Brice Le Borgne

Conformal Electronics Wrapped Around Daily Life Objects Using an Original Method: Water Transfer Printing

The water transfer printing method is used to transfer patterned films on random three-dimensional objects. This industrially viable technology has been demonstrated to intimately wrap metallic and polymeric films around different materials. This method avoids the use of rigid substrate during the transfer step. Patterns can be transferred to objects without folds even when holed, addressing a challenging issue in the field of conformal electronics. This technique allows high film bending properties to be reached. This promising method enables us to integrate large-area films onto daily life objects. A bent capacitive touchpad is fabricated showing the potential applications of this technology.

Spreading and drying impact on printed pattern accuracy due to phase separation of a colloidal ink

AbstractDrop-on-demand inkjet printing relies on the dispensing and precise positioning of very small amount of liquid on substrate before its transformation to a solid. Consequently, many steps are involved during inkjet printing process that must be understood to fabricate accurate patterns. In this work, multicomponent colloidal mixture spreading and drying is investigated. A systematic study has been performed to explain the impact of the jetting frequency, the drop spacing, and the substrate exposure to UV ozone on a colloidal silver ink behavior. It is demonstrated that phase separation between stabilizing agent and colloids can occur during the spreading step. This phenomenon is described and appears to be related to the colloidal nature of the ink. It is shown that it can have a negative impact on pattern accuracy and several routes are given to overcome these issues. Graphical abstractImpact of printing velocity and substrate wetting on patterns accuracy due to ink phase separation

The Use of a Water Soluble Flexible Substrate to Embed Electronics in Additively Manufactured Objects: From Tattoo to Water Transfer Printed Electronics

The integration of electronics into the process flow of the additive manufacturing of 3D objects is demonstrated using water soluble films as a temporary flexible substrate. Three process variants are detailed to evaluate their capabilities to meet the additive manufacturing requirements. One of them, called water transfer printing, shows the best ability to fabricate electronics onto 3D additively manufactured objects. Moreover, a curved capacitive touchpad hidden by color films is successfully transferred onto the 3D objects, showing a potential application of this technology to fabricate fully additively manufactured discrete or even hidden electronic devices.

(Invited) Dual-Gate TFT for Chemical Detection

Electronic devices have shown their interests to develop chemical and biological sensors based on electrical detection. Various field effect transistor structures applied to those detections exist and can be used in liquids, but have often a limited sensitivity, especially due to the Nernst limit. Dual gate field effect transistor allows to enhance this sensitivity by capacitive amplification. This paper describes the development of a field effect transistor based on polycrystalline silicon. Technological parameters as thicknesses and doping level are studied in order to obtain a good amplification. Polarization conditions are optimized in order to fit the requirements for testing in liquid media. The specific use of polycrystalline silicon as active layer can lead to a high amplification of charges and/or potential levels. A proof of sensing detection is obtain with pH measurement.