Flexible thermoelectric materials and devices

In the development of next-generation materials with enhanced thermal properties, biological systems in nature provide many examples that have exceptional structural designs and unparalleled performance in their thermal or nonthermal functions. Bioinspired engineering thus offers great promise in the synthesis and fabrication of thermal materials that are difficult to engineer through conventional approaches. In this review, recent progress in the emerging area of bioinspired advanced materials for thermal science and technology is summarized. State-of-the-art developments of bioinspired thermal-management materials, including materials for efficient thermal insulation and heat transfer, and bioinspired materials for thermal/infrared detection, are highlighted. The dynamic balance of bioinspiration and practical engineering, the correlation of inspiration approaches with the targeted applications, and the coexistence of molecule-based inspiration and structure-based inspiration are discussed in the overview of the development. The long-term outlook and short-term focus of this critical area of advanced materials engineering are also presented.

Bioinspired Engineering of Thermal Materials

Semimetals are being explored for their unique advantages in low-energy high-speed photodetection, although they suffer from serious drawbacks such as an intrinsically high dark current. In this Perspective, we envision the exploitation of topological effects in the photoresponse of these materials as a promising route to circumvent these problems. We overview recent studies on photodetection based on graphene and other semimetals, and further discuss the opportunities created by topological effects, along with the additional challenges that they impose on photodetector designs.

Semimetals for high-performance photodetection

Photodetectors play key roles in many applications such as remote sensing, night vision, reconnaissance, medical imaging, thermal imaging, and chemical detection. Several properties such as performance, reliability, ease of integration, cost, weight, and form factor are all important in determining the attributes of photodetectors for particular applications. While a number of materials have been used over the past several decades to address photo­detection needs across the electromagnetic spectrum, the advent of nanomaterials opens new possibilities for photodetectors. In particular, carbon-based nanomaterials such as carbon nanotubes (CNTs) and graphene possess unique properties that have recently been explored for photodetectors. Here, the status of the field is reviewed, presenting a broad coverage of the different types of photodetectors that have been realized with CNTs, placing particular emphasis on the types of mechanisms that govern their operation. A comparative summary is presented of the main performance metrics for such detectors, and an outlook for performance improvements.

Uncooled Carbon Nanotube Photodetectors

Ultrathin plasmonic metasurfaces have proven their ability to control and manipulate light at unprecedented levels, leading to exciting optical functionalities and applications. Although to date metasurfaces have mainly been investigated from an electromagnetic perspective, their ultrathin nature may also provide novel and useful mechanical properties. Here we propose a thin piezoelectric plasmonic metasurface forming the resonant body of a nanomechanical resonator with simultaneously tailored optical and electromechanical properties. We experimentally demonstrate that it is possible to achieve high thermomechanical coupling between electromagnetic and mechanical resonances in a single ultrathin piezoelectric nanoplate. The combination of nanoplasmonic and piezoelectric resonances allows the proposed device to selectively detect long-wavelength infrared radiation with unprecedented electromechanical performance and thermal capabilities. These attributes lead to the demonstration of a fast, high-resolution, uncooled infrared detector with ∼80% absorption for an optimized spectral bandwidth centered around 8.8 μm.

https://escholarship.org/content/qt1n4480pg/qt1n4480pg.pdf?t=qakdta

Plasmonic piezoelectric nanomechanical resonator for spectrally selective infrared sensing

During the last few years, thermopiles have come increasingly under the spotlight of commercial infrared sensing. This growing interest has motivated us to write an overview of micromachined thermopiles. The first part deals with the Seebeck effect and discusses the most important physical parameters with their interactions. We also describe the main noise sources and give a derivation of the figures of merit and their relevance for thermopile detectors. In the second part, a number of material systems, techniques and micromachined structures are discussed on the basis of different examples. We explain the motivation behind miniaturized thermopile detectors and give a functional explanation of physical interrelations. Finally, different applications are presented and discussed in terms of their future potential.

http://iopscience.iop.org/article/10.1088/0957-0233/18/7/R01/pdf

Review of micromachined thermopiles for infrared detection

The mobile telephone (2) has an integrated radiation temperature sensor (1) with evaluation electronics (6) for preparing temperature data for the transmission over the mobile telephone. The radiation temperature sensor is arranged such that the radiation striking on the mobile telephone from outside, is evaluated.

Mobile telephone for collection and transmission of medical relevant data, has integrated radiation temperature sensor with evaluation electronics for preparing temperature data for transmission over mobile telephone

The invention relates to a device for controlling a ventilation device for a motor vehicle interior ( 36 ), comprising at least one air quality sensor ( 46 ) for generating an air quality signal of the air supplied to the air quality sensor ( 46 ), an actuator for adjusting an air damper ( 20 a , 20 b ) of the ventilation device as a function of the air quality signal, and a ventilator ( 14 ) for transporting the air through the ventilation device into the motor vehicle interior ( 36 ). The air quality sensor ( 46 ) and the ventilator ( 14 ) form a structural unit ( 44 ).

Device for controlling the ventilation apparatus for a motor vehicle interior

Die
Erfindung betrifft einen Trockner zum Trocknen mindestens eines
Objektes (4), wobei der Trockner (1) aufweist: ein Trocknergehause (2),
in dem ein Trockenraum (3) zur Aufnahme des mindestens einen Objektes
(4) vorgesehen ist, eine Heizung (7) zum Heizen des Trockenraums
(3), ein infrarotsensitives Messelement (9) zur beruhrungslosen
spektroskopischen Messung der Oberflachentemperatur des in dem Trockenraum
(3) vorgesehenen Objektes (4) und Ausgabe eines Oberflachen-Temperatursignals
(To), und eine Steueranordnung (11) mit einer ersten Steuereinrichtung
(11) zur Aufnahme des Oberflachen-Temperatursignals
(To) von dem infrarotsensitiven Messelement (9) und einer zweiten
Steuereinrichtung (11) zur Steuerung oder Regelung der Heizung (7), wobei
die Steueranordnung (11) aus zumindest dem Oberflachen-Temperatursignal
(To) auf einen Feuchtegrad des mindestens einen Objektes (4) schliest. Hierbei
sind die erste und zweite Steuereinrichtung vorteilhafterweise als
gemeinsame zentrale Steuereinrichtung (11) ausgebildet.

Trockner und Verfahren unter Verwendung des Trockners

The invention relates to a photometric gas sensor, containing at least one infrared radiation source (a) and a first reflector (R1) for deflecting infrared radiation, originating from an infrared radiation source (a), to a second reflector (R3a, R3b), which deflects the radiation originating from the first reflector to an infrared detector (b).

Maximilian Sauer

Papers

Review of micromachined thermopiles for infrared detection

Mobile telephone for collection and transmission of medical relevant data, has integrated radiation temperature sensor with evaluation electronics for preparing temperature data for transmission over mobile telephone

Device for controlling the ventilation apparatus for a motor vehicle interior

Trockner und Verfahren unter Verwendung des Trockners

Reflector module for a photometric gas sensor