Enhanced thermoelectric properties of n-type Bi2Te2.7Se0.3 materials by TiO2 ceramic nanoparticle dispersion-induced energy filtering effect

Due to their superior thermoelectric capabilities, Bi2Te3-based materials have long been a popular area of study in the thermoelectric field. However, further advancements in the energy conversion efficiency of Bi2Te3-based thermoelectric modules are constrained by the low figure of merit of n-type Bi2Te3. Here, we describe an efficient method for enhancing the electrical and thermal characteristics of n-type Bi2Te2.7Se0.3 (BTS) material by dispersing TiO2 ceramic nanoparticles (NPs) in the matrix of the BTS. In more detail, the energy potential barrier, created by the matrix and the addition of TiO2 NPs, causes an energy filtering effect, which in turn raises the Seebeck coefficient. The lattice thermal conductivity is decreased as a result of dislocations at the TiO2/BTS interface and an increase in grain boundary density brought on by the fine grain strengthening of TiO2 ceramic NPs. Last but not least, the ZTmax for the BTS + 3 wt% TiO2 sample increased to 1.31, representing an improvement of 52% over the pristine sample. Additionally, at a maximum temperature differential of 150K, we have built a thermoelectric module with a power output and energy conversion efficiency of 7.2 W and 5.9%, respectively. This study introduces a viable approach towards the rational design of advanced n-type Bi2Te2.7Se0.3 materials.