Efficient photo-thermoelectric detection by layered Bi 2+2 n O 2+2 n Se n Cl 2 superlattices with ultralow thermal conductivity

作者：Yanjiong Zhang, Yan-Feng Chen, Qiao Wen, Shining Zhu, Y. Kan, Shengdi Ta, Su-Tao Sun, Jian Zhou, Shu-Hua Yao, Yang-Yang Lv, Yanbin Chen, Cheng-Hao Yin, Hong-Tao Jiang · 发表于：AIP Publishing · 年份：2026 · DOI：10.60893/figshare.apl.c.8482695 · 研究领域：Materials science、Optoelectronics、Electronic engineering

Photo-thermoelectric (PTE) detection, consisting of photothermal and thermoelectric conversion processes, is a promising self-powered strategy for room-temperature optoelectronic sensing. However, a fundamental trade-off between electrical and thermal transport remains challenging to realize an efficient PTE effect. Herein, the theoretical calculations, based on the modified two-temperature model and thermal diffusion equation, verify that extremely low thermal conductivity along both in-plane and out-of-plane, as well as a suitable carrier concentration, can achieve excellent PTE performance. In the experiment, furthermore, as a concept-proof, layered Bi-O-Se-Cl super-lattice crystals (such as Bi 4 O 4 SeCl 2 and Bi 6 O 6 Se 2 Cl 2 ) provide an ideal platform to prove our theory, because they have the same order thermal conductivity (0.1 W·m -1 K -1 ) as that of air (0.03 W·m -1 K -1 ). Spectacularly, the Bi 6 O 6 Se 2 Cl 2 device demonstrates excellent optoelectronic detectivity at the infrared regime (responsivity of 87.29 mV·W -1 at 1550 nm, noise-equivalent power of 10.63 nW·Hz -1/2 , a detectivity of 5.64×10 6 Jones, response time of 88 ms). This superior performance comes from optimized synergetic manipulations of extremely low thermal conductivity (in- and out-of-plane thermal conductivity are 0.62 W·m -1 K -1 and 0.2 W·m -1 K -1 , respectively), and suitable carrier concentration (~10 20 cm -3 ), in line with theoretical prediction. This work not only propose...