Advances in Covalent Organic Frameworks as Fluorescent Sensors for pH.

pH value is essential for maintaining ecological balance, and it plays a significant role in atmospheric monitoring, water quality assessment, and biological health. Therefore, it is very important for developing rapid and sensitive pH detection methods. Covalent organic frameworks (COFs) have emerged as promising fluorescent sensing materials due to their tunable organic structures, high thermal stability, and large specific surface area, making them ideal for pH detection in both environmental and biological samples. This review examines various types of COF fluorescence sensors and discusses their sensing mechanisms and provides the theoretical foundation for the development of more excellent pH fluorescence sensors.