High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

Abstract

Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm2 with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

“…This section mainly reviews the strategies for developing continuous inorganic FTE thin films, which includes inorganic films grown on flexible substrates and free‐standing inorganic FTE thin films. Although vacuum‐assisted filtration methods or screen‐printing has been used to realize the material flexibility of deposited inorganic thin films, as‐fabricated inorganic films are composed of noncontinuous nanoparticles, and the flexibility is entirely from the substrate. Therefore, these approaches are not highlighted in this section.…”

Recent Progress in Biomimetic Additive Manufacturing Technology: From Materials to Functional Structures

“…Experimental and calculated open circuit voltage versus temperature differences (right). Reproduced with permission . Copyright 2016, Nature Publishing Group.…”

Energy harvesting using thermoelectricity for IoT (Internet of Things) and E-skin sensors

“…Conventional thermoelectric modules are in rigid forms with ceramic plates on top and bottom sides which limit their application to flat surfaces. To overcome such limitation, thermoelectric devices based on a flexible substrate using a printing method [56][57][58][59][60][61][62] or structural design with inorganic bulk thermoelectric materials [25,26,47,63] have been researched. Thermoelectric materials used near room temperature are mainly Bi-Te based compounds, Bi 2-x Sb x Te 3 for p-type and Bi 2 Te 3-x Se x for n-type, due to its high thermoelectric performance [64,65].…”

“…Materials for both printing and inorganic bulk thermoelectric materials are based on Bi-Te compounds. For the material for printing, Bi-Te powders mixed with solvents are adopted for the manufacturing [58,61]. Inorganic bulk thermoelectric materials used near room temperature are normally Bi-Te compounds in polycrystalline structure.…”