Periodic Fluorescence Variations of CdSe Quantum Dots Coupled to Aryleneethynylenes with Aggregation-Induced Emission

Abstract

CdSe nanocrystals and aggregates of an aryleneethynylene derivative are assembled into a hybrid thin film with dual fluorescence from both fluorophores. Under continuous excitation, the nanocrystals and the molecules exhibit anti-correlated fluorescence intensity variations, which become periodic at low temperature. We attribute this to a structure-dependent aggregation induced emission of the aryleneethynylene derivative, which impacts the rate of excitation energy transfer between the molecules and nanocrystals. Energy transfer also affects the electric transport properties of the hybrid material under optical excitation. This work highlights that combining semiconductor nanocrystals with molecular aggregates, which exhibit aggregation induced emission, can result in unprecedented emerging optical properties.

Porphyrin Functionalization of CsPbBrI2/SiO2 Core–Shell Nanocrystals Enhances the Stability and Efficiency in Electroluminescent Devices

“…This has previously been shown on well‐characterized nanoparticle systems and is providing the foundation of the present work, which focuses on the enhancement of the optoelectronic properties by exchanging the native ligand shell with porphyrin‐based ligands. [ 3–6 ] In the case of perovskite nanocrystals, a ligand exchange is inherently difficult due to the instability of the particles against polar environments. However, it holds the potential of improving crucial parameters such as conductivity, stability, and device efficiency.…”

Short-range organization and photophysical properties of CdSe quantum dots coupled with aryleneethynylenes

“…The synthesis of the CdSe QDs with a diameter of ∼5.4 nm dispersed in hexane and stabilized by hexadecylamine, trioctylphosphineoxide (TOPO) and oleic acid (CdSe/nat) is described in [12] and is based on [14]. The ligand-exchange procedure yielding iodide stabilized QDs (CdSe/I − ) in n-methylformamide (NMF) as well as the synthesis of the sodium 2,2′,2″,2‴,2⁗,2⁗′,2⁗″,2⁗‴-(((benzene-1,2,4,5-tetrayltetrakis(ethyne-2,1-diyl))tetrakis(benzene-4,1-diyl))tetrakis (azanetriyl))octaacetate (AE 1, see figure 1) are also described therein [12,14].…”

“…To demonstrate their presence and clarify the nature of organic linkers in coupled organic-inorganic systems, Raman spectroscopy or infrared vibrational spectroscopy are widely used in the literature [12,16,17]. FTIR spectra of the samples investigated in this study are shown in figure 2(a).…”

“…With this study, we aim to contribute to the understanding of the organic-inorganic interface and provide compelling evidence of direct binding of carboxylate groups of aryleneethynylene (AE) derivatives to CdSe QDs. We chose these promising systems due to the reported fluorescence variations and the suggested energy transfer in hybrid films of sodium 2,2′,2″,2‴,2⁗,2⁗′,2⁗″,2⁗‴-(((benzene-1,2,4,5-tetrayltetrakis(ethyne-2,1-diyl))tetrakis(benzene-4,1diyl))tetrakis(azanetriyl))octaacetate (AE 1, see figure 1) and CdSe QDs in [12]. A comparison to samples containing sodium 2, 2′,2″,2‴-((((2,5-bis((E)-4-methoxystyryl)-1,4phenylene)bis(ethyne-2,1-diyl))-bis(4,1-phenylene))-(azanetriyl))tetraacetate (AE 2, see figure 1) and CdSe QDs allows us to analyze the impact of different substitutions, resulting in a changed number of carboxylate groups and changed electronic properties while keeping the structure similar.…”

Aggregation‐Induced Emission‐Based Platforms for the Treatment of Bacteria, Fungi, and Viruses

“…Since the exciting aggregation‐induced emission (AIE) phenomenon was discovered by Prof. Tang in 2001, [ 8 ] AIE has been considered as a frontier research topic in the fluorescence field over the last two decades. [ 9–15 ] “AIE” was selected as one of the “Top Ten Emerging Technologies in Chemistry” by International Union of Pure and Applied Chemistry. It is interesting to know that the AIE luminogens (AIEgens) can not only be used as diagnostic bioprobes, but also be regarded as therapeutic agents in some cases.…”