We compare the optimized TE performances of p-type and ntype Y 2 Te 3 by assessing the material quality factor β , which is given by where µ 0 is the intrinsic carrier mobility, m * DOS is the densityof-states effective mass, and κ L is the lattice thermal conductivity. We calculate µ 0 and κ L at 300 K using parameterized semiempirical models, where the model inputs are obtained from density functional theory (DFT) calculations. The details of these models and methods to calculate the input parameters are documented in Refs. 35 and 36. We estimate the room-temperature κ L in single crystals to be 2.96 W/mK, which is higher than the experimentally measured value of 1.9 W/mK (at 300 K) 10 in polycrystalline samples where grain boundary scattering lowers κ L . We also estimate the room-temperature electron and hole mobilities to be 62 and 20 cm 2 /Vs, respectively (Table ). The mobility computed with the semi-empirical model provides an estimate of the intrinsic phonon scattering-limited mobility and therefore should be treated as an upper limit. Additional sources of scattering such as ionized impurities in heavily-doped semiconductors will reduce the carrier mobility. Larger β values signify higher optimized TE performance. We find that Y 2 Te 3 has a larger n-type β of 1.2 (relative to PbTe) compared to p-type (Table ). The larger Maximum zT > 0.8 is obtained in 900-1200 K when the electron concentration is optimized to 1 -2 × 10 20 cm -3 .