Direct Laser Writing of Crystallized TiO2 and TiO2/Carbon Microstructures with Tunable Conductive Properties

• Published in: Advanced materials (Weinheim) Vol. 30; no. 51; pp. e1805093 - n/a
• Main Authors: Yu, Shang‐Yu, Schrodj, Gautier, Mougin, Karine, Dentzer, Joseph, Malval, Jean‐Pierre, Zan, Hsiao‐Wen, Soppera, Olivier, Spangenberg, Arnaud
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-12-2018
• Subjects: Carbon; conductive micropatterns; Crosslinking; Crystallization; Direct laser writing; femtosecond direct laser writing; functional metal oxides; Graphitization; Infrared lasers; Lasers; miniaturized pressure sensors; Nanocomposites; Optical properties; Optoelectronics; Precursors; Pressure sensors; Thin films; TiO2/carbon nanocomposites; Titanium; Titanium dioxide
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201805093

Metal oxides are an important class of materials for optoelectronic applications. In this context, developing simple and versatile processes for integrating these materials at the microscale and nanoscale has become increasingly important. One of the major remaining challenges is to control the microstructuration and electro‐optical properties in a single step. It is shown here that near‐infrared femtosecond laser irradiation can be successfully used to prepare amorphous or crystallized TiO2 microstructures in a single step using a direct laser writing (DLW) approach from a TiO2 precursor thin film doped with a suitable dye. When laser writing is conducted under a nitrogen atmosphere, simultaneous to the crosslinking of the Ti‐oxide precursor, the graphitization of the organic species embedded in the initial film is observed. In this case, a carbon network is generated within the TiO2 matrix, which significantly increases the conductivity. Moreover, the TiO2/C nanocomposite exhibits piezoresistive behavior that is used in a pressure sensor device. Using this route, it is possible to use DLW to fabricate microsized pressure sensors.
Near‐infrared femtosecond laser irradiation is successfully used to prepare amorphous and crystallized TiO2 microstructures in a single step. Under a nitrogen atmosphere, the laser‐induced graphitization of the organic species generates a carbon network within the TiO2 matrix, which significantly increases the conductivity. Moreover, the TiO2/C nanocomposite exhibits piezoresistive behavior that is used in a pressure‐sensor device.