ABSTRACT

For any thermoelectric effects to be achieved, a thermoelectric material must have hot and cold sides. Typically, the hot side can be easily obtained by excess heat. However, the passive cooling method is often limited to convective heat transfer to the surroundings. Since thermoelectric voltage is proportional to the temperature difference between the hot and cold sides, efficient passive cooling to increase the temperature gradient is of critical importance. Here, we report simultaneous harvesting of radiative cooling at the top and solar heating at the bottom to enhance the temperature gradient for a transverse thermoelectric effect which generates thermoelectric voltage perpendicular to the temperature gradient. We demonstrate this concept by using the spin Seebeck effect and confirm that the spin Seebeck device shows the highest thermoelectric voltage when both radiative cooling and solar heating are utilized. Furthermore, the device generates thermoelectric voltage even at night through radiative cooling which enables continuous energy harvesting throughout a day. Planar geometry and scalable fabrication process are advantageous for energy harvesting applications.

摘要

为了实现任何热电效应，热电材料必须具有热面和冷面。通常，热侧很容易通过过热获得。然而，被动冷却方法通常仅限于向周围环境的对流传热。由于热电电压与热侧和冷侧之间的温差成正比，因此有效的被动冷却以增加温度梯度至关重要。在这里，我们报告同时收集顶部的辐射冷却和底部的太阳能加热，以增强横向热电效应的温度梯度，产生垂直于温度梯度的热电电压。我们通过使用自旋塞贝克效应证明了这一概念，并确认自旋塞贝克装置在同时使用辐射冷却和太阳能加热时显示出最高的热电电压。此外，该设备通过辐射冷却即使在夜间也能产生热电电压，从而能够全天持续收集能量。平面几何形状和可扩展的制造工艺有利于能量收集应用。