Solution processed organic thermoelectric generators as energy harvesters for the Internet of Things

Abstract

Organic thermoelectric generators (TEGs) are a prospective class of versatile energy-harvesters that can enable the capture of low-grade heat and provide power to the growing number of microelectronic devices and sensors in the Internet of Things. The abundance, low-toxicity, and tunability of organic conducting materials along with the scalability of the fabrication techniques promise to culminate in a safe, low-cost, and adaptable device template for a wide range of applications. Despite recent breakthroughs, it is generally recognized that significant advances in n-type organic thermoelectric materials must be made before organic TEGs can make a real impact. Yet, in this perspective, we make the argument that to accelerate progress in the field of organic TEGs, future research should focus more effort into the design and fabrication of application-oriented devices, even though materials have considerable room for improvement. We provide an overview of the best solution-processable organic thermoelectric materials, design considerations, and fabrication techniques relevant for application-oriented TEGs, followed by our perspective on the insight that can be gained by pushing forward with device-level research despite suboptimal materials.

Enhanced Electrical Conductivity and Mechanical Properties of Stretchable Thermoelectric Generators Formed by Doped Semiconducting Polymer/Elastomer Blends

“…Additionally, the generated electricity can be used to operate TE devices, such as solid-state heat pumps for distributed refrigeration. The recent surge in the market for wearable electronics and the advent of internet of things (IoT) technology have spurred a pronounced interest in TEGs due to their potential use as long-lasting, portable, and maintenance-free power sources . These devices hold immense promise in leveraging the temperature differential between the human body and the environment as a heat source for powering low-power wearable electronics and realizing self-powered systems.…”

The role of substrates and electrodes in inkjet-printed PEDOT:PSS thermoelectric generators

“…Moreover, inkjet printing is a digital technique that is particularly suitable for rapid prototyping as it does not require a physical mask to define a specific layout because the layout to be printed is designed by software and can be readily modified as needed. 11,12,18,19 Along with the development of inkjet printing technology, the progression of organic semiconductor-based inks has tracked closely behind. In particular, inks based on poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) have witnessed remarkable development since the last decade.…”

An Iminostilbene Functionalized Benzimidazoline for Enhanced n‐Type Solution Doping of Semiconducting Polymers for Organic Thermoelectrics

“…[ 6 ] These devices are foreseen to play a central role in the field of the Internet of Things (IoT) as ideal supply systems for low‐power, distributed electronics with room temperature applications, substituting or extending the lifetime of standard batteries. [ 7 ] The thermoelectric properties of a material are defined by the figure of merit zT = ( σS 2 /κ) T , where S is the Seebeck coefficient, κ is the thermal conductivity, and T is the average temperature. Due to their disordered structure suppressing phononic transport, organic materials have the advantage of intrinsically possessing a low κ < 1 W m −1 K −1 .…”

“…[6] These devices are foreseen to play a central role in the field of the Internet of Things (IoT) as ideal supply systems for low-power, distributed electronics with room temperature applications, substituting or extending the lifetime of standard batteries. [7] The thermoelectric properties of a material are defined by the figure of merit zT = (σS 2 /κ)T, where S is Doped organic semiconductors play a central role in the development of several innovative optoelectronic and energy harvesting applications. Currently, the realization of thermoelectric generators, which require both hole-and electron-transporting materials with high electrical conductivity, is strongly hindered by the scarce availability of stable solution-processable n-dopants and their limited efficiency.…”