Large Scale Solution Assembly of Quantum Dot–Gold Nanorod Architectures with Plasmon Enhanced Fluorescence

Tailoring the efficiency of fluorescent emission via plasmon–exciton coupling requires structure control on a nanometer length scale using a high-yield fabrication route not achievable with current lithographic techniques. These systems can be fabricated using a bottom-up approach if problems of colloidal stability and low yield can be addressed. We report progress on this pathway with the assembly of quantum dots (emitter) on gold nanorods (plasmonic units) with precisely controlled spacing, quantum dot/nanorod ratio, and long-term colloidal stability, which enables the purification and encapsulation of the assembled architecture in a protective silica shell. Overall, such controllability with nanometer precision allows one to synthesize stable, complex architectures at large volume in a rational and controllable manner. The assembled architectures demonstrate photoluminescent enhancement (5×) useful for applications ranging from biological sensing to advanced optical communication.通过等离激元-激子耦合（plasmon–exciton coupling）调控荧光发射效率，需在纳米尺度实现结构精准控制，且需采用当前光刻技术无法实现的高产率制备路径。若能解决胶体稳定性与低产率问题，此类体系可通过自下而上方法（bottom-up approach）制备。本研究报道了该研究路径的进展：将量子点（quantum dots，发射体）组装于金纳米棒（gold nanorods，等离激元单元）之上，实现了间距、量子点与纳米棒比例的精准调控，同时具备长期胶体稳定性，由此可将组装得到的结构进行纯化，并包封于保护性二氧化硅壳层中。总体而言，这种纳米级精度的可控性，使得我们能够以理性、可控的方式大规模合成稳定的复杂结构。该组装结构展现出5倍的光致发光增强效果，可应用于从生物传感至先进光通信等诸多领域。