Ap. Desilva et al., DIRECT VISUAL INDICATION OF PH WINDOWS - OFF-ON-OFF FLUORESCENT PET (PHOTOINDUCED ELECTRON-TRANSFER) SENSORS SWITCHES, Chemical communications, (21), 1996, pp. 2399-2400
1-3, which contain a fluorophore and two proton receptors with opposit
e PET (photoinduced electron transfer) characteristics, only display s
trong fluorescence within a pH window whose position and width are tun
able.