Significantly enhanced thermoelectric performance of Cu-doped p-type Bi_0.5Sb_1.5Te₃ by a hydrothermal synthesis method

Abstract

Cu-doped p-type Bi 0.5 Sb 1.5 Te 3 compounds have been prepared by a facile hydrothermal method. X-ray powder diffraction analysis shows that the lattice parameter decreases with the Cu content, indicating that Cu + ions are distributed on the crystal site of Bi/Sb, which is further confirmed by the p-type conducting behavior of the Cu-doped Bi 0.5 Sb 1.5 Te 3 . With the addition of Cu, the hole carrier concentration increases, and meanwhile the lattice thermal conductivity decreases. Furthermore, the greatly raised hole carrier concentration effectively suppresses the bipolar effect, which is beneficial for improving the thermoelectric properties. A dimensionless thermoelectric figure of merit (ZT) value of $1.2 at room temperature is achieved for the sample with 0.6 wt% Cu (nominal composition), and the ZT value increases with the temperature to $1.5 at 150 C. Cu-doped Bi 0.5 Sb 1.5 Te 3 samples exhibit most excellent thermoelectric performance among the presently available (Bi,Sb) 2 Te 3 -based materials, implying great potential as near room temperature thermoelectric materials.

Synergistically Optimized Thermoelectric Performance in Bi0.48Sb1.52Te3 by Hot Deformation and Cu Doping

“…Among a few known effective dopants, Cu has attracted continuous research interests. − However, the role of the Cu dopant in the electron/thermal transports of Bi 2 Te 3 -based alloys has not been completely clarified. Some research suggest that the copper atom intercalates into the van der Waals space and works as an electrical connection between the quintuple layers, leading to the improvement of carrier mobility. ,, Some others suggest that the copper atom substitutes the Bi or Sb site and introduces an additional hole, resulting in the increase of hole concentration. , …”

Enhanced room-temperature thermoelectric performance of p-type BiSbTe by reducing carrier concentration

“…Atomic doping in p-type Bi 0.5 Sb 1.5 Te 3 is generally performed to increase the carrier concentration, [22][23][24][25][26] thereby improving the electrical conductivity to achieve enhanced thermoelectric properties. For instance, the substitution of Ag + , 22,23,26 Cu + (ref.…”

“…For instance, the substitution of Ag + , 22,23,26 Cu + (ref. 24) and Cd 2+ (ref. 25) for Bi 3+ /Sb 3+ results in an increased hole concentration which suppresses the bipolar effect, leading to improved thermoelectric properties at high temperature.…”

Enhancing Thermoelectric and Mechanical Properties of p-Type (Bi, Sb)2Te3 through Rickardite Mineral (Cu2.9Te2) Incorporation

“…46 Moreover, doping (Bi, Sb) 2 Te 3 with Ag, Pb, Cu, or Cd increased the hole concentration, thereby hindering the bipolar effect, but at the expense of reduced carrier mobility. 25,[39][40][41][42]47 Among these elements, several studies were focused on Cu through direct doping or by adding a binary Cu-rich alloy.…”