies

“…A pulsed UV laser (wavelength 355 nm) was utilized in Ref. to improve the nc‐TiO 2 adhesion over the conductive substrate (Figure ). The oven‐sintered film was irradiated through the glass substrate, locally reducing the film porosity and welding the TiO 2 film to the substrate.…”