Preparation and self-assembled behaviors of OPPEA and A-BPEF composite Langmuir-Blodgett films with photovoltaic conversion and acid-base gas sensing properties

The composite Langmuir-Blodgett films of organic photovoltaic materials demonstrate unique advantages in the fields of photovoltaic devices, sensing, and chiral optics by fusing the functionality of organic materials with the orderliness of LB technology through precise assembly at the molecular scale. In this study, composite LB films of o-phenylphenoxyethyl acrylate (OPPEA) and bis-etherfluorene acrylate (A-BPEF) with Congo red (CR), methylene blue (MB), rhodamine B (RhB), and Saffron T (ST) dyes, respectively, have been successfully prepared by LB technology. The microstructure and optical properties of the composite films were systematically characterized by means of surface pressure-area isotherms (π-A curves), atomic force microscopy (AFM), transmission electron microscopy (TEM), contact angle measurements, and UV–visible spectroscopy, and the acid-base gas response and photoelectric conversion properties were investigated. The results show that different dye subphases significantly affect the molecular arrangement and microscopic morphology of the composite films, and the OPPEA/CR and A-BPEF/CR composite films exhibit significant response to HCl and NH 3 gases, while the OPPEA/RhB and A-BPEF/ST composite films show excellent photoelectric conversion efficiency and stability. This study provides a theoretical basis for the design and application of high-performance organic photovoltaic materials.