THERMOELECTRIC MATERIALS

Thermoelectric Devices (Flexible and/or transparent)

  • Fully transparent TE devices (able to draw ~10nWs power from small temperature gradients – for IoT and wearable device applications)
  • Flexible TE devices 
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1. Modeling Charge transport in conducting polymers 

  • Promote the understanding of charge transport in conducting polymers
  • Establish the design principles for making novel organic thermoelectric
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2. Measurement of Thermoelectric bulk and thin films 

A. High TE performance in PEDOT:PSS polymer films 

  1. High performance organic-based TE materials
  2. Inorganic/Inorganic acid and co-solvent post-treatment strategies
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B. Hybrid thermoelectrics 

High TE performance Hybrid (inorganic-organic composite) materials 

  • Natural halide perovskites with ultra-high Seebeck coefficient (large voltage response to temperature gradient)
  • High TE performance hybrid organic materials
C. Deep understanding of charge and thermoelectric transport in materials – morphology dominates over energy-dependent scattering in hybrid thermoelectrics
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3. Thermoelectric performance of mixed-phase 2D materials 

  • The thermoelectric properties of mixed-phase LixMoS2 have been studied as a function of its phase composition tuned by in situ thermally driven deintercalation
  • It is found that the sign of Seebeck coefficient changes from positive to negative during initial reduction of the 1T/1T’ phase fraction, indicating crossover fromp- to n-type carrier conduction
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    Ng Hong Kuan*, Anas Abutaha* et al, ACS appl. Mat. Int. 11, 12184 (2019)

TE characterization equipment in ELE

1. Thermoelectric characterization system (Bulk and thin film)

  • ZEM3-HR system (Seebeck and electrical conductivity)
  • NanoTR system (Thermal Diffusivity and Thermal Effusivity)
  • Heat capacity 
  • Thermal conductivity
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2. Micro-fabricated devices for temperature –dependent thermoelectric measurements of thin films

  • Developed a new and accurate technique to measure temperature dependent in-plane Seebeck coefficient and electrical conductivity of organic and inorganic thin films
  • The measurement device consists of one heater, two thermometers, and a four-probe configuration which is patterned on a substrate of choice using a simple shadow mask.
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Pawan Kumar et al,Rev. Sci. Instrum. 88, 125112 (2017)

3. Liquid He closed cycle high vacuum cryostat 

  • Temperature-dependent thermoelectric measurements
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(Janis and Keithley electronics)

4.Physical Properties Measurement System (PPMS)

Offering a wide range of magnetic, thermal and electrical measurements

  • Temperature 

Range: 1.9-400 K

Sensitivity: 0.01 K

  • Magnetic field: +/- 9 T

sensitivity: 0.1 Oe

ramp rate: 1-200 Oe/sec

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(Quantum  Design)