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Wearable thermoelectrics (TEs) have recently received increasing attention for their potential to harvest electricity from the skin heat. However, the unconventional form factor of wearable devices (stretchable and large-area) and the bulk nature of TEs call for new processing techniques that exploit the third dimension. Here we propose the direct int writing (DIW) of PEDOT:PSS, one of the best reported organic TE materials, directly on a stretchable substrate. We introduce an extremely easy route to formulate a PEDOT:PSS hydrogel with the right rheology for DIW. DIW allowed the creation of intricate 3-dimensional shapes that when dried, provided a competitive power factor. Moreover, in wet state, the DIW patterns are flexible, and when combined with a stretchable substrate, led to stretchable TE devices that retain conductivity up to 15% strain. This work holds significant promise for the future development of soft …