Recent advances in soft electronic materials for intrinsically stretchable optoelectronic systems

In recent years, significant progress has been achieved in the design and fabrication of stretchable optoelectronic devices. In general, stretchability has been achieved through geometrical modifications of device components, such as with serpentine interconnects or buckled substrates. However, the local stiffness of individual pixels and the limited pixel density of the array have impeded further advancements in stretchable optoelectronics. Therefore, intrinsically stretchable optoelectronics have been proposed as an alternative approach. Herein, we review the recent advances in soft electronic materials for application in intrinsically stretchable optoelectronic devices. First, we introduce various intrinsically stretchable electronic materials, comprised of electronic fillers, elastomers, and surfactants, and exemplify different intrinsically stretchable conducting and semiconducting composites. We also describe the processing methods used to fabricate the electrodes, interconnections, charge transport layers, and optically active layers used in intrinsically stretchable optoelectronic devices. Subsequently, we review representative examples of intrinsically stretchable optoelectronic devices, including light-emitting capacitors, light-emitting diodes, photodetectors, and photovoltaics. Finally, we briefly discuss intrinsically stretchable integrated optoelectronic systems.