Non‐Blinking Semiconductor Colloidal Quantum Dots for Biology, Optoelectronics and Quantum Optics

Abstract

Twinkle, twinkle: The blinking of semiconductor colloidal nanocrystals is the main inconvenience of these bright nanoemitters. There are various approaches for obtaining non-blinking nanocrystals, one of which is to grow a thick coat of CdS on the CdSe core (see picture). Applications of this method in the fields of optoelectronic devices, biologic labelling and quantum information processing are discussed.The blinking of semiconductor colloidal nanocrystals is the main inconvenience of these bright nanoemitters. For some years, research on this phenomenon has demonstrated the possibility to progress beyond this problem by suppressing this fluorescence intermittency in various ways. After a brief overview on the microscopic mechanism of blinking, we review the various approaches used to obtain non-blinking nanocrystals and discuss the commitment of this crucial improvement to applications in the fields of optoelectronic devices, biologic labelling and quantum information processing.

Molecular recognition of DNA–protein complexes: A straightforward method combining scanning force and fluorescence microscopy

“…Our data support the idea that the quantum yield reported for the particles is proportional to the non-dark fraction. Recently, the generation of non-blinking Qdots that would overcome this limitation has been reported [29]. Other fluorophores and defined molecular complexes such as Alexa dye coupled proteins with known stoichiometry will have to be analyzed to determine if the surface and imaging conditions in general influence the efficiency of detecting fluorescent molecules.…”

Einzelmoleküle als optische Nanosonden für weiche und komplexe Materie

“…112, 113 Dagegen findet man es weder in geordneten molekularen Kristallen114 noch in Diamanten,115 bei durch Selbstorganisation entstandenen Punkten heteroepitaxialer Strukturen116, 117 oder in Nanokristallen mit genügend dicker Schale 118. 119 Wenn das einschließende Potential “weich” ist, treten Auger‐Prozesse seltener auf, und der geladene Kristall kann weiter fluoreszieren 120. Blinken scheint daher in enger Beziehung zur Umgebungsstruktur zu stehen und könnte deshalb zu deren Untersuchung genutzt werden.…”

Single Molecules as Optical Nanoprobes for Soft and Complex Matter

“…112, 113 It is not observed in ordered molecular crystals,114 nor in diamond,115 nor for the self‐assembled dots of heteroepitaxial structures,116, 117 nor in nanocrystals when their shell is thick enough 118. 119 When the confinement potential is soft, Auger processes are reduced and the charged crystal still fluoresces 120. Blinking therefore appears to be intimately connected to the structure of the environment, and therefore could be exploited to probe it.…”