[8p-E203-1~15] 9.4 Thermoelectric conversion

2:15 PM - 2:30 PM JST(5:15 AM - 5:30 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[8p-E203-4] CuO@α-Fe₂O₃ Nanotubes for Improved Semiconductor-Sensitized Thermal Cell via Mid-Gap State-Assisted Charge Transfer

〇(DC)XIAOYAN SUN¹, Yoshihiro Gohda¹, SACHIKO MATSUSHITA^1,2 (1.Science Tokyo, 2.elleThermo, Ltd)

Keywords:

Semiconductor-Sensitized Thermal Cell,Heterojunction,mid-gap states

In this research, we aim to enhance the performance of semiconductor-sensitized thermal cells (STCs), a new technology capable of directly converting low-temperature waste heat into electricity. Although STCs exhibit unique behaviors such as recovery time and re-discharge, their efficiency has been limited by slow thermally excited carrier transport and interfacial recombination. To overcome these issues, we developed a pn-junction nanotube electrode and demonstrated that interfacial mid-gap states generated at the interface effectively lower the activation barrier for carrier excitation. The Cu–CuO@α-Fe₂O₃ cell achieved an open-circuit voltage of 0.55 V and a short-circuit current density of 46.40 μA/cm² at 40 ℃, maintaining stable operation for over 120 cycles. The introduction of the pn junction generated a built-in electric field at the interface, effectively suppressing electron–hole recombination and significantly improving V_oc compared with the Cu–CuO electrode. DFT calculations further revealed the formation of mid-gap states at the Cu–CuO@α-Fe₂O₃ interface, consistent with the experimentally observed decrease in activation energy from 24 to 16 kJ/mol and the 2.2-fold increase in current density.