Trotsiuk Liudmila, Muravitskaya Alina, Movsesyan Artur, Ramanenka Andrei, Prudnikau Anatol, Antanovich Artsiom, Lesnyak Vladimir, Gaponenko Sergey V, Govorov Alexander O
B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk 220072, Belarus.
Department of Physics and Mathematics, University of Hull, Cotthingham Road, HU6 7RX Hull, U.K.
Nano Lett. 2023 Sep 27;23(18):8524-8531. doi: 10.1021/acs.nanolett.3c02250. Epub 2023 Sep 13.
Metal-enhanced photoluminescence is able to provide a robust signal even from a single emitter and is promising in applications in biosensors and optoelectronic devices. However, its realization with semiconductor nanocrystals (e.g., quantum dots, QDs) is not always straightforward due to the hidden and not fully described interactions between plasmonic nanoparticles and an emitter. Here, we demonstrate nonclassical enhancement (i.e., not a conventional electromagnetic mechanism) of the QD photoluminescence at nonplasmonic conditions and correlate it with the charge exchange processes in the system, particularly with high efficiency of the hot-hole generation in gold nanoparticles and the possibility of their transfer to QDs. The hole injection returns a QD from a charged nonemitting state caused by hole trapping by surface and/or interfacial traps into an uncharged emitting state, which leads to an increased photoluminescence intensity. These results open new insights into metal-enhanced photoluminescence, showing the importance of the QD surface states in this process.
