Thermally Enhanced n‐Type Thermoelectric Behavior in Completely Organic Graphene Oxide‐Based Thin Films

Cho, Chungyeon; Bittner, Noah; Choi, Woongchul; Hsu, Jui-Hung; Yu, Choongho; Grunlan, Jaime C.

doi:10.1002/aelm.201800465

Cited by 29 publications

(45 citation statements)

References 78 publications

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“…It was interesting to see that both the electrical conductivity and Seebeck coefficient increased simultaneously with increasing layers, which was different from the conventional inorganic TE materials that displayed an inverse relationship. The decoupled behavior in the TE properties could be attributed to improved carrier mobility as previously studied in the multilayer systems [60,61]. Based on the measured electrical conductivity and Seebeck coefficient, the power factor (PF = S 2 •σ) was calculated as a function of layers deposited.…”

Section: Thermoelectric Propertiesmentioning

confidence: 81%

Organic Thermoelectric Multilayers with High Stretchiness

Cho

Son

2019

Nanomaterials

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A stretchable organic thermoelectric multilayer is achieved by alternately depositing bilayers (BL) of 0.1 wt% polyethylene oxide (PEO) and 0.03 wt% double walled carbon nanotubes (DWNT), dispersed with 0.1 wt% polyacrylic acid (PAA), by the layer-by-layer assembly technique. A 25 BL thin film (~500 nm thick), composed of a PEO/DWNT-PAA sequence, displays electrical conductivity of 19.6 S/cm and a Seebeck coefficient of 60 µV/K, which results in a power factor of 7.1 µW/m·K2. The resultant nanocomposite exhibits a crack-free surface up to 30% strain and retains its thermoelectric performance, decreasing only 10% relative to the unstretched one. Even after 1000 cycles of bending and twisting, the thermoelectric behavior of this nanocomposite is stable. The synergistic combination of the elastomeric mechanical properties (originated from PEO/PAA systems) and thermoelectric behaviors (resulting from a three-dimensional conjugated network of DWNT) opens up the possibility of achieving various applications such as wearable electronics and sensors that require high mechanical compliance.

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Section: Thermoelectric Propertiesmentioning

confidence: 81%

Organic Thermoelectric Multilayers with High Stretchiness

Cho

Son

2019

Nanomaterials

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“…The use of SWCNTs is, however, restricted due to the more complex fabrication processes and the difficulty of separating the semiconducting species from the poorer performing metallic SWCNTs [ 47 , 48 ]. On the other hand, reduced graphene oxide films have been measured to have S ~ −90 μV K −1 [ 49 ], thus showing promise for sensing applications as described here. They are, however, again hindered by fabrication processes more complex than what is reported for the multilayer graphene films presented in this work.…”

Section: Discussionmentioning

confidence: 99%

Large-Area Thermal Distribution Sensor Based on Multilayer Graphene Ink

Koskinen

Juntunen

Tittonen

2020

Sensors

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Emergent applications in wearable electronics require inexpensive sensors suited to scalable manufacturing. This work demonstrates a large-area thermal sensor based on distributed thermocouple architecture and ink-based multilayer graphene film. The proposed device combines the exceptional mechanical properties of multilayer graphene nanocomposite with the reliability and passive sensing performance enabled by thermoelectrics. The Seebeck coefficient of the spray-deposited films revealed an inverse thickness dependence with the largest value of 44.7 μV K−1 at 78 nm, which makes thinner films preferable for sensor applications. Device performance was demonstrated by touch sensing and thermal distribution mapping-based shape detection. Sensor output voltage in the latter application was on the order of 300 μV with a signal-to-noise ratio (SNR) of 35, thus enabling accurate detection of objects of different shapes and sizes. The results imply that films based on multilayer graphene ink are highly suitable to thermoelectric sensing applications, while the ink phase enables facile integration into existing fabrication processes.

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“…The reason for this high ZT value was mainly based on the enhancement of electrical conductivity and the Seebeck coefficient of PEDOT:PSS after DMSO aligns with the PEDOT chain. The hybrid composite of reduced graphene oxide (rGO)/CNT and polymers also showed improved‐thermoelectrical properties compared to the pure polymers by increasing the conductivity of the active materials . Additionally, mixing polymers with inorganic TMs was another effective way to enhance the thermoelectrical property of the polymer matrix .…”

Section: Materials For Energy Conversion Devicesmentioning

confidence: 99%

Fiber‐Based Energy Conversion Devices for Human‐Body Energy Harvesting

et al. 2019

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body is actually a tremendous storehouse of energy that is generated from body heat and motion. [15][16][17][18][19] Power generation from breathing, heating, blood transport, arm motion, typing, and walking could reach to over 100 W for a 68 kg adult's daily activities (Figure 1). [20] Thus, converting 1% of power from the human body may be enough to support the work of most portable electronics.In the past two decades, researchers have developed several energy conversion devices based on piezoelectricity, electrostaticity, triboelectricity, or thermoelectricity that can directly harvest the mechanical or thermal energy and convert it into electric energy (these conversion devices are so-called nanogenerators (NGs)). [21][22][23][24][25] The first nanogenerator (NG) based on ZnO was invented by Prof. Wang in 2006; after that, various NGs were developed to harvest the mechanical or thermal energy with the output performance increasing gradually. [26] These NGs are easy-to-construct flexible devices since most materials for these devices are polymers and nanomaterials. Generally, the flexible devices assembled by film materials can be stretchable and bendable in one direction. But their lack of air-permeability, poor 3D deformation, and low damage tolerance limit their application, especially for wearable electronics. Therefore, fiberbased energy conversion devices have been designed. [27] These fiber-based devices can also be knitted to yarn or fabric in the clothing system to build up a large area electronic system. [28,29] The energy generation and internal charging can be realized by means of a self-powered system that harvests the energy from natural sources around the human body to sustain the wearable electronics. [30][31][32] The search for functional materials that possess good conversion efficiency, as well as great mechanical and environmental stability, combined with a novel device design might push these devices to meet the requirement of a practical application. In the past decade, numerous contributions have been offered to improve the performance of fiber-based energy conversion devices (FBECD) and extend its application. This review specifically summarizes FBECD with different energy conversion mechanisms including piezoelectricity, electrostaticity, triboelectricity, and thermoelectricity in recent processes (Figure 2). The functional materials, fiber fabrication techniques, and device design strategies for different classes of FBECDs are covered in the article. We also introduce an overview of the fiber-based self-powered system and sensors and Following the rapid development of lightweight and flexible smart electronic products, providing energy for these electronics has become a hot research topic. The human body produces considerable mechanical and thermal energy during daily activities, which could be used to power most wearable electronics. In this context, fiber-based energy conversion devices (FBECD) are proposed as candidates for effective conversion of human-body energy into electricity...

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Thermally Enhanced n‐Type Thermoelectric Behavior in Completely Organic Graphene Oxide‐Based Thin Films

Cited by 29 publications

References 78 publications

Organic Thermoelectric Multilayers with High Stretchiness

Organic Thermoelectric Multilayers with High Stretchiness

Large-Area Thermal Distribution Sensor Based on Multilayer Graphene Ink

Fiber‐Based Energy Conversion Devices for Human‐Body Energy Harvesting

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