Light-Triggered Switching of Quantum Dot Photoluminescence through Excited-State Electron Transfer to Surface-Bound Photochromic Molecules

Abstract

This paper describes reversible "on−off" switching of the photoluminescence (PL) intensity of CdSe quantum dots (QDs), mediated by photochromic furylfulgide carboxylate (FFC) molecules chemisorbed to the surfaces of the QDs. Repeated cycles of UV and visible illumination switch the FFC between "closed" and "open" isomers. Reversible switching of the QDs' PL intensity by >80% is enabled by different rates and yields of PL-quenching photoinduced electron transfer (PET) from the QDs to the respective isomers. This difference is consistent with cyclic voltammetry measurements and density functional calculations of the isomers' frontier orbital energies. This work demonstrates fatigue-resistant modulation of the PL of a QD-molecule complex through remote control of PET. Such control potentially enables applications, such as all-optical memory, sensing, and imaging, that benefit from a fast, tunable, and reversible response to light stimuli.

Leveraging Molecular Properties to Tailor Mixed-Dimensional Heterostructures beyond Energy Level Alignment

“…This Perspective has focused on many underexplored areas of molecular tunability in organic–2D heterojunctions, including hybridization and electrostatics, molecular orientation and thin-film morphology, nonfrontier orbitals and defects, excitonic states, spin, and chirality. All of these phenomena can be further tuned and enhanced through structural and/or electronic reconfigurability, which is a rapidly growing field in mixed-dimensional heterojunctions. ,, Because many organic molecules can be driven to undergo conformation changes (e.g., photoisomerization), nearly every molecular feature that was discussed in this Perspective offers the potential to be dynamically altered. Consequently, organic–2D heterojunctions are likely to be of high interest to application areas that rely on reconfigurability, such as nonvolatile memory, neuromorphic computing, and quantum information sciences …”

Photocontrolled reversible modulation of lanthanide luminescence in mesoporous silica nanospheres by photochromic diarylethenes

“…However, the emission band of Eu(DBM) 3 Áphen completely overlapped with the absorption band of CF-BTHFC in the range of 430-700 nm, implying that an efficient FRET process from Eu(DBM) 3 Áphen to CF-BTHFC may occur. [48][49][50] Meanwhile, the other spectral overlap between the excitation band (310-420 nm) of Eu(DBM) 3 Á phen and the absorption band (340-420 nm) of CF-BTHFC can also lead to quenching of the luminescence of Eu 3+ ions (Fig. 3b).…”

Optical Dynamics of Copper-Doped Cadmium Sulfide (CdS) and Zinc Sulfide (ZnS) Quantum-Dots Core/Shell Nanocrystals

“…The photoluminescence properties of QDs can be tuned accurately with sharp emission depending on their composition and size [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Furthermore, single QDs have a high surface-to-volume ratio catering to a significant number of surface trap states, which then act as de-excitation (non-radiative) centers for photo-generated charge carriers.…”