From Brittle to Ductile: A Scalable and Tailorable All-Inorganic Semiconductor Foil through a Rolling Process toward Flexible Thermoelectric Modules

Abstract

Inorganic thermoelectric (TE) materials with outstanding capacity for energy conversion are expected to be promising eco-friendly and renewable power sources, but they are always intrinsically brittle, restricting their development in flexible TE electronics. Therefore, we have developed a facile manufacturing method of large-scale all-inorganic silver chalcogenide foils and flexible TE generators in this work. A rolling process, as an effective and facile molding technique, is applied in ductile TE materials. The figure-of-merit for flexibility of this free-standing foil is in the range of 0.02−0.13, suggesting the superior flexibility of the allinorganic TE foils. A high TE figure-of-merit ZT of 0.47 at room temperature is reached for Ag 2 S 0.45 Se 0.45 Te 0.1 , which is one of the most promising room-temperature ZTs among flexible TE materials. A proof-of-concept flexible TE generator based on silver chalcogenide foils achieves an open-circuit voltage of 1.19 mV and an output power density of 1.8 mW/m 2 with a temperature difference of 2.7 °C across the TE leg, showing great potential in heat-to-electricity conversion.

Optimized Thermoelectric Performance and Plasticity of Ductile Semiconductor Ag2S0.5Se0.5 Via Dual‐Phase Engineering

“…[ 53 ] Besides, Se/Te co‐alloying can realize higher ZT values at room temperature. Ag 2 S 0.5 Se 0.45 Te 0.05 and Ag 2 S 0.45 Se 0.45 Te 0.1 alloys exhibited high ZT values of ≈0.44 and 0.47 at 300 K, [ 37,54 ] respectively. Such high room temperature thermoelectric performance originated from the ultra‐low κ l .…”

Robust, Flexible Thermoelectric Film for Energy Harvesting by a Simple and Eco-Friendly Method

“…5 To date, there are three main categories of approaches to address the flexibility of the TE materials. The first category of approaches is searching for flexible, high-performance inorganic materials, 6 such as Ag 2 S. 7 However, most of them are scarce. The second category of approaches is searching organics which have flexibility and high TE performance.…”

Flexible Ag–S–Te System with Promising Room-Temperature Thermoelectric Performance

“…Subsequently, the flexibility of single-crystal ZnS in the complete darkness and single-crystal InSe is revealed. The relatively large bandgap (∼1 eV) of Ag 2 S gives electrical conductivity on the order of 10 –1 S m –1 , resulting in poor TE performance. , Alloying a certain amount of Se − or Cu , to Ag 2 S is an effective way to improve its TE performance at ambient temperature, and the discovery of amorphous Ag 2 S 0.4 Te 0.6 provides another new idea for optimizing the deformability and TE performance of ductile inorganic semiconductor. − …”