碲化铋基柔性热电器件研究进展

Research Progress on Bismuth telluride Based Flexible Thermoelectric Devices

摘要:

碲化铋基柔性热电器件具有体积小、质量轻、可变形、可弯折的特点，能够实现高密度阵列集成，契合未来电子信息领域对高性能、微型化、低功耗器件的发展需求。该种器件适用于复杂几何结构和不规则曲率变化的表面，能够满足物联网、可穿戴设备、微电子芯片行业对微能源供应、小空间快速制冷、个人热量管理的需求。综述了近年来碲化铋基柔性热电器件研究进展和存在的问题，并对其未来的发展方向进行了展望。虽然碲化铋基柔性热电器件的研究取得了一定的进展，但整体上仍处于实验室阶段，实现大规模商用应用还有一段距离，今后应侧重于输出功率的提升、穿戴舒适性和美观性、服役稳定性和使用寿命，以及降低制造难度方面的研究。碲化铋基柔性热电器件主要分为块体型、薄膜型和纺织物型3大类型。块体型器件的输出功率一般可达1×10^-5 W?cm^-2，但其柔韧性和穿戴舒适性不足，可通过提高碲化铋基热电材料本身的ZT值、优化负载电阻、选择热导率低的封装材料，以及合理设计封装元件尺寸和热电臂的形状、数目和连接方式等方法来持续提高其热电性能，可通过开发柔韧性更高、甚至具备自愈能力的封装材料和连接材料来提升其柔韧性和穿戴舒适性。薄膜型器件的输出功率一般在1×10^-6—1×10^-9 W?cm^-2之间，还达不到实际应用需求，通过提升碲化铋基薄膜制备技术并优化工艺参数来提高薄膜本身热电性能，开发热稳定性、电阻率、导热系数更优的热电界面材料，从而降低接触热阻导致的界面热损失，提高输出功率和转换效率，通过选择柔韧性和机械稳定性更高的基底材料来其使用寿命。纺织物型器件具有较好的拉伸、弯曲和剪切性能，能满足穿戴的舒适性要求，但热电性能较差，输出功率也普遍在1×10^-6—1×10^-9 W?cm^-2之间，且稳定性不足，可通过改进涂印和浸渍工艺来提高纱线表面碲化铋基热电材料的均匀性，创新热电纱线组装的结构以在织物厚度方向上更好地建立温差，从而提高其热电性能。本研究为碲化铋基柔性热电器件的应用提供了理论参考。

Abstract:

Flexible thermoelectric devices based on bismuth telluride are compact， lightweight， and capable of high-density array integration， aligning with the future trends of high performance， miniaturization and low power consumption in electronic information devices. These devices are deformable and bendable， making them suitable for complex geometric structures and surfaces with irregular curvature changes. They are ideal for micro-energy supply， rapid cooling in small spaces， and personal thermal management in fields such as the Internet of Things， wearable devices， and micro-electronic chips. This paper reviews the recent research progress and challenges of flexible thermoelectric devices based on bismuth telluride and discusses their future development directions. Flexible thermoelectric devices based on bismuth telluride can be categorized into three types： block， film and textile. Although current research has achieved promising results， these devices are generally still in the laboratory stage and not yet ready for large-scale commercial use. Future efforts should focus on improving their output power， wear comfort and aesthetics， service stability and life， and reducing manufacturing difficulty. Block-type devices can achieve output power levels of tens of microwatts per square centimeter， but their flexibility and wearing comfort are insufficient. To enhance their thermoelectric performance， strategies including improving the ZT value of the bismuth telluride-based thermoelectric materials， matching load resistance appropriately， selecting low thermal conductivity packaging materials， rand designing package components and thermoelectric arms in terms of size， shape， number， and connection mode. Additionally， developing packaging and connection materials with higher flexibility and self-healing capabilities could increase flexibility and wear comfort. Film-type devices typically have output power in the range 1×10^-6—1×10^-9 W?cm^-2， which can not meet the practical application requirements. Improving the preparation technology of bismuth telluride-based films and optimizing the process parameters can enhance their thermoelectric properties. Developing thermoelectric interface materials with better thermal stability， resistivity and thermal conductivity can reduce the interface heat loss due to contact thermal resistance， thereby increasing output power and conversion efficiency. Using substrate materials with greater flexibility and mechanical stability can also extend their service life. Textile-type devices offer better stretching， bending and shearing properties， which meet the comfort requirements for wearables. However， their thermoelectric performance is poor， with output power generally in the range 1×10^-6—1×10^-9 W?cm^-2， and their stability is inadequate. Improving the printing and dipping processes to enhance the homogeneity of the bismuth telluride-based thermoelectric materials on yarn surfaces and innovating the structure of thermoelectric yarn assemblies to better establish the temperature differences across the fabric thickness can improve their thermoelectric performance.