Performance of Thermoelectric Power-Generation System for Sufficient Recovery and Reuse of Heat Accumulated at Cold Side of TEG with Water-Cooling Energy Exchange Circuit

Aiming to reduce thermal energy loss at the cold side of a thermoelectric generator (TEG) module during thermoelectric conversion, a thermoelectric energy conversion system for heat recovery with a water-cooling energy exchange circuit was devised. The water-cooling energy exchange circuit realized sufficient recovery and reuse of heat accumulated at the cold side of the TEG, reduced the danger of heat accumulation, improved the stability and output capacity of thermoelectric conversion, and provided a low-cost and high-yield energy conversion strategy in energy conversion and utilization. Through the control variable method to adjust the heat generation of the heat source in the thermoelectric conversion, critical parameters (e.g., inner resistance of the TEG, temperatures of thermoelectric modules, temperature differences, output current, voltage, power, and efficiency of thermoelectric conversion) were analyzed and discussed. After using the control variable method to change the ratio of load resistance and internal resistance, the impacts of the ratio of load resistance to inner resistance of the TEG on the entire energy conversion process were elaborated. The results showed that the maximum value of output reached 397.47 mV with a current of 105.56 mA, power of 41.96 mW, and energy conversion efficiency of 1.16%. The power density of the TEG module is 26.225 W/m2. The stability and practicality of the system with a water-cooling energy exchange circuit were demonstrated, providing an effective strategy for the recovery and utilization of heat energy loss in the thermoelectric conversion process.

Fullerene/layered antiferromagnetic reconstructed spinterface: Subsurface layer dominates molecular orbitals' spin-split and large induced magnetic moment

The interfaces between organic molecules and magnetic metals have gained increasing interest for both fundamental reasons and applications. Among them, the C₆₀/layered antiferromagnetic (AFM) interfaces have been studied only for C₆₀ bonded to the outermost ferromagnetic layer [S. L. Kawahara et al., Nano Lett. 12, 4558 (2012) and D. Li et al., Phys. Rev. B 93, 085425 (2016)]. Here, via density functional theory calculations combined with evidence from the literature, we demonstrate that C₆₀ adsorption can reconstruct the layered-AFM Cr(001) surface at elevated annealing temperatures so that C₆₀ bonds to both the outermost and the subsurface Cr layers in opposite spin directions. Surface reconstruction drastically changes the adsorbed molecule spintronic properties: (1) the spin-split p-d hybridization involves multi-orbitals of C₆₀ and top two layers of Cr with opposite spin-polarization, (2) the subsurface Cr atom dominates the C₆₀ electronic properties, and (3) the reconstruction induces a large magnetic moment of 0.58 μ_B in C₆₀ as a synergistic effect of the top two Cr layers. The induced magnetic moment in C₆₀ can be explained by the magnetic direct-exchange mechanism, which can be generalized to other C₆₀/magnetic metal systems. Understanding these complex hybridization behaviors is a crucial step for molecular spintronic applications.