Luminescence Color Tuning by Regulating Electrostatic Interaction in Light-Emitting Devices and Two-Photon Excited Information Decryption

It is well-known that the variation of noncovalent interactions of luminophores, such as π–π interaction, metal-to-metal interaction, and hydrogen-bonding interaction, can regulate their emission colors. Electrostatic interaction is also an important noncovalent interaction. However, very few examples of luminescence color tuning induced by electrostatic interaction were reported. Herein, a series of Zn­(II)-bis­(terpyridine) complexes (<b>Zn-AcO</b>, <b>Zn-BF</b>_<b>4</b>, <b>Zn-ClO</b>_<b>4</b>, and <b>Zn-PF</b>_<b>6</b>) containing different anionic counterions were reported, which exhibit counterion-dependent emission colors from green-yellow to orange-red (549 to 622 nm) in CH₂Cl₂ solution. More importantly, it was found that the excited states of these Zn­(II) complexes can be regulated by changing the electrostatic interaction between Zn²⁺ and counterions. On the basis of this controllable excited state, white light emission has been achieved by a single molecule, and a white light-emitting device has been fabricated. Moreover, a novel type of data decryption system with <b>Zn-PF</b>_<b>6</b> as the optical recording medium has been developed by the two-photon excitation technique. Our results suggest that rationally controlled excited states of these Zn­(II) complexes by regulating electrostatic interaction have promising applications in various optoelectronic fields, such as light-emitting devices, information recording, security protection, and so on