High‐Performance Screen‐Printed Full‐Configuration Flexible Photothermoelectric Detector Arrays Enabled by Germanium‐Incorporated Tellurium

ABSTRACT Flexible photothermoelectric (FPTE) detectors uniquely integrate broadband, self‐powered, and uncooled detection, making them promising candidates for electronic skin and wearable health monitoring. Yet, the lack of well‐matched n ‐ and p ‐type flexible thermoelectric (TE) films combining both high electrical conductivity and high Seebeck coefficient has largely confined the reported FPTE detectors to an incomplete single‐leg architecture. Herein, we found that the TE properties of p ‐type tellurium could be significantly enhanced by Ge incorporation, making Te 0.99 Ge 0.01 promising p ‐type TE materials for double‐leg FPTE detectors. By developing Te 0.99 Ge 0.01 and Ag 2 Se paste formulae, a full‐configuration FPTE detector array was fabricated on flexible polyimide substrate via a facile screen‐printing method. After a carefully designed thermal treatment process, the screen‐printed Te 0.99 Ge 0.01 and Ag 2 Se films achieved superior power factors of 2.25 µW cm −1 K −2 and 23.8 µW cm −1 K −2 , respectively. Consequently, the prepared single‐pixel FPTE detector exhibits a high responsivity of 2.49 V W −1 with low internal resistance of only 55.7 Ω, leading to an impressive detectivity of 2.38 × 10 8 Jones under 980 nm infrared (IR) radiation. The flexible detector array, assembled from single‐pixel units, showed excellent capability in mapping IR spatial distribution, underscoring the practical potential of Ge‐incorporated tellurium for flexible TE applications.