Conducting polymer (CP)-based electrochemical biosensors have gained great attention as such biosensor platforms are easy and cost-effective to fabricate, and provide a direct electrical readout of the presence of biological analytes with high sensitivity and selectivity.

Stretchable electronics has become a focus of interest amongst the academic research and industrial communities due to its potential to enable a wide variety of emerging applications, including wearable displays, energy-storage, skin-mounted sensors and biosensors, human-machine interfaces and soft robotics. To realise these applications, the devices are required to adhere and conform to soft curvilinear surfaces, while be able to bend, compress, stretch and even self-heal, much like the human skin. Organic materials, particularly, conjugated polymers possess a unique molecular structure, which enables their optical, electrical, and electrochemical properties. In fact, one of the main features that make these materials highly suitable for stretchable electronics is the chemically-tunable mechanical properties that allow structural deformation without significantly affecting the electronic function. In this review, we discuss ours and others’ recent attempts in designing and engineering conjugated polymers and their composites to incorporate new mechanical and physical characteristics that are not intrinsic to these organic materials, such as stretchability and self-healing abilities. We discuss such approaches from a molecular design perspective. In particular, the focus is on the molecular parameters, such as material choices, synthetic approaches and molecular interactions that play a crucial role in enabling such new characteristics. Furthermore, we highlight recent progress in their applications and discuss the future prospects of stretchable organic electronics.

Phosphorous doped carbon dots (P-CDs), prepared by a one-step hydrothermal method, show the phenomenon of aggregation induced red shift emission (AIRSE).

The polyaniline/TiO₂ (PANI/TiO₂) composite photocatalysts were prepared by the in situ chemical oxidation of aniline (An) in the presence of TiO₂ particles. For this purpose, photocatalysts with different amounts of PANI polymer were prepared and analysed. Fourier-transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated successful synthesis of the PANI polymer and its conductivity was also determined. The micrographs of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were used to explain the impact of the aniline amount on the aggregation process during the synthesis of the composites. The smallest size of aggregates was obtained for the photocatalysts with 15% of PANI (15PANI/TiO₂) due to the formation of homogenous PANI. The photocatalytic activity of studied PANI/TiO₂ photocatalysts was validated by monitoring the discoloration and mineralization of Reactive Red azo dye (RR45) in wastewater. The 15PANI/TiO₂ sample presented the highest photocatalytic efficiency under ultraviolet A (UVA) irradiation, in comparison to pure TiO₂. This was explained by the formation of uniformly dispersed PANI on the TiO₂ particles, which was responsible for the synergistic PANI-TiO₂ effect.