Strain–Microstructure–Optoelectronic Inter-Relationship toward Engineering Mechano-Optoelectronic Conjugated Polymer Thin Films

Mechano-optoelectronic (MO) behavior indicates changes in optoelectronic properties in response to the applied mechanical deformation. The MO behavior can be employed to monitor the mechanical deformation of a targeted system by tracing its optoelectronic properties. Poly(3-hexylthiophene) and phenyl-C(61)-butyric acid methyl ester (P3HT/PCBM) blend thin films exhibited changes in direct current under tensile strain. Although optoelectronic properties and photovoltaic performance of P3HT/PCBM blends have been studied extensively and intensively, research required for MO properties has a fundamental difference from previous research mostly for solar cells. In research for MO systems, a greater extent of changes in optoelectronic properties under mechanical deformation is favorable. Herein, previous research for optoelectronic properties and mechanical properties of conjugated polymers will be reviewed from a perspective on MO properties. The microstructure of a conjugated polymer thin film plays a pivotal role in its optoelectronic properties and mechanical properties. Key parameters involved in the microstructure of conjugated polymer thin films will be addressed. A scalable process is required to broaden applications of MO systems. Potential challenges in the fabrication of MO conjugated polymer thin films will be discussed. Finally, this review is envisioned to provide insight into the design and manufacturing of MO conjugated polymer thin films.