Dual-Mode Amplification of Circularly Polarized Luminescence in DNA Complex Films via Stretching and Photoirradiation

There is a growing interest in film-based circularly polarized luminescent (CPL) materials for applications in optoelectronic devices, information storage, and optical biosensors. Here, we report on the dual stretchable and photoswitchable CPL active DNA films, achieved by integrating DNA with cationic surfactants and organic dyes. The formed DNA-CTAB complex film can serve as a stretchable and chiral scaffold, transferring its chirality to achiral dye molecules. When achiral dyes are doped into the film, weak CPL is detected. Upon stretching the film, the CPL signal is significantly amplified up to 150-fold. Moreover, when photoactive spiropyran (SP) is doped, CPL can be switched by alternative ultraviolet and visible light irradiation. The CPL signal can be further regulated and synergistically amplified in a film by simultaneously doping SP and a donor dye through photoirradiation modulated energy transfer. These stretchable and photoswitchable films offer an approach to broaden the scope of chiroptical materials.