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With the development of application of wireless sensor nodes (WSNs), the need for energy harvesting is rapidly increasing. In this study, we designed and fabricated a robust monolithic thermoelectric generator (TEG) using a simple, low-energy, and low-cost device fabrication process. Our monolithic device consists of Ag

Wearable thermoelectric generators (w-TEGs) can incessantly convert body heat into electricity to power electronics. However, the low efficiency of thermoelectric materials, tiny terminal temperature difference, rigidity, and negligence of lateral heat transfer preclude broad utilization of w-TEGs. In this work, we employ finite element simulation to find the key factors for simultaneous realization of flexibility and ultrahigh normalized power density. Using melamine foam with an ultralow thermal conductivity (0.03 W/m K) as the encapsulation material, a novel lightweight π-type w-TEG with no heatsink and excellent stretchability, comfortability, processability, and cost efficiency has been fabricated. At an ambient temperature of 24 °C, the maximum power density of the w-TEG reached 7 μW/cm

In this study, a micro in-plane p-type thermoelectric generator (TEG), which consists of thin-film Si1−x−yGexSny ternary alloy semiconductor on insulator, is developed to make efficient use of waste heat such as human body. A power factor value as high as 1095 μWm−1K−2 had been achieved using B-ion implanted and short-term rapid thermal annealing (RTA) process. In addition, a measuring scheme for micro TEG without external load resistance was designed. In one measuring session, multiple parameters can be measured. The micro single-arm TEG prepared by semiconductor process can output 0.29 nW power at a temperature difference of 15 K, and a cross-sectional power density has reached up to 0.58 mW/cm2, which is a superior value for wearable device. The findings of this study have important reference value for wearable device performance improvement and output power measuring of micro TEG.

Generation of electricity from waste heat using thermoelectric devices is one of the best ways to produce the clean energy. Number of applications would become enormous when such devices possess good mechanical strength and high performance in ambient conditions. Here, we design and fabricated such a robust thermoelectric generator (TEGs) using chalcogenide materials in the short time and easy-implemented hot pressing in air. Our typical monolithic π -type device consists of Ag 2 S 0.2 Se 0.8 and Bi 0.5 Sb 1.5 Te 3 for n -type and p -type legs, respectively. The empty space between the legs were filled with highly dense and flexible, thin Ag 2 S working both as insulating spacer and shock absorber, which makes the device very robust and prevents it from any damage due to external mechanical force. The dimension of TEGs device, which is made up with 3 pairs of p - n legs, is 12 mm × 10 mm × 10 mm. From the simulation using COMSOL software, the maximum power density of the device at temperature difference of 50 K were found to be 2.1 and 8.2 mWcm –2 with and without the consideration of the contact resistance at the p - n junction, respectively. Using the novel measurement technique independent of load resistance, the measured maximum power density of the fabricated device was successfully achieved to 2.02 mWcm –2 at room temperature, which confirms the accuracy and wide trial of our measurement technology in obtaining the robust TEG for wide applications.

As the first-generation semiconductor, silicon (Si) exhibits promising prospects in thermoelectric (TE) convention application with the advantages of un-toxic, abundant, robust, and compliant to the integrated circuit. However, Si-based TE materials are always implemented for high-temperature application and deficient at room temperature (RT) ambience. This study displays an N-type Si1−x−yGexSny thin film by carrying out the strategy of metallic modulation doping for enhancing its power factor (PF). It was distinct to observe the extra carriers poured from the precipitated Sn particles without prominent degradation of mobility while sustaining appreciable thermal conductivity. The PF of 12.21 μW cm−1 K−2 and zT of 0.27 were achieved at 125 °C, which illustrated the significant potential for implementation at near RT ambiance.

In this study, we report a power factor (PF) value as high as 1950 μW m−1 K−2 for B-ion implanted thermoelectric Si1-x-yGexSny ternary alloy films at ambient temperature by radio frequency sputtering followed by a short-term rapid thermal annealing heat treatment. The record high PF value was realized by modulation doping of Sn in the Si1-x-yGexSny film. It was found that using metallic Sn as nanoparticles and Si1-x-yGexSny as the matrix leads to a large enhancement of the carrier concentration and a very small decrease in carrier mobility. As a result, the electrical conductivity and power factor of the modulation doped Si1-x-yGexSny alloy were greatly improved. The findings of this study present emerging opportunities for the modulation of Si integration thermoelectrics as wearable devices charged by body temperature.

Summary Silver selenide is considered as a promising room temperature thermoelectric material due to its excellent performance and high abundance. However, the silver selenide-based flexible film is still behind in thermoelectric performance compared with its bulk counterpart. In this work, the composition of paper-supported silver selenide film was successfully modulated through changing reactant ratio and annealing treatment. In consequence, the power factor value of 2450.9 ± 364.4 μW/(mK2) at 303 K, which is close to that of state-of-the-art bulk Ag2Se has been achieved. Moreover, a thermoelectric device was fabricated after optimizing the length of annealed silver selenide film via numerical simulation. At temperature difference of 25 K, the maximum power density of this device reaches 5.80 W/m2, which is superior to that of previous film thermoelectric devices. Theoretically and experimentally, this work provides an effective way to achieve silver-selenide-based flexible thermoelectric film and device with high performance., Graphical Abstract, Highlights • A remarkably improved power factor is achieved by annealing treatment • Optimal length of Ag-rich Ag2Se film is obtained via a numerical simulation • A high output power density at temperature difference of 25 K is realized, Electrochemical Materials Science; Materials Synthesis; Energy Materials