Structure Design for High Performance n-Type Polymer Thermoelectric Materials

Organic thermoelectric (OTE) materials have been regarded as a potential candidate to harvest waste heat from complex, low temperature surfaces of objects and convert it into electricity. Recently, n-type conjugated polymers as organic thermoelectric materials have aroused intensive research in order to improve their performance to match up with their p-type counterpart. In this review, we discuss aspects that affect the performance of n-type OTEs, and further focus on the effect of planarity of backbone on doping efficiency and eventually the TE performance. We then summarize strategies such as implementing rigid n-type polymer backbone or modifying conventional polymer building blocks for more planar conformation. In the outlook part, we conclude forementioned devotions and point out new possibility that may promote the future development of this field.

Effect of Crystalline Microstructure Evolution on Thermoelectric Performance of PEDOT : PSS Films

Although organic polymer thermoelectric (TE) materials have witnessed explosive advances in the recent decade, the molecular mechanism of crystallization engineering of TE performance, even for the most successful polymer of poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS), is still far from clear. Here, we deepen the understanding of the role of annealing-induced crystalline microstructure evolution on TE performance of the PEDOT : PSS film with thickness of 10 μm, which is usually more effective than thin ones in applications. Annealed at optimized temperature of 220°C, the film displays a power factor of 162.5 times of that of the pristine film before annealing. The enhanced TE performance is associated with the changes of crystallographic and morphologic microstructures, including increased crystallinity and crystal grain size, a domain morphology transformation from granular to crystalline nanofibril, and reduced insulating PSS in the skin layer. These variances facilitate the carrier transport by a transition from 3D to 1D hopping, reduce the activation energy, and improve the carrier mobility. The mechanism of crystallization engineering reported here can be conceptually extended to other TE polymers and guides the future rational design of preparation principles for organic and composite TE materials.

High thermal conductivity states and enhanced figure of merit in aligned polymer thermoelectric materials

Control of morphology in polymer thermoelectric materials is critical to their performance. In this work we study highly aligned polymer thermoelectric materials prepared by mechanical rubbing. We observe a remarkable...

The contemporary role of metastasectomy in the management of metastatic RCC

Significant progress has been achieved for flexible polymer thermoelectric (TE) composites in the recent decade due to their potential application in wearable devices and sensors. In sharp contrast with the booming TE studies at room temperature, the TE performances of polymer TE composites received relatively less attention despite the significance for the application of TE composites in the high temperature environments. The TE and mechanical performances of flexible poly (3,4 ethylenedioxythiophene):poly(styrene sulfonate)/single-walled carbon nanotube (PEDOT:PSS/SWCNT) composite films with ionic liquid (IL) (refer to as “PEDOT:PSS/SWCNT-IL”) at high temperatures are studied in the present work. The resultant composite film shows the increasing TE performances with increasing temperatures and SWCNT contents. The maximum value of the power factor reaches 301.35 W m-1 K-2 at 470 K for the PEDOT:PSS/SWCNT-IL composite. Besides, the addition of IL can improve the elongation at break of composites compared to the IL-free composites. This work promotes the advance of flexible polymer TE composites and widens the potential applications at different temperature ranges.

A Water-Dispersible Quinoid-Resonant Conducting Polymer for Organic Electronics

Developing stable and solution-processable highly conductive polymers has been the research goal in organic electronics since the first demonstration of metallic conductive polyacetylene. Here, we used a unique quinoid-resonant building block thieno[3,4-b]thiophene (TbT) to develop a new water-dispersible conducting polymer, PTbT-Me:PSS. Linear polymerization and large surfactant counterion, poly(styrenesulfonate) (PSS−), were introduced, which enabled a high electrical conductivity of 68 S cm−1 and exhibited water-dispersible property. Interchain bipolaron was found in PTbT-Me:PSS when compared with polaron in PEDOT:PSS in their conducting mechanism. Moreover, we applied this highly conductive PTbT-Me:PSS as the solution-processed polymer thermoelectric material and a decent power factor of 3.1 μW m−1 K−2 was achieved.