High Thermoelectric zT in n‐Type Silver Selenide films at Room Temperature

Abstract

In this work, a zT value as high as 1.2 at room temperature for n‐type Ag2Se films is reported grown by pulsed hybrid reactive magnetron sputtering (PHRMS). PHRMS is a novel technique developed in the lab that allows to grow film of selenides with different compositions in a few minutes with great quality. The improved zT value reported for room temperature results from the combination of the high power factors, similar to the best values reported for bulk Ag2Se (2440 ± 192 µW m−1 K−2), along with a reduced thermoelectric conductivity as low as 0.64 ± 0.1 W m−1 K−1. The maximum power factor for these films is of 4655 ± 407 µW m−1 K−2 at 103 °C. This material shows promise to work for room temperature applications. Obtaining high zT or, in other words, high power factor and low thermal conductivity values close to room temperature for thin films is of high importance to develop a new generation of wearable devices based on thermoelectric heat recovery.

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

“…Such a fabrication mechanism is similar to LbL deposition . Taking the Ag 2 Se thin film as an example, by controlling the operation time of pulsed heating valves, a certain amount of Ag can be controlled to deposit on the substrate, then a proper amount of Se is released to react directly with the deposited Ag film . Such a fabricated Ag 2 Se thin film has a high stoichiometry with a promising high S 2 σ of 46.55 µW cm −1 K −2 at 376 K .…”

“…[366] Taking the Ag 2 Se thin film as an example, by controlling the operation time of pulsed heating valves, a certain amount of Ag can be controlled to deposit on the substrate, then a proper amount of Se is released to react directly with the deposited Ag film. [367] Such a fabricated Ag 2 Se thin film has a high stoichiometry with a promising high S 2 σ of 46.55 µW cm −1 K −2 at 376 K. [367] Although such a Ag 2 Se thin film has been fabricated on a glass substrate, this configuration did not address the flexibility issue. Despite this, the superhigh TE performance and the facile methodology hold great potential for the development of high-performance inorganic FTE thin films in the future.…”

Promising and Eco‐Friendly Cu2X‐Based Thermoelectric Materials: Progress and Applications

“…In more recent years, strongly anisotropic SnSe and BiCuSeO have been evidenced possessing high electrical performance as well as low κ l and subsequently high zT due to layered structure . With liquid‐like behavior, superionic materials, such as Cu 2 X‐based (X = Te, Se, and S) thermoelectric materials, Ag 2 Se, and Ag 2 S, are also experiencing high zT with ultralow κ l .…”

“…[83][84][85][86] In more recent years, strongly anisotropic SnSe [26,45,47,[87][88][89][90][91][92] and BiCuSeO [1,[93][94][95][96] have been www.advmat.de www.advancedsciencenews.com evidenced possessing high electrical performance as well as low κ l and subsequently high zT due to layered structure. [34,35,40,44] With liquid-like behavior, [72,[97][98][99] superionic materials, such as Cu 2 X-based (X = Te, Se, and S) thermoelectric materials, [72,99,100] Ag 2 Se, [97,101] and Ag 2 S, [6] are also experiencing high zT with ultralow κ l . Figure 1a shows the peak zT values of various state-of-the-art p-type thermoelectric materials at different temperatures.…”

Anisotropy Control–Induced Unique Anisotropic Thermoelectric Performance in the n‐Type Bi2Te2.7Se0.3 Thin Films

“…[8,22] For example, with high flexibility, thin thermoelectric films can conveniently attach on human skin, which shows great potentials to utilize the temperature gradient between human body and surrounding environment to generate electricity to charge cell phones. [8,10,23] Limited by the low S value (<100 µV K −1 ) for organic flexible thermoelectrics, [22,24,25] inorganic films with high electrical performance are exhibiting ever-growing interest, including Ag 2 S-, [26] Ag 2 Se-, [27] TiS 2 -, [28] and Bi 2 Te 3based materials. [29][30][31] Bi 2 Te 3 -based thermoelectric materials are the widely studied due to their excellent low-temperature zT values derived from layered crystal structure and anisotropic thermoelectric properties.…”