V2O5 Thin Films for Flexible and High Sensitivity Transparent Temperature Sensor

This work reports the optimization of V2O5 Seebeck coefficient to obtain high sensitivity and transparent temperature sensors. It is observed that the film thickness plays a major role on the thermoelectric properties, together with the annealing step, obtaining a Seebeck coefficient of -690 mu V K-1, for 75 nm thick V2O5 films deposited on glass, after an annealing step of 1 h at 773 K, in air. The V2O5 films are also deposited and optimized on polyimide substrates, but lower annealing temperature is required, 573 K for 3 h, to maintain the flexibility of the substrate and simultaneously high Seebeck coefficient, -591 mu V K-1. These films are used in a simple design sensor and tested on the surface of a microfluidic channel (500 mu m) made of polydimethylsiloxane, while having hot water flowing through it. The response time is below 1 s and the recovery time around 5 s.