Organic Thermoelectric Multilayers with High Stretchiness

Abstract

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.

Organic-based flexible thermoelectric generators: From materials to devices

“…33(h) shows the SEM image of the fabricated layer's cross section [467]. The LbL technique has been applied to many organic TE materials and their composites to fabricate flexible TEGs, examples are PEDOT:PSS/ce-MoS 2 [367], polyethylene oxide (PEO)/DWCNT/polyacrylic acid (PAA) [468], PEDOT:PSS/polyethyleneimine/cellulose nanofiber [38], graphene nanoplatelet/SWCNT/poly(vinyl alcohol (PVA)/poly (diallyldimethyl ammonium chloride) (PDDA) [469], MWCNT/PEDOT [470], PEDOT nanoparticle/SWCNT, MWCNT, and DWCNT [471].…”

Thermoelectric Materials: Current Status and Future Challenges

“…For example, Cho and Son fabricated a stretchable thermoelectric multilayer film by alternately depositing 0.1 wt% polyethylene oxide (PEO) and 0.03 wt% DWNT, dispersed with 0.1 wt% polyacrylic acid (PAA). (Cho and Son, 2019) Because of the weak bond strength and high chain mobility between PEO and PAA layers, the PEO/DWNT-PAA multi-layered composite exhibits a crack-free surface up to 30% strain and retains its thermoelectric performance 90% of unstretched sample.…”

Organic Thermoelectric Nanocomposites Assembled via Spraying Layer-by-Layer Method

“…The LbL method has been utilized for developing multifunctional thin films including bio-film inhabitation, flame retardant, gas sensors, and solar cells [18,34]. LbL coatings are mainly based on electrostatic interactions through charge compensation between oppositely charged components, but other interactions including hydrophobic, van der Waals interactions, π-π interactions, and hydrogen bonding are also employed to form ultra-thin films on various types of substrates [35][36][37][38][39].…”