High‐Sensitivity Flexible Thermocouple Sensor Arrays Via Printing and Photonic Curing

Despite remarkable advances, high-performance thermoelectric (TE) materials-based thermocouples (TCs) lack mechanical robustness and flexibility. Hence, conventional low Seebeck coefficient metals (Ni, Cu, Fe) wire-junction-based TCs are used for temperature sensor applications. However, not only the sensitivity of the metal-based TC sensor is low, but also it is very difficult to fabricate a pixelated sensor using the conventional approach. In this study, high-performance (SbBi)$_2$(TeSe)$_3$-based printed flexible TE materials are employed to fabricate two types of shape-conformable TC-based temperature sensor arrays with 25 pixels (TSA I and TSA II). Bi$_{0.5}$Sb$_{1.5}$Te$_3$-based p-type (p-BST) printed TE film and copper are used to fabricate TSA I, and the p-type film together with the Bi$_2$Te$_{2.7}$Se$_{0.3}$-based n-type (n-BT) film is used to fabricate TSA II. A high average sensitivity (S$_{exp}$) value of ≈124 µV °C$^{−1}$ for TSA I and ≈319 µV °C$^{−1}$ for TSA II is attained with high linearity.