Lee, Seunghyeok Jung, Sung-Jin Park, Gwang Min Hong, Junpyo Lee, Albert S. Baek, Seung-Hyub Kim, Heesuk Park, Tae Joo Kim, Jin-Sang Kim, Seong Keun 2024-01-19T09:05:24Z 2024-01-19T09:05:24Z 2023-04-13 2023-07 0955-2219 https://pubs.kist.re.kr/handle/201004/113568 This study demonstrates atomic layer deposition (ALD) of an extremely thin Al2O3 layer over n-type Bi2Te2.7Se0.3 to alleviate the adverse effects of multiple boundaries on their thermoelectric performance. Multiple boundaries reduce thermal conductivity (kappa), but generate electrons, deviating from the optimum carrier concentration. Only one Al2O3 ALD cycle effectively suppresses Te volatilization at the grain boundaries, resulting in a decrease from 5.8 x 10(19)/cm(3) to 3.6 x 10(19)/cm(3) in the electron concentration. Concurrently, the one-cycle-Al2O3 coating produces fine grains, thus inducing numerous boundaries, ultimately suppressing the lattice kappa from 0.64 to 0.33 W/m center dot K. A further increase in the number of Al2O3 cycles leads in a significant rise in the resistance, resulting in degradation of thermoelectric performance. Consequently, the ZT value is increased by 51 % as a result of Al2O3 coating with a single ALD cycle. Our approach offers new insights into the simultaneous reduction of the kappa and electron concentration in n-type Bi2Te3-based materials. English Elsevier BV Grain boundary engineering strategy for simultaneously reducing the electron concentration and lattice thermal conductivity in n-type Bi2Te2.7Se0.3-based thermoelectric materials Article 10.1016/j.jeurceramsoc.2023.02.017 1 Journal of the European Ceramic Society, v.43, no.8, pp.3376 - 3382 Journal of the European Ceramic Society 43 8 3376 3382 Y scie scopus 000955279300001 2-s2.0-85148713203 Materials Science, Ceramics Materials Science Article HIGH-PERFORMANCE BI2TE3 FIGURE NANOCOMPOSITES BISMUTH ZT Thermoelectric materials Grain boundary engineering Carrier concentration Atomic layer deposition N-type Bi2Te2.7Se0.3 (BTS)