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Thin‐film transistor circuits on flexible substrates hold major promise for next‐generation human–machine interface systems. However, a major bottleneck is the reliability of the interconnect, which is prone to open‐circuit faults due to mechanical, electrical, and environmental stresses. Here, self‐healing interconnects in thin‐film transistor circuits are demonstrated on flexible substrates resulting in the restoration of >99% of the prefault current. The active material for self‐healing is a dispersion of conductive particles in an insulating fluid that is contained over the interconnect. Healing is triggered by the electric field that appears in the open gap during the occurrence of the fault. The engineering of the active material is discussed; self‐healing circuits are demonstrated and analyzed; and methods to package and integrate the self‐healing feature are discussed with the process flow. This work sets a new benchmark for reliable inkjet‐printed thin‐film transistor circuits on flexible substrates.

Open circuit faults in electronic systems are a common failure mechanism, particularly in large area electronic systems such as display and image sensor arrays, flexible electronics and wearable electronics. To address this problem several methods to self heal open faults in real time have been investigated. One approach of interest to this work is the electric field assisted self-healing (eFASH) of open faults. eFASH uses a low concentration dispersion of conductive particles in an insulating fluid that is packaged over the interconnect. The electric field appearing in the open fault in a current carrying interconnect polarizes the conductive particles and chains them up to create a heal. This work studies the impact of dispersion concentration on the heal time, heal impedance and cross-talk when eFASH is used for self-healing. Theoretical predictions are supported by experimental evidence and an optimum dispersion concentration for effective self-healing is identified.

In order to build flexible electronic systems that can bend in two directions simultaneously, it is required that the substrate be able to stretch easily. This is achieved by the use of elastomeric substrates. Stretchable and bendable electronics reduces the reliability of the interconnect. Factors such as stretching, electrostatic discharge, interaction with the environment etc. increases the chance of interconnect failure due to open circuit faults. This paper describes a mechanism of self-healing open circuit faults by the use of a dispersion of conductive particles in an insulating fluid. Faults are typically repaired in 10s with the heal having a resistance of 10 Ohm-1000 Ohm. The paper provides an overview and the operational limits that determine the feasibility of using the technique to improve interconnect reliability in flexible electronics.

Electronic systems used in space technology applications experience harsh environments, resulting in several failures among which open circuit faults are one. In this work, we investigate self-healing circuits to automatically respond to and repair open circuit failures in electronic systems. The active material is a dispersion of metallic particles in an insulating fluid, and the mechanism of healing is triggered by the electric field appearing in the fault. Specifically, this work discusses the physics of self-healing and investigates the compatibility of the mechanism to high vibration (1–16 g) as well as thermovacuum conditions (5 × 10–5 Torr and −40–125 °C). In conclusion, we demonstrate that the electric field assisted self-healing mechanism is feasible for space technology applications.