High-performance flat-panel solar thermoelectric generators with high thermal concentration
TL;DR: A promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration is demonstrated, thus enabling wider applications and opening up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.
Abstract: The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. A highly efficient solar to electric energy conversion device based on nanostructured thermoelectric materials and high solar concentration is now demonstrated. The results show potential for cost effective solar thermoelectric generation.
Citations
More filters
TL;DR: The latest successful examples of flexible and stretchable physical sensors for the detection of temperature, pressure, and strain, as well as their novel structures, technological innovations, and challenges, are reviewed.
Abstract: Flexible and stretchable physical sensors that can measure and quantify electrical signals generated by human activities are attracting a great deal of attention as they have unique characteristics, such as ultrathinness, low modulus, light weight, high flexibility, and stretchability. These flexible and stretchable physical sensors conformally attached on the surface of organs or skin can provide a new opportunity for human-activity monitoring and personal healthcare. Consequently, in recent years there has been considerable research effort devoted to the development of flexible and stretchable physical sensors to fulfill the requirements of future technology, and much progress has been achieved. Here, the most recent developments of flexible and stretchable physical sensors are described, including temperature, pressure, and strain sensors, and flexible and stretchable sensor-integrated platforms. The latest successful examples of flexible and stretchable physical sensors for the detection of temperature, pressure, and strain, as well as their novel structures, technological innovations, and challenges, are reviewed first. In the next section, recent progress regarding sensor-integrated wearable platforms is overviewed in detail. Some of the latest achievements regarding self-powered sensor-integrated wearable platform technologies are also reviewed. Further research direction and challenges are also proposed to develop a fully sensor-integrated wearable platform for monitoring human activity and personal healthcare in the near future.
1,469 citations
TL;DR: Lewis reviews the status of solar thermal and solar fuels approaches for harnessing solar energy, as well as technology gaps for achieving cost-effective scalable deployment combined with storage technologies to provide reliable, dispatchable energy.
Abstract: Major developments, as well as remaining challenges and the associated research opportunities, are evaluated for three technologically distinct approaches to solar energy utilization: solar electricity, solar thermal, and solar fuels technologies. Much progress has been made, but research opportunities are still present for all approaches. Both evolutionary and revolutionary technology development, involving foundational research, applied research, learning by doing, demonstration projects, and deployment at scale will be needed to continue this technology-innovation ecosystem. Most of the approaches still offer the potential to provide much higher efficiencies, much lower costs, improved scalability, and new functionality, relative to the embodiments of solar energy-conversion systems that have been developed to date.
1,416 citations
Cites background from "High-performance flat-panel solar t..."
...Thermoelectrics could also serve as the technology that converts heat into electricity, provided that their performance can be improved to the necessary levels under the high temperatures that are produced in an operational solar thermal system (5, 69)....
[...]
TL;DR: In this article, Minnich et al. reviewed the progress made in thermoelectrics over the past two years on charge and heat carrier transport, strategies to improve the thermiolectric figure of merit, with new discussions on device physics and applications.
Abstract: This review is an update of a previous review (A. J. Minnich, et al., Energy Environ. Sci., 2009, 2, 466) published two years ago by some of the co-authors, focusing on progress made in thermoelectrics over the past two years on charge and heat carrier transport, strategies to improve the thermoelectric figure of merit, with new discussions on device physics and applications, and assessing challenges on these topics. Understanding of phonon transport in bulk materials has advanced significantly as the first-principles calculations are applied to thermoelectric materials, and experimental tools are being developed. Some new strategies have been developed to improve electron transport in thermoelectric materials. Fundamental questions on phonon and electron transport across interfaces and in thermoelectric materials remain. With thermoelectric materials reaching high ZT values well above one, the field is ready to take a step forward and go beyond the materials' figure of merit. Developing device contacts and module fabrication techniques, developing a platform for efficiency measurements, and identifying applications are becoming increasingly important for the future of thermoelectrics.
1,049 citations
TL;DR: The intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices is reported, providing strong evidence that nonlocal hot carrier transport, rather than the photovoltaic effect, dominates the intrinsic photoresponse in graphene.
Abstract: We report on the intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices. Local laser excitation (of wavelength 850 nanometers) at the p-n interface leads to striking six-fold photovoltage patterns as a function of bottom- and top-gate voltages. These patterns, together with the measured spatial and density dependence of the photoresponse, provide strong evidence that nonlocal hot carrier transport, rather than the photovoltaic effect, dominates the intrinsic photoresponse in graphene. This regime, which features a long-lived and spatially distributed hot carrier population, may offer a path to hot carrier–assisted thermoelectric technologies for efficient solar energy harvesting.
967 citations
TL;DR: Various approaches for energy harvesting to meet the future demand for self-powered MNSs are covered.
Abstract: Health, infrastructure, and environmental monitoring as well as networking and defense technologies are only some of the potential areas of application of micro-/nanosystems (MNSs). It is highly desirable that these MNSs operate without an external electricity source and instead draw the energy they require from the environment in which they are used. This Review covers various approaches for energy harvesting to meet the future demand for self-powered MNSs.
907 citations
References
More filters
TL;DR: A new era of complex thermoelectric materials is approaching because of modern synthesis and characterization techniques, particularly for nanoscale materials, and the strategies used to improve the thermopower and reduce the thermal conductivity are reviewed.
Abstract: Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state Peltier coolers, could play an important role in a global sustainable energy solution. Such a development is contingent on identifying materials with higher thermoelectric efficiency than available at present, which is a challenge owing to the conflicting combination of material traits that are required. Nevertheless, because of modern synthesis and characterization techniques, particularly for nanoscale materials, a new era of complex thermoelectric materials is approaching. We review recent advances in the field, highlighting the strategies used to improve the thermopower and reduce the thermal conductivity.
8,999 citations
TL;DR: Th thin-film thermoelectric materials are reported that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys, and the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications.
Abstract: Thermoelectric materials are of interest for applications as heat pumps and power generators. The performance of thermoelectric devices is quantified by a figure of merit, ZT, where Z is a measure of a material's thermoelectric properties and T is the absolute temperature. A material with a figure of merit of around unity was first reported over four decades ago, but since then-despite investigation of various approaches-there has been only modest progress in finding materials with enhanced ZT values at room temperature. Here we report thin-film thermoelectric materials that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys. This amounts to a maximum observed factor of approximately 2.4 for our p-type Bi2Te3/Sb2Te3 superlattice devices. The enhancement is achieved by controlling the transport of phonons and electrons in the superlattices. Preliminary devices exhibit significant cooling (32 K at around room temperature) and the potential to pump a heat flux of up to 700 W cm-2; the localized cooling and heating occurs some 23,000 times faster than in bulk devices. We anticipate that the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications: for example, in thermochemistry-on-a-chip, DNA microarrays, fibre-optic switches and microelectrothermal systems.
4,921 citations
TL;DR: Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconductor properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating.
Abstract: Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconducting properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating. These materials can be competitive with fluid-based systems, such as two-phase air-conditioning compressors or heat pumps, or used in smaller-scale applications such as in automobile seats, night-vision systems, and electrical-enclosure cooling. More widespread use of thermoelectrics requires not only improving the intrinsic energy-conversion efficiency of the materials but also implementing recent advancements in system architecture. These principles are illustrated with several proven and potential applications of thermoelectrics.
4,700 citations
"High-performance flat-panel solar t..." refers background in this paper
...Conventional wisdom is that thermoelectrics are most suitable for waste heat recovery and that materials with significantly higher ZT are needed for large-scale application...
[...]
TL;DR: Electrical transport measurements, coupled with microstructure studies and modeling, show that the ZT improvement is the result of low thermal conductivity caused by the increased phonon scattering by grain boundaries and defects, which makes these materials useful for cooling and power generation.
Abstract: The dimensionless thermoelectric figure of merit (ZT) in bismuth antimony telluride (BiSbTe) bulk alloys has remained around 1 for more than 50 years. We show that a peak ZT of 1.4 at 100°C can be achieved in a p-type nanocrystalline BiSbTe bulk alloy. These nanocrystalline bulk materials were made by hot pressing nanopowders that were ball-milled from crystalline ingots under inert conditions. Electrical transport measurements, coupled with microstructure studies and modeling, show that the ZT improvement is the result of low thermal conductivity caused by the increased phonon scattering by grain boundaries and defects. More importantly, ZT is about 1.2 at room temperature and 0.8 at 250°C, which makes these materials useful for cooling and power generation. Cooling devices that use these materials have produced high-temperature differences of 86°, 106°, and 119°C with hot-side temperatures set at 50°, 100°, and 150°C, respectively. This discovery sets the stage for use of a new nanocomposite approach in developing high-performance low-cost bulk thermoelectric materials.
4,695 citations
Journal Article•
4,230 citations