Angle-Engineered Bi0.94La0.06CuSeO Thin Films for High-Performance Transverse Thermoelectric Devices

BiCuSeO has emerged as a highly promising material for transverse thermoelectric (TTE) applications, with its performance significantly enhanced through La doping. In this study, we investigate the effect of inclination angle effect on the TTE performance of inclined Bi0.94La0.06CuSeO thin films fabricated using pulsed laser deposition technique. A record-high output voltage of 31.4 V was achieved in 10° inclined Bi0.94La0.06CuSeO film under 308 nm ultraviolet pulsed laser irradiation. Furthermore, the films exhibited significant voltage signals with excellent linearity when exposed to continuous-wave lasers across a broad spectral range (360 nm to 10600 nm) and point-like heat sources. A fundamental relationship was established, revealing that the voltage is directly proportional to sin2θ, where θ is the film inclination angle. These findings not only provide a clear optimization strategy for TTE performance through inclination angle engineering but also highlight the material’s strong potential for industrial applications, owing to its cost-effectiveness and fabrication reliability. The comprehensive understanding of the inclination angle effect presented in this work opens new avenues for the development of high-performance TTE devices, particularly for advanced optical and thermal sensing applications.