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The temperature dependence of the Hall mobility, Seebeck coefficient, electrical resistivity, thermal conductivity, and figure-of-merit of the SbI3 and CuBr-doped 85% Bi2Te3-15% Bi2Se3 single crystals have been characterized at temperatures ranging from 77 K to 600 K. The scattering parameter in 85% Bi2Te3-15% Bi2Se3 single crystal was determined as 0.1 from the temperature dependence of the carrier mobility. With increasing the amount of Sbl3 or CuBr doping, the Seebeck coefficient of 85% Bi2Te3-15% Bi2Se3 decreased and the temperature at which the Seebeck coefficient shows a maximum shifted to higher temperature. Compared to the Sbl3-doped specimens, the CuBr-doped single crystals exhibited higher (m* / m0)3/2 μc, implying that CuBr is a more effective dopant to improve the material factor and thus the figure-of-merit of 85% Bi2Te3-15% Bi2Se3. The maximum figure-of-merit of 2.0 × 10−3/K and 2.2 × 10−3/K was obtained for 0.1 wt % Sbl3-doped specimen and 0.03 wt % CuBr-doped specimen, respectively.