Abstract:Bismuth tellurides is one of the most promising thermoelectric (TE) material candidates in low-temperature application circumstances, but the n-type thermoelectric property is relatively low compared to the p-type counterpart and still needs to be improved. Herein, we incorporated different copper selenides (CuSe, Cu3Se2 and Cu2−xSe) into a Bi2Te3 matrix to create the alloy by grinding and successive sintering to enable higher thermoelectric performance. The results demonstrated that all alloys achieved n-type… Show more
“…9d ) 35 – 44 . It is worth to note that the reported high performance outperforms other well-known n -type thermoelectric systems as well 45 – 51 .…”
Section: Resultsmentioning
confidence: 76%
“…Consequently, we successfully achieved a record-high ZT value of 2.2 in n -type polycrystalline SnSe 0.92 + 0.03WCl 6 , which outperforms the most state-of-the-art n -type thermoelectric systems (Fig. 1b ), highlighting the prospect of advancing thermoelectrics 45 – 51 . Fig.…”
N-type polycrystalline SnSe is considered as a highly promising candidates for thermoelectric applications due to facile processing, machinability, and scalability. However, existing efforts do not enable a peak ZT value exceeding 2.0 in n-type polycrystalline SnSe. Here, we realized a significant ZT enhancement by leveraging the synergistic effects of divacancy defect and introducing resonance level into the conduction band. The resonance level and increased density of states resulting from tungsten boost the Seebeck coefficient. The combination of the enhanced electrical conductivity (achieved by increasing carrier concentration through WCl6 doping and Se vacancies) and large Seebeck coefficient lead to a high power factor. Microstructural analyses reveal that the co-existence of divacancy defects (Se vacancies and Sn vacancies) and endotaxial W- and Cl-rich nanoprecipitates scatter phonons effectively, resulting in ultralow lattice conductivity. Ultimately, a record-high peak ZT of 2.2 at 773 K is achieved in n-type SnSe0.92 + 0.03WCl6.
“…9d ) 35 – 44 . It is worth to note that the reported high performance outperforms other well-known n -type thermoelectric systems as well 45 – 51 .…”
Section: Resultsmentioning
confidence: 76%
“…Consequently, we successfully achieved a record-high ZT value of 2.2 in n -type polycrystalline SnSe 0.92 + 0.03WCl 6 , which outperforms the most state-of-the-art n -type thermoelectric systems (Fig. 1b ), highlighting the prospect of advancing thermoelectrics 45 – 51 . Fig.…”
N-type polycrystalline SnSe is considered as a highly promising candidates for thermoelectric applications due to facile processing, machinability, and scalability. However, existing efforts do not enable a peak ZT value exceeding 2.0 in n-type polycrystalline SnSe. Here, we realized a significant ZT enhancement by leveraging the synergistic effects of divacancy defect and introducing resonance level into the conduction band. The resonance level and increased density of states resulting from tungsten boost the Seebeck coefficient. The combination of the enhanced electrical conductivity (achieved by increasing carrier concentration through WCl6 doping and Se vacancies) and large Seebeck coefficient lead to a high power factor. Microstructural analyses reveal that the co-existence of divacancy defects (Se vacancies and Sn vacancies) and endotaxial W- and Cl-rich nanoprecipitates scatter phonons effectively, resulting in ultralow lattice conductivity. Ultimately, a record-high peak ZT of 2.2 at 773 K is achieved in n-type SnSe0.92 + 0.03WCl6.
“…Besides, we achieved a high ZT of 0.56 at 369 K, which is significantly improved by ∼167% compared with that of the bulk material sintered from commercial Bi 2 Te 3 powders, indicating great potential for practical applications. Compared with the reported pristine polycrystalline Bi 2 Te 3 fabricated by different methods (Table S1 in the Supporting Information), − our as-achieved ZT value is relatively competitive.…”
Bi2Te3 is one of the most promising
thermoelectric
materials that target near-room-temperature applications due to its
high thermoelectric potential at these temperatures. In this work,
we report a new route to significantly improve the thermoelectric
performance of pristine Bi2Te3 polycrystals.
We design the mixed solutions composed of H2O and ethylene
glycol (EG) as novel solvents to solvothermally synthesize Bi2Te3 crystalline microplates. It is found that the
addition of H2O can boost the saturated vapor pressure
of the mixed solutions during the solvothermal synthesis and significantly
drive the crystal growth of Bi2Te3 microplates
along their in-plane directions due to the tuning of kinetic conditions.
Such a unique route strengthens the anisotropy of the bulk materials
sintered from these microplates, leading to improved carrier mobility
of >170 cm2 V–1 s–1 and in turn a high electrical conductivity of >1400 S cm–1 at room temperature. Combined with a high absolute
Seebeck coefficient
of >140 μV K–1, a competitively high power
factor of ∼30 μW cm–1 K–2 can be achieved in the solvothermally synthesized samples. Besides,
compared with the bulk material sintered from commercial Bi2Te3 powders with a figure of merit of 0.2 at 369 K, the
figure of merit of the bulk material developed in this work is significantly
improved by ∼167% (0.56), indicating great potential for practical
applications. This work paves a new way and fills the gap of boosting
the thermoelectric performance of pristine Bi2Te3.
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