Aravindhan A., Glinsek S., Granzow T., Song L., Nouchokgwe Y., Kovacova V., Defay E.
Ceramics International, vol. 51, n° 25PC, pp. 47264-47271, 2025
In this study, we investigate the non-linear pyroelectric energy conversion potential of titanium doped lead scandium tantalate Pb(Sc<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub>(x = 0, 0.05 and 0.1) thin films on c-sapphire substrates using the sol-gel technique. Doping with Ti<sup>4+</sup>ions increased the transition temperature from 30 °C (x = 0) to 85 °C (x = 0.1). Indirect measurements using the Olsen cycle indicate that Pb(Sc<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub>thin films, with x = 0.05 and 0.1, yield energy densities of 2.5 and 3.06 J cm<sup>−3</sup>, respectively. Additionally, they reach up to 30 % and 18 % of Carnot efficiency, respectively, for a 10 K temperature span close to their transition temperatures. Furthermore, these doped films could be incorporated in a multi-stage device to expand the harvesting temperature range and enhance the performance of the device. A 27 % increase in energy output is calculated for a three-stage device using Pb(Sc<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub>(x = 0, 0.05, and 0.1) compared to a similar device consisting of undoped thin films (x = 0) under identical electrical and thermal cycling conditions. These results highlight the potential of Pb(Sc<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub>thin films and show promise for developing Pb(Sc<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub>multilayer capacitors to realize macroscopic multi-material cascade devices with varying transition temperatures for efficient thermal energy harvesting in the future.
