Remarkable Enhancement in Thermoelectric Performance of BiCuSeO by Cu Deficiencies

Abstract

A significant enhancement of thermoelectric performance in layered oxyselenides BiCuSeO was achieved. The electrical conductivity and Seebeck coefficient of BiCu(1-x)SeO (x = 0-0.1) indicate that the carriers were introduced in the (Cu(2)Se(2))(2-) layer by Cu deficiencies. The maximum of electrical conductivity is 3 × 10(3) S m(-1) for Bicu(0.975)Seo at 650 °C, much larger than 470 S m(-1) for pristine BiCuSeO. Featured with very low thermal conductivity (∼0.5 W m(-1) K(-1)) and a large Seebeck coefficient (+273 μV K(-1)), ZT at 650 °C is significantly increased from 0.50 for pristine BiCuSeO to 0.81 for BiCu(0.975)SeO by introducing Cu deficiencies, which makes it a promising candidate for medium temperature thermoelectric applications.

Promising Thermoelectric Bulk Materials with 2D Structures

“…[80] According to solid state physical principles, the ZT value for bulk mate rials with a single parabolic band (SPB) along a certain direc tion can be given as: [4] The timeline for thermoelectric bulk materials with 2D structures, showing data from a superlattice, [8] SnSe, [11,[19][20][21] Bi 2 Te 3 , [12,14,16,17,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] BiCuSeO, [12,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Na x CoO 2 , [57,58] Ca 3 Co 4 O 9 , [5...…”

Enhanced thermoelectric performance through grain boundary engineering in quaternary chalcogenide Cu2ZnSnSe4

“…1 Many strategies have been employed to enhance the power factor and suppress the thermal conductivity. For instance, the power factor of thermoelectric materials can be enhanced via the convergence of electronic bands, 2 optimization of the carrier concentrations, 3,4 as well as the introduction of resonant impurity energy bands inside the conduction or valence band. 5,6 On the other hand, structural manipulations have been adopted to suppress the thermal conductivity, such as introducing nanoscale structures to reduce the phonon mean free path, point defect scattering through alloying with other elements, and lone pair electron to develop soft phonon modes.…”

Understanding the electronic and phonon transport properties of a thermoelectric material BiCuSeO: a first-principles study

“…An effective way of searching good TE materials is to find materials with intrinsic low lattice thermal conductivity, such as CoSb 3 [1], AgSbTe 2 [2], and MgAgSb [3]. Recently, a new layered oxyselenide BiCuSeO with very small lattice thermal conductivity was proposed to be a potential TE material [4], and a large amount of efforts have been devoted to enhance its TE performance [5][6][7][8][9]. Over the past five years, the ZT value of BiCuSeO has been continuously increased from 0.76 to 1.5 by doping to enhance the power factor as well as nanostructuring to further reduce the lattice thermal conductivity.…”