A new Te/Ag planar heterojunction device based on screen printing for boosting photothermoelectric performance and heat-source-free non-contact sensing

A flexible Te/Ag planar heterojunction (TS) photothermoelectric (PTE) film was successfully fabricated using screen-printing technology for efficient energy conversion applications. The developed TS film exhibits excellent flexibility and a remarkably high Seebeck coefficient, making it particularly suitable for PTE power generation and non-contact sensing applications. The p-type Te semiconductor component demonstrates a high value of 355 μV/K. The TS film exhibits distinct power-dependent photovoltage generation characteristics. Under 808 nm laser irradiation, the output voltage increases progressively with incident power, reaching values of 16.3, 19.3, 21.6, and 22.5 mV at corresponding power levels of 19, 22, 25 and 27 mW, respectively. Notably, at 19 mW irradiation, the photoelectric-to-total voltage ratio peaks at 93.4%, with excellent stability maintained during prolonged laser exposure tests. The effective wind velocity detection range of the sensor is 0.29–1.80 m/s. The TS film's heat-source-free non-contact sensing capability enables human behavior detection and Morse code recognition by virtue of temperature fluctuations caused by wind velocity. These unique properties in both heat-source-free non-contact sensing and PTE power generation offer promising opportunities for advancing flexible electronics and wearable technologies.