Today, more disciplines are intercepting each other, giving rise to “cross-disciplinary” research. Technological advancements in material science and device structure and production have paved the way towards development of new classes of multi-purpose sensory devices. Organic phototransistors (OPTs) are photo-activated sensors based on organic field-effect transistors that convert incident light signals into electrical signals. The organic semiconductor (OSC) layer and three-electrode structure of an OPT offer great advantages for light detection compared to conventional photodetectors and photodiodes, due to their signal amplification and noise reduction characteristics. Solution processing of the active layer enables mass production of OPT devices at significantly reduced cost. The chemical structure of OSCs can be modified accordingly to fulfil detection at various wavelengths for different purposes. Organic phototransistors have attracted substantial interest in a variety of fields, namely biomedical, medical diagnostics, healthcare, energy, security, and environmental monitoring. Lightweight and mechanically flexible and wearable OPTs are suitable alternatives not only at clinical levels but also for point-of-care and home-assisted usage. In this review, we aim to explain different types, working mechanism and figures of merit of organic phototransistors and highlight the recent advances from the literature on development and implementation of OPTs for a broad range of research and real-life applications.

In this work, clay minerals such as kaolin particles were embedded within the network of poly(acrylamide) hydrogel (PAAm) using free radical solution polymerization method. Aniline monomer was absorbed in the network of PAAm/Kaolin composite hydrogel and followed using free radical solution polymerization at room temperature. The novel semi-interpenetrating network was comprised of linear polyaniline immersed in PAAm/Kaolin composite. Electrical conductivity of the hydrogels was measured using four-probe technique. The conductivity for the prepared new semi-interpenetrating polymer network (s-IPN) is found to be 1.1 ×10 -4 S.cm -1 . Thus, a new s-IPN composite hydrogel with good conductive properties was prepared.