Semiconductor glass with superior flexibility and high room temperature thermoelectric performance

Abstract

Most crystalline inorganic materials, except for metals and some layer materials, exhibit bad flexibility because of strong ionic or covalent bonds, while amorphous materials usually display poor electrical properties due to structural disorders. Here, we report the simultaneous realization of extraordinary room temperature flexibility and thermoelectric performance in Ag2Te1–xSx–based materials through amorphization. The coexistence of amorphous main phase and crystallites results in exceptional flexibility and ultralow lattice thermal conductivity. Furthermore, the flexible Ag2Te0.6S0.4 glass exhibits a degenerate semiconductor behavior with a room temperature Hall mobility of ~750 cm2 V−1 s−1 at a carrier concentration of 8.6 × 1018 cm−3, which is at least an order of magnitude higher than other amorphous materials, leading to a thermoelectric power factor also an order of magnitude higher than the best amorphous thermoelectric materials known. The in-plane prototype uni-leg thermoelectric generator made from this material demonstrates its potential for flexible thermoelectric device.

Ductile Ag20S7Te3 with Excellent Shape‐Conformability and High Thermoelectric Performance

“…However, this approach needs the TE materials possessing both high ductility and excellent TE dimensionless figure of merit ( zT = S 2 σT /κ, where S is Seebeck coefficient, σ is electrical conductivity, κ is thermal conductivity, and T is the absolute temperature), which are very rare in known materials. [ 24,25 ]…”

“…It should be noted that the X‐ray diffraction pattern of Ag 20 S 7 Te 3 is also different from that of Ag 2 Te 0.6 S 0.4 , which is reported to be an amorphous material, with no visible diffraction peaks in the X‐ray diffraction pattern. [ 25 ]…”

“…Actually, this zT value is already comparable with that of the n‐type commercial brittle Bi 2 Te 3 ‐based alloys (see the dashed line in Figure 3f. [ 25 ]…”

Crystalline Structure-Dependent Mechanical and Thermoelectric Performance in Ag2Se1‐xSx System

“…Alloying Se or/and Te in Ag 2 S can significantly improve σ and enhance zT to 0.26 for Ag 2 S 0.5 Se 0.5 and 0.44 for Ag 2 S 0.5 Se 0.45 Te 0.05 at 300 K. Particularly, previous study showed that the good ductility can be well maintained when the Se alloying content in Ag 2 S reaches 50% or the Te alloying content reaches 20%, enabling these materials very suitable to be used in flexible wearable electronics. The above results arouse great interest on the Ag 2 S-based materials in TE society [ 21 , 23 – 25 ].…”

A flexible micro-thermoelectric device from carbon nanotube-epitaxially grown (Bi,Sb)2Te3 nanocrystal

“…First, traditional inorganic TE materials are intrinsically rigid, and are largely restricted to building planar TEDs, which yield a low TE performance owing to the poor thermal contacts between the TED and curved heat source or sink. As a result, there have been tremendous efforts in recent years to develop flexible TE materials [11][12][13][14][15][16][17][18][19][20][21][22][23] . Nevertheless, limited by the degraded property of flexible TE materials and integration technology, the performance of current flexible TEDs [13][14][15]19,[24][25][26][27][28][29][30][31] is usually far worse than that of conventional ones.…”