Light‐Stimulated Luminescence Control of Lead Halide‐Based Perovskite Nanocrystals Coupled with Photochromic Molecules via Electron and Energy Transfer

Abstract

Photoswitchable nanomaterials are key materials in the development of advanced imaging techniques, such as super‐resolution fluorescence microscopy. The combination of perovskite CsPbBr3 nanocrystals (NCs) with bright photoluminescence (PL) emission and diarylethenes (DAEs) with structural changes in response to ultraviolet (UV) and visible light is a promising candidate system. Herein, CsPbBr3 NCs are coupled with photochromic DAE molecules to control the PL emission from the NCs by light stimulation. The PL emission is successfully switched ON and OFF by alternating UV and visible light irradiation. Time‐resolved PL emission studies suggest that Förster resonance energy transfer from CsPbBr3 NCs to the closed‐ring form of DAE occurs after UV irradiation, and the PL emission is quenched. Upon visible‐light irradiation, DAE is converted to the open‐ring isomer, and the PL emission is restored. Femtosecond pump‐probe spectroscopy reveals that light stimulation induces not only energy transfer but also photoinduced electron transfer in the NC‐DAE pair on the picosecond timescale to form DAE radicals. Thus, it is suggested that the holes residing in the NCs react with the NCs, degrading the PL emission. Stable PL switching is realized using 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) as a hole scavenger to avoid the reaction between the holes and NCs.

Photoswitching the fluorescence of nanoparticles for advanced optical applications

“…2B). 47 In this work, it has been demonstrated that alterations in the moieties of diarylethene affect the interactions with nanocrystals, thus inuencing the photoswitching ratio of PF NPs. In addition to the direct surface-assembly method, a coating layer on the surface of NPs can also facilitate the selfassembly of photochromic components (Fig.…”

“…2A, the direct surface assembly method involves the anchoring of the photochromic component onto the NP surface. 47,51 As an example, Akaishi et al coupled uorescent perovskite nanocrystals with photochromic diarylethene for achieving a photoswitching of uorescence from perovskite nanocrystals (Fig. 2B).…”

Photochromic diarylethene induced fluorescence switching materials constructed by non-covalent interactions

“…4a). 43 CsPbBr 3 nanocrystals at about 10.8 nm exhibited green fluorescence with an emission wavelength of 512 nm (Fig. 4b and c).…”

“…1). 36,[42][43][44][45][46][47][48] In 2017, Liu and colleagues synthesized a cationic photochromic diarylethene with symmetrically grafted dialkylammonium (compound 1 in Fig. 1) and a [Ru(bpy) 3 ] 2+ complex containing two dibenzo-24-crown-8 (DB24C8) units (Fig.…”

Ligand-protected nanocluster-mediated photoswitchable fluorescent nanoprobes towards dual-color cellular imaging

“…[26][27][28][29][30] In particular, surface ligand layers of inorganic NPs can act as effective mediators to regulate the interactions between the inorganic core and photochromic dyes, which make them attractive in modulating the microenvironment of photochromic dyes on the surface of these NPs. So far, a variety of nanoparticles have been used to construct photocontrolled uorescence switches, such as semiconductor quantum dots, 31 upconverting NPs, 32 perovskite nanocrystals 33 and metal nanoclusters. 34 However, multi-color uorescence photoswitches based on ligand-protected NPs have rarely been achieved, [34][35][36] and the distinct capability of NPs for modulating the photophysical properties of photochromic dyes has not been adequately exploited.…”