Solid‐State Electrochemical Thermal Transistors

• Published in: Advanced functional materials Vol. 33; no. 19
• Main Authors: Yang, Qian, Cho, Hai Jun, Bian, Zhiping, Yoshimura, Mitsuki, Lee, Joonhyuk, Jeen, Hyoungjeen, Lin, Jinghuang, Wei, Jiake, Feng, Bin, Ikuhara, Yuichi, Ohta, Hiromichi
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 08.05.2023
• Subjects: Crystal defects; Crystal structure; electrochemistry; Electrodes; Heat transfer; Heat transmission; Logic circuits; Materials science; Multilayers; Perovskites; redox treatment; Semiconductor devices; Solid electrolytes; solid state; Thermal conductivity; Thermal management; thermal transistors; Transistors; transition metal oxides
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202214939

Thermal transistors that electrically control heat flow have attracted growing attention as thermal management devices and phonon logic circuits. Although several thermal transistors are demonstrated, the use of liquid electrolytes may limit the application from the viewpoint of reliability or liquid leakage. Herein, a solid‐state thermal transistor that can electrochemically control the heat flow with an on‐to‐off ratio of the thermal conductivity (κ) of ≈4 without using any liquid is demonstrated. The thermal transistor is a multilayer film composed of an upper electrode, strontium cobaltite (SrCoOx), solid electrolyte, and bottom electrode. An electrochemical redox treatment at 280 °C in air repeatedly modulates the crystal structure and κ of the SrCoOx layer. The fully oxidized perovskite‐structured SrCoO3 layer shows a high κ ≈3 .8 W m−1 K−1, whereas the fully reduced defect perovskite‐structured SrCoO2 layer shows a low κ ≈ 0.95 W m−1 K−1. The present solid‐state electrochemical thermal transistor may become next‐generation devices toward future thermal management technology. Solid‐state thermal transistor that controls heat flow with an on‐to‐off ratio of the thermal conductivity ≈4 without using any liquid is demonstrated. Upon turn on and off the thermal transistor by the electrochemical redox treatment in air, the crystal structure and the thermal conductivity of the SrCoOx layer are repeatedly modulated. This boosts solid‐state thermal transistor development.