Modulation of excited state proton transfer

The mechanism of excited state proton transfer (ESPT) has been widely investigated in various fields, owing to its fundamental role in many systems. The ability to regulate the ESPT process has enabled the range of its applications to be greatly expanded, and the corresponding investigative work has become increasingly sophisticated. In particular, the unmeasurable quantities at a molecular level are of great interest. As modulation technology forms the foundation of many applications of ESPT, its development is worthy of further exploration and discussion. In this article, we summarize recent approaches to ESPT regulation, including the use of solvent polarity, electric fields, and solvent medium. We also consider the mechanisms of ESPT and related applications, and discuss the debate over whether a stepwise or concerted process occurs in systems of excited state double proton transfer. Finally, we summarize the challenges of ESPT research and present some ideas that may guide future progress.