pH sensitivity regulation based on photoinduced electron transfer and steric hindrance effect

In this work, the photoinduced electron transfer was used as a principle to prepare a series of fiber-optic pH sensors, and the reference sensor was prepared by modifying the functional group and adjusting the film-forming matrix to alter steric hindrance. The pH indicator's sensitivity has been regulated. The surface of the optical fiber was chemically modified with the pH indicator via chemical bonding to enhance the performance of sensor 5. Sensors 5 and 4 formed the ratiometric pH sensor. The experimental results indicated that pH sensitivity can be regulated, and the manufactured sensors are promising for pH detection.