To fabricate applicable devices, the functional nanoscale components need to be assembled in a micro- or macro-scale. This requires feasible and economic nanoengineering approaches. One of the efforts toward this goal is direct synthesis or assembly of macro-scaled complex architectures, such as arrays, networks or hierarchical structures, which are composed of well defined nanostructures.

In a systematic study that was recently published in Nanotechnology it was found that a centimetre-scale Bi2S3 nanowire network film is synthesized by a facile hydrothermal method and can be easily tape-transferred and further used to fabricate an optical switch array.

The interconnected Bi2S3 nanowire network, which is composed of large quantity nanowires with widths of 60–200 nm and lengths of several microns, was first synthesized on a Teflon foil by a hydrothermal process. By placing the obtained Teflon foil with a black film on a plastic tape and removing the foil, the centimetre-scale film was easily printed onto the plastic substrate. Thick-film screen-printing technology was used to fabricate an optical switch array, in which the commercial silver paste was printed on the Bi2S3 film to form an electrode array by using a semi-automatic screen printer.

The Bi2S3 nanowire network has a pronounced increase in conductance upon exposure to visible light with different wavelengths and possesses a very fast response time of about 2 ms. A dark conductivity of ~8.27 × 10–3 S/cm of the nanowire network was obtained from calculation of the experimental data. The conductivity rapidly increased by 24 times upon exposure to a 2.03 mW/cm2 white light. This work provides a simple and economical method to fabricate high-performance optical switch arrays and could render great potential for a low cost, mass manufacturing process.