Nanoscale Thermal Management of Single SnO 2 Nanowire: pico-Joule Energy Consumed Molecule Sensor

2019

RSC Adv.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Growth mechanism of SnC₂H₄O₂ nanowires prepared by the polyol process as SnO₂ precursor nanowires

Park

2019

RSC Adv.

Journal of Applied Physics

“…Thermal engineering of nanostructured materials has attracted much attention due to their close relevance to thermoelectric applications and various kinds of nanodevices, including transistors, 1 light-emitting-diodes, and sensors. 2 Since the heat energy in semiconductors and dielectrics is mostly carried by phonons, understanding the phonon transport characteristics is critical for thermal engineering. 3 However, directly probing or measuring the essential phonon characteristics, including the frequency x, specific heat C p , propagating velocity v, and mean free path K, has been a universal challenge because the measurable thermal conductivity j values always contain all these contributions from activated phonon modes in the Brillouin zone:…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity of Si nanowires with δ-modulated dopant distribution by self-heated 3ω method and its length dependence

Zhuge

Takahashi

Kanai

et al. 2018

Self Cite

Here, we report the thermal conductivity measurement of B-doped Si nanowires with d dopant modulation on the surface using the self-heated 3x method, which resembles the thermal dissipation in operating electronic devices. The thermal conductivity for d-modulated Si nanowires of 45 nm diameter ($23 W/m K) is found to agree well with that of non-doped Si nanowires reported previously, which is attributed to the dominant surface boundary scattering and the highly confined dopant distribution at the surface. Furthermore, through a length dependent study of the thermal conductivity (j) from 400 nm to 4 lm, we found an apparent length dependence of j at L < 2 lm. The phenomenon could not be simply interpreted by solely considering the ballistic effect in thermal transport, but can be accounted for by including the additional resistive processes that are associated with the thermalization of joule-heating emitted phonons, which opts in to suppress the thermal conductivity of nano-systems under the ballistic thermal transport regime.

“…The overall process was described in Figure S14 in the Supporting Information. [52] Wireless transmission of the sensor signals can be also realized in near future because the power consumption of the bluetooth transmitter decreases down to several mW and further decrease can be expected soon. Although the operating temperature of the sensor was reached by an external power source, it is believed that the power required to maintain the sensors at the high temperature can decrease to several µW.…”

Section: Resultsmentioning

confidence: 99%

High‐Output Triboelectric Nanogenerator Based on Dual Inductive and Resonance Effects‐Controlled Highly Transparent Polyimide for Self‐Powered Sensor Network Systems

Jung

Advanced Energy Materials

et al. 2019

Internet of things (IoT), has triggered considerable interest in triboelectric nanogenerators (TENGs) as renewable and sustainable power sources, [1][2][3][4] owing to their high output power, [5,6] cost-effectiveness, [7] and high energy conversion efficiency. [8][9][10] The wide-availability and high functionality of TENGs offers itself to several practical applications. [11][12][13][14] Crucial to the successful implementation of TENGs in practical applications is to generate sufficient output power, usually stored in a capacitor or a battery, to operate the devices. [15][16][17][18] Strategies to enhance the output performance of TENGs are generally based on increasing of the transferred charge density between two contacted surfaces, as the electric potential is critically dependent on it. [19][20][21][22] Although the principle of contact-electrification has long been studied, [23][24][25] but whose mechanisms are still unclear. Recently, surface-states and electron cloud/potential models have been employed to explain the contact electrification mechanism. However, these models are limited to metal-semiconductors and metal-insulators, i.e., they may be not currently compatible with metal-polymers. [26,27] Other strategies have relied on the choice of materials in the triboelectric series with electronic and structural modifications, [28] such as a large work-function difference, [29,30] high porosity, [31,32] large dielectric constant, [33][34][35] and large surface roughness. [36][37][38] The maximum charge density of these TENGs in practical environments, however, requires additional processes, such as charges injection and poling process under high electric field. [35,[39][40][41] In particular, the injection process was quite efficient in increasing the charge density because it was considered to be limited by air breakdown. [38] Actually, the dielectric strengths of the polymers are larger than that of the air. The charge density was reached to 260 and 283 µC m −2 in TENGs with single-layered film and multilayered film, respectively. [40,41] Recently, several modifications to amplify the current flowing through the external circuit have been successfully demonstrated. [6,20,42] Metal-dielectric-metal structures or metal-metal contacts have been introduced, proven to increase the charge density of the TENG by several times.Since TENGs are driven by vibrations in the environment and human kinetics, the frequencies of the mechanical forces High-output triboelectric nanogenerators (TENGs) are demonstrated based on polyimide (PI)-based polymers by introducing functionalities (e.g., electronwithdrawing and electron-donating groups) into the backbone. The TENG based on 6FDA-APS PI, possessing the most negative electrostatic potential and the low-lying lowest unoccupied molecular orbital level, produces the highest effective charge density of about 860 µC m −2 in practical working conditions with the ion injection process. This may be ascribed to the excellent charge-retention characteristics as well as the enh...