Fabrication of large-scale single-crystal bismuth telluride (Bi₂Te₃) nanosheet arrays by a single-step electrolysis process.
Nanolizing of thermoelectric materials is one approach to reduce the thermal conductivity and hence enhance the figure of merit. Bismuth telluride (Bi₂Te₃)-based materials have excellent figure of merit at room temperature. For device applications, precise control and rapid fabrication for the nanostructure of thermoelectric materials are essential issues. In the present study, we demonstrate a one-step electrolysis process to directly form Bi₂Te₃ nanosheet arrays (NSAs) on the surface of bulk Bi₂Te₃ with controllable spacing distance and depth by tuning the applied bias and duration. The single sheet of NSAs reveals that the average thickness and electrical resistivity of single crystalline Bi₂Te₃ in composition are 399.8 nm and 137.34 μΩ m, respectively. The formation mechanism of NSAs has been proposed. A 1.12% efficiency of quantum dot-sensitized solar cells with Bi₂Te₃ NSAs for counter electrode has been demonstrated, indicating that Bi₂Te₃ NSAs from top-down processing with a high ratio of surface area to volume are a promising candidate for possible applications such as thermoelectrics, dye-sensitized solar cells (DSSCs), and lithium-ion batteries.
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan.
Hung-Wei
HW
Tsai
Tsang-Hsiu
TH
Wang
Tsung-Cheng
TC
Chan
Pei-Ju
PJ
Chen
Chih-Chun
CC
Chung
Alireza
A
Yaghoubi
Chien-Neng
CN
Liao
Eric Wei-Guang
EW
Diau
Yu-Lun
YL
Chueh