Reversibly electroswitched quantum dot luminescence in aqueous solution.

In this study, we fabricated a novel hybrid film system, in which reversible electroswitching quantum dot (QD) luminescence was realized in aqueous solution for the first time. On the basis of an electrochromic material, poly(methylene blue) (PMB), QD luminescence could be switched effectively in a narrow potential range of -0.4 to 0 V via the corresponding luminescence quenching effect. The luminescence switching operation was reversible and reproducible, and no noticeable changes in both "on" and "off" luminescence intensities were observed in 20 cycles. This simple system not only effectively overcame the harsh operation environment that generally existed in previous reports but also provided an easy method for the design and fabrication of other novel QD electroswitchable hybrid components.