Julianna Panidi

Solution‐processed high‐performing ambipolar organic phototransistors (OPTs) can enable low‐cost integrated circuits. Here, we demonstrate a heteroatom engineering approach to modify the electron affinity of a low band gap diketopyrrolopyrole (DPP) co‐polymer, resulting in well‐balanced charge transport, a more preferential edge‐on orientation and higher crystallinity. Changing the comonomer heteroatom from sulfur (benzothiadiazole (BT)) to oxygen (benzooxadiazole (BO)) led to an increased electron affinity and introduced higher ambipolarity. Organic thin film transistors fabricated from the novel PDPP‐BO exhibited charge carrier mobility of 0.6 and 0.3 cm 2 /Vs for electrons and holes, respectively. Due to the high sensitivity of the PDPP‐based material and the balanced transport in PDPP‐BO, we present its application as an NIR detector in the device architecture of organic phototransistors. By maintaining a high on/off ratio (9 × 10 4 ), we show ambipolar OPTs with photoresponsivity of 69 and 99 A/W and specific detectivity of 8 × 10 7 for the p‐type operation and 4 × 10 9 Jones for the n‐type regime. The high symmetric NIR‐ambipolar OPTs were also evaluated as ambipolar photo‐inverters, and showed a 46% gain enhancement under illumination. This article is protected by copyright. All rights reserved

Flexible electronics have seen extensive research over the past years due to their potential stretchability and adaptability to non‐flat surfaces. They are key to realizing low‐power sensors and circuits for wearable electronics and Internet of Things (IoT) applications. Semiconducting metal‐oxides are a prime candidate for implementing flexible electronics as their conformal deposition methods lend themselves to the idiosyncrasies of non‐rigid substrates. They are also a major component for the development of resistive memories (memristors) and as such their monolithic integration with thin film electronics has the potential to lead to novel all‐metal‐oxide devices combining memory and computing on a single node. This review focuses on exploring the recent advances across all these fronts starting from types of suitable substrates and their mechanical properties, different types of fabrication methods for thin film transistors and memristors applicable to flexible substrates (vacuum‐ or solution‐based), applications and comparison with rigid substrates while additionally delving into matters associated with their monolithic integration.