Conductive PEDOT: PSS-Based Organic/Inorganic Flexible Thermoelectric Films and Power Generators

We present a simple thermoelectric device that consists of a conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based inorganic/organic thermoelectric film with high thermoelectric performance. The PEDOT:PSS-coated Se NWs were first chemically synthesized in situ, and then mixed with an Ag precursor solution to produce the PEDOT:PSS-coated Ag2Se NWs. The PEDOT:PSS matrix was then treated with dimethyl sulfoxide (DMSO) prior to the production of flexible PEDOT:PSS-coated Ag2Se NW/PEDOT:PSS composite films with various weight fractions of Ag2Se via a simple drop-casting method. The thermoelectric properties (Seebeck coefficient, electrical conductivity, and power factor) of the composite films were then analyzed. The composite film with 50 wt.% NWs exhibited the highest power factor of 327.15 μW/m·K2 at room temperature. The excellent flexibility of this composite film was verified by bending tests, in which the thermoelectric properties were reduced by only ~5.9% after 1000 bending cycles. Finally, a simple thermoelectric device consisting of five strips of the proposed composite film was constructed and was shown to generate a voltage of 7.6 mV when the temperature difference was 20 K. Thus, the present study demonstrates that that the combination of a chalcogenide and a conductive composite film can produce a high-performance flexible thermoelectric composite film.

Chitosan/Polyethylene Oxide (PEO) Filled Carbonized Wood Fiber Conductive Composite Film

Biopolymer-based conductive polymer composites (CPCs) would open up various possibilities in biomedical applications owing to ease of processing, renewable resource and environmentally friendly. However, low mechanical properties are a major issue for their applications. In this study, the investigated the conductivity of chitosan/ PEO blend films filled with carbonized wood fiber (CWF) prepared by solution casting. The effect of CWF was also investigated on tensile properties and their morphological surfaces. The tensile results from different ratios of chitosan/PEO blend films without CWF show that the tensile strength and modulus increased with the increase of chitosan content and chitosan/PEO blend film with 70/30 ratio exhibited the best combination of tensile strength and flexibility. However, a reduction of tensile strength was observed when CWF amount was increased while the modulus of the tensile shows an increment. The film also exhibited higher electrical conductivity as compared to low chitosan ratio. The addition of CWF greatly enhanced the conductivity three-fold from 10-10 to 10-6 S/cm. The electrical conductivity continued to increase with the increase of CWF up to 30wt%. The surface morphology by Scanning Electron Microscopy (SEM) exhibits the absence of phase separation for the blends indicating good miscibility between the PEO and chitosan. Incorporation of CWF into the blend films at 5wt% showed agglomeration. However, the increase of CWF created larger agglomerations that formed conductive pathways resulting in improved conductivity. FTIR analysis suggested that intermolecular interactions occurred between chitosan and PEO while CWF interacts more with the protons of PEO.