Herein, we report self-assembled reconfigurable plasmonic diastereomers based on DNA nanotechnology. Up to three plasmonic chiral centers were organized by dynamic DNA origami platforms. Meanwhile, each chiral center could be individually controlled to switch between left-handed and right-handed states. Thus, complex and reconfigurable chiral plasmonic diastereomers with eight plasmonic stereoisomers were achieved, driven by programmed DNA reactions. With these plasmonic diastereomers, we demonstrated the existence of strong cross-talk near-field coupling among chiral centers, and the coupling of chiral centers could substantially contribute to the overall CD signals. Our work provides an important bottom-up approach for building complex and dynamic chiral plasmonics and for probing the interactions of plasmonic chiral centers.
Ag2Se quantum dots (QDs) as an effective biological probe in the second near‐infrared window (NIR‐II, 1000–1700 nm) have been widely applied in bioimaging with high tissue penetration depth and high spatiotemporal resolution. However, the ions deficiency and crystal defects caused by the high Ag+ mobility in Ag2Se crystals are mainly responsible for the inefficient photoluminescence (PL) of Ag2Se QDs. Herein, a tailored route is reported to achieve controllable doping of Ag2Se QDs in which Ag is exchanged by Pb via cation exchange (CE), which is unattainable by direct synthetic methods. The Pb‐doped Ag2Se QDs (denoted as Pb:Ag2Se QDs) present fire‐new optical features with significantly enhanced PL intensity of 4.2 folds. Photoelectron spectroscopy confirms that Pb acts as an n‐type dopant for Ag2Se QDs and therefore the electronic impurities provide additional carriers to fill the traps. Moreover, the general validity of this method is demonstrated to convert different sized Ag2Se into Pb:Ag2Se QDs, so that a wide range of NIR‐II PL with high intensity is obtained. The bright NIR‐II emission of Pb:Ag2Se QDs is further successfully performed in lymphatic system mapping.
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