Nanoscale assembly of ultrasmall metal nanoclusters (MNCs) by means of molecular forces has proven to be a powerful strategy to engineer their molecule-like properties in multiscale dimensions. By leveraging depletion attraction as the guiding force, herein, we demonstrate the formation of kinetically trapped NCs assemblies with enhanced photoluminescence (PL) and excited state lifetimes and extend the principle to cluster impregnated cationic nanogels, nonluminescent Au(I)−thiolate complexes, and weakly luminescent CuNCs. We further demonstrate a thermal energy driven kinetic barrier breaking process to isolate these assemblies. These isolated assemblies are thermodynamically stable, built from a strong network among several discrete, ultrasmall AuNCs and exhibit several unusual properties such as high stability in various pH, strong PL, microsecond lifetimes, large Stocks shifts, and higher accumulation in the lysosome of cancer cells. We anticipate our strategy may find wider use in creating a large variety of MNC-based assemblies with many unforeseen arrangements, properties, and applications.
The development of technologies to convert solar energy and store it into a usable form of energy at a massive scale is a major thrust of research worldwide. Therefore, suitable energy storage options/devices are being sought after to store electrical energy generated by solar cells through harvesting solar radiation. The integration of solar energy converting device with supercapacitors (SCs) as a single device-called as photosupercapacitor, has great potential to power wearable and portable electronics. This dual functioning device stores the harvested energy electrochemically to provide an alternative source of power, may address the pressing issues for storage of the generated electrical energy. Different configurations to integrate solar cells and storage devices are being explored, and the integration of solar cells, particularly third-generation, with SCs can provide high-power conversion efficiencies. Nonetheless, the exploration of flexible electronics to meet the demand for wearable devices that operate continuously without an external power supply is highly desired. In this article, we have thoroughly discussed the developments of integrated devices based on third-generation planar and flexible solar devices, which include: dye-sensitized, quantum dot sensitized, organic, perovskite using SCs as energy-storage devices. Besides, the emphasis is also given on integrated flexible or wearable systems as self-charging and self-powered integrated systems. The present perplexing issues and their research perspectives are also elaborated to stimulate the advancement of such integrated devices in the upcoming years.
Although quantum dots (QDs) are perceived to be similar
to fluorescent
organic dyes, the underlying mechanism behind their photophysical
response in the presence of analytes may not necessarily follow the
path usually taken by molecular dyes. With the aim to understand how
the exciton dynamics of QDs proceeds in the presence of chemical analytes,
a thorough spectroscopic investigation of less-toxic zinc–silver–indium
sulfide (ZAIS) QDs in the presence of selected naphthoquinone derivatives
(analytes) has been undertaken in an aqueous medium. Specifically,
the charge carrier recombination dynamics of ZAIS has been probed
in the presence of chosen analytes by systematically varying the chemical
functionalities attached to these analytes. The absorbance, fluorescence,
and transient absorption measurements infer that fluorescence quenching
of ZAIS in the presence of analytes proceeds through a very different
pathway from that usually observed for molecular dye analyte systems.
This observation has been rationalized by considering the presence
of active surface of QDs and subsequent changes in their surface dynamics
in the presence of analytes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.