Cu- or Ag-containing Bi-Sb-Te for in-line roll-to-roll patterned thin-film thermoelectrics
Xudong Tao, Qianfang Zheng, Chongyang Zeng, Harry Potter, Zheng Zhang, Joshua Ellingford, Ruy S. Bonilla, Emiliano Bilotti, Patrick S. Grant, Hazel E. Assender
Abstract
The Selective Metallization Technique shows promise for roll-to-roll in-line patterning of flexible electronics using evaporated metals, but challenges arise when applied to sputtering functional materials. This study overcomes these challenges with simultaneous sputtering of Bi-Sb-Te and evaporation of metal (Ag or Cu) for thermoelectric layers when using Selective Metallization Technique. Large-scale manufacturing is demonstrated through roll-to-roll processing of a 0.8 m wide polymer web at 25 m/min, achieving high-throughput production of functional thin-film patterns with nanometer thickness. The room-temperature-deposited material system exhibits significantly enhanced thermoelectric performance and facilitates an n-type-to-p-type transition in the Cu- or Ag-containing Bi-Sb-Te-based composite film. Here, we show that while applying Selective Metallization Technique, the evaporation of metal modifies the impact of residual oil on Bi-Sb-Te, which can be effectively removed with a few seconds of plasma exposure, and the fabricated thermoelectric devices are validated in wearable applications utilizing a coiled-up wristband design.