Flexible Thermoelectric 2X-TTA-AgF/SWCNT Composites via Bridging Ionic and Organic Domains

Organic thermoelectric materials offer flexible, solution-processable energy harvestingfor wearable electronics, yet their low power factors (PFs) impede practical applications.Here a dual phase interfacial engineering strategy is presented that decouples thesechannels by integrating organic small molecules (OSMs), thieno[2',3':4,5]thieno[3,2-b]thieno[2,3-d]thiophene (TTA) derivatives, with Ag⁺(Ag) ionic bridges on single-walled carbon nanotubes (SWCNTs) networks. Hybridizing TTA and their derivativeswith SWCNTs affords flexible thermoelectric composites. Subsequent AgF solutiontreatment further strengthens interfacial coupling between the OSMs and SWCNTs. Byintroducing Ag+ and in situ generated Ag nanoparticles, the Seebeck coefficient issignificantly enhanced while maintaining high electrical conductivity, leading toremarkable improvement in composites’ PF value. The optimized 2I-TTA (30%)-AgF/SWCNT films achieve a room temperature PF of 995.37 ± 6.01 μW m−1 K−2, retainover 88.3% of their initial power factor after 10, 000 bending cycles, and sustain stableoutput under temperature gradients up to 160 °C. Thermoelectric generator made of 2I-TTA (30%)-AgF/SWCNT composite and n-type SWCNTs generates a maximumpower density output of 186.79 μW g−1 at ΔT = 50 K. This work establishes metal ion-mediated interfacial engineering as a novel paradigm for high-efficiency, durable, andwearable energy harvesting technologies.Key words: Organic small molecules; Composite thermoelectric materials; Silver;Energy filtering effect; Wearable energy harvesting