Organic Lasers Harnessing Excited State Intramolecular Proton Transfer Process

Excited state intramolecular proton transfer (ESIPT) molecules are considered to be natural born laser materials because of their intrinsic four-level system. Organic lasers based on ESIPT materials, especially recently developed micro/nanolasers, have been drawing great attention in the past few decades due to their unique photophysical properties, such as ultralow threshold and high-quality value, as well as near-infrared (NIR) and wavelength tunable emission. These photophysical properties facilitate their widespread applications in lasing communication, ultrasensitive sensing, biological imaging, data storage and on-chip optical circuits. In this Review, first, the ESIPT process is introduced concisely. Second, recent advances of ESIPT-based organic lasers in solution, film and crystal states are reviewed. Finally, the current challenges and future development of ESIPT-based organic lasers are presented.