Candle soot-enhanced pyroelectric generator for thermal energy harvesting and self-powered sensing

In recent years, there has been considerable interest in surface engineering using carbon-based coatings to improve pyroelectric performance. This work demonstrates a straightforward, economical method for a pyroelectric energy generator (PEG) using candle soot as a light-absorbing coating on a widely available PZT-based piezoelectric buzzer. Infrared (IR) lamp-induced thermal excitation was used to comprehensively assess the performance of the soot-coated and pristine PZT piezoelectric buzzer disk. Due to improved photothermal conversion, the coated PEG device exhibits a significant increase in electrical output. When exposed to the IR lamp, the short-circuit current reached approximately 204 nA, while the open-circuit voltage was approximately 4.8 V. Furthermore, under controlled thermal cycling, the device exhibited adjustable output and efficient energy storage. Further, the PEG was shown to be sensitive to temperature changes caused by human activity or the daily use of appliances, as well as to energy harvesting, suggesting its potential for self-powered sensing applications, such as breath monitoring, or converting energy from everyday appliances. Overall, this study presents a simple method to increase pyroelectric device performance efficiency in sensing and sustainable energy applications.