Vitamin C-Induced Enhanced Performance of PEDOT:PSS Thin Films for Eco-Friendly Transient Thermoelectrics

Abstract

Conjugated polymer-based energy-harvesting devices hold distinctive advantages in terms of low toxicity, high flexibility, and capability of large-area integration at low cost for sustainable development. An organic thermoelectric (OTE) device has been considered one of the promising energy-harvesting candidates in recent years because it can efficiently convert low-temperature waste heat into electricity over its inorganic counterparts. However, a cruel irony is that environmentally toxic solvents and acids are utilized for fabrication and performance improvement of the OTE devices, retarding the development and use of genuinely green energy-harvesting. Here, we present eco-friendly, non-toxic strategies for a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based high-performance OTE device by incorporating a nature-abundant material, vitamin C (VC), as an additive. We found that the intrinsic polar nature and reducing ability of VC induce synergy effects of microstructure alignment with PSS removal and dedoping of PEDOT, leading to simultaneous enhancement of the electrical conductivity (>400 S cm–1) and the Seebeck coefficient (>30 μV K–1) and a resultant high thermoelectric power factor of 51.8 μW m–1 K–2. In addition, inspired by the eco-friendly fabrication process, we further demonstrated a transient OTE device, which can be fully degraded with naturally occurring substances, by fabricating it on a bio-based cellulose acetate substrate. We believe that our eco-friendly strategies from fabrication to disposal of the OTE can be applied to the development of high-performance, wearable, and bio-compatible OTE devices with minimal waste and further trigger the research on genuinely green thermal energy harvesting.

Solution-processed ambipolar organic thin-film transistors and inverters in a single substrate through self-assembled monolayer-treated electrodes

“…In general, stronger peaks in the p-p stacking region indicate an increase in the size of the crystalline domain and thereby improved overlapping of the p-orbitals of the polymer backbone. 36 Therefore, it is reasonable to conclude that PFBT molecules facilitated the charge transport (i) by reducing disorder along the in-plane direction by ordering alkyl chains and (ii) by increasing the crystallinity through the out-of-plane direction.…”

Effects of interfacial area and energetic barrier on thermoelectric performance of PEDOT:PSS–MXene composite films

“…To investigate the TE properties of the PEDOT:PSS-MXene composite films, we measured the α and σ using a customized setup as shown in figure 2(a). The temperature gradient was produced on the films using two Peltier devices, and the absolute temperature T and the generated voltage were measured simultaneously using two T-type thermocouples and the Au probes as described in the Materials and Methods section [5,10]. Figures 2(b) -(d) display α, σ, and PF of the PEDOT:PSS-MXene composite films as a function of the MXene concentration.…”

“…Thermoelectric (TE) generation based on conducting polymers is one of the promising technologies that can harvest low-grade waste heat, which accounts for 50% of the total waste heat [1][2][3]. Their unique properties such as light-weight, low-cost, non-toxicity, solution processability, and flexibility provide compelling advantages over the expensive bulk inorganic counterparts at low-temperature heat sources such as the human body [4,5]. In addition, their relatively lower thermal conductivity (κ) is also advantageous for a higher TE figure of merit ZT = α 2 σT/κ, which determines the heat-to-electricity conversion efficiency, where α and σ are the Seebeck coefficient and the electrical conductivity, respectively [6].…”

The future of electronic materials is…degradable!

“…60 Touch Fig. 5 Bioderived active materials for electronics-Melanine, 43,87 and synthetically derived active materials for electronics-PEDOT:PSS, 31,32,34,48,56,57,59,60,72,75,[88][89][90][91][92][93][94] polyaniline(PANI), 62,95 polyimine, 25,96 (the structure of melanin has been adapted 97 ).…”

“…75 Fast degradability of a thermoelectric device has been demonstrated by combining it with cellulose acetate. 92 Variation of PEDOT, without PSS but selfdoped via a sulfonate group directly connected to the heterocyclic backbone, has been optimized for optoelectronic devices 94 and for regenerative engineering. 91 Electroactive disintegrable polymers are a rarity, although the literature is overloaded with terms, as biodegradable or recyclable, and is visible in the imbalance towards other types of easier chemical approaches as cited.…”