Microstructurally Tailored Thin β‐Ag₂Se Films toward Commercial Flexible Thermoelectrics

Abstract

Aiming to overcome both the structural and commercial limitations of flexible thermoelectric power generators, an efficient room‐temperature aqueous selenization reaction that can be completed in air within less than 1 min, to directly fabricate thin β‐Ag2Se films consisting of perfectly crystalline and large columnar grains with both in‐plane randomness and out‐of‐plane [201] preferred orientation, is designed. A high power factor (PF) of 2590 ± 414 µW m−1 K−2 and a figure‐of‐merit (zT) of 1.2 ± 0.42 are obtained from a sample with a thickness of ≈1 µm. The maximum output power density of the best 4‐leg thermoelectric generator sample reach 27.6 ± 1.95 and 124 ± 8.78 W m−2 at room temperature with 30 and 60 K temperature differences, respectively, which may be useful in future flexible thermoelectric devices.

Ag2Se/nylon self-supporting composite films for wearable photo-thermoelectric generators with high output characteristics

“…Meanwhile, it can be noted that the thicknesses of the composite films are generally distributed above 60 μm, which are several times higher compared to the thicknesses of the non-self-supporting films. 18 The optimized thicknesses will not affect their output voltages but will lead to significant increases in their output current, which in turn will have a favorable impact on the subsequent output powers.…”

“…The crystal planes in the (010) direction have been reported to have a higher TE property compared to the other two planes, so the gradual expansion of the orientation of (201) may also play a role in the improvement of the performance of the final composite films. 18 EDS analysis (Fig. S12†) and the XPS wide spectrum (Fig.…”

“…4a), and the extremely narrow band gap makes it easy for the electrons to leap back down to generate heat under the action of incident light. 18 At the same time, its low thermal conductivity makes it difficult for heat to dissipate and thus better PT performances are exhibited.…”

“…Although various bismuth and tellurium compounds have been rapidly developed to satisfy the high ZT demand in the past few decades, and some of them have even become common commercial products, 18 their further development is severely limited by toxicity and scarcity, so it is crucial to explore and develop alternatives with low toxicity, high TE properties and earth abundance. As an n-type narrow bandgap semiconductor, Ag 2 Se has the advantages of low toxicity, high carrier mobility and low κ l , which is a typical “phonon-glass electron-crystal” material, 16 and it is also considered to be a strong contender for room-temperature (RT) TE materials.…”

A facile route to fabricating a crack-free Mg0.99Cu0.01Ag0.97Sb0.99/graphene/PEDOT:PSS thermoelectric film on a flexible substrate

“…Therefore, it is highly essential to develop FTE devices, which are Te free and contain less toxic elements. Recently, through novel fabrication technologies and rational structure design, n-type Ag 2 Se-based films with high thermoelectric properties targeting commercialization have been demonstrated, [33][34][35] which invokes the motivation to improve the performance of the existing TE materials by different optimizing technologies.…”