Towards 3D-printed organic electronics: Planarization and spray-deposition of functional layers onto 3D-printed objects

The last years have seen a surge in the interest for "smart objects" obtained with the integration of electronics and custom designed structures. One of the possible approaches for the fabrication of such devices is 3D printing supporting elements and attach to them discrete electronic components. Opposed to this approach, we demonstrate the facile integration of conformal organic electronics devices in 3D printed structures, where the device is directly fabricated on or in the printed object. To obtain cost-effective and easy-to-scale devices, the substrates are fabricated via a Fused Deposition Modeling (FDM) procedure which leads to inherently rough layers. In order to enable the fabrication of functional layers few hundreds of nm thick, we develop a process, based on spray-deposition, for the planarization of the structure and the in situ deposition a functional layer. The realization of conductive and semi-transparent CNTs, AgNW and PEDOT:PSS thin films on a 3D-printed substrate is demonstrated and the films are characterized in terms of transmittance and sheet resistance. The technique is finally applied for the realization of a semi-transparent heating chamber with an arbitrary shape with potential applications in the field of bioelectronics and consumer applications. (C) 2016 Elsevier B.V. All rights reserved.