Micellular fluorescence resonance energy transfer based fluorescent ratiometric response to hydrocarbon analytes

Fluorescence resonance energy transfer (FRET) has been utilised to develop numerous selective and sensitive fluorescent ratiometric sensors. Typically, FRET-based fluorescent ratiometric sensors rely on chemical interactions between the sensor and analyte to illicit a response, thus unreactive hydrocarbons are a neglected analyte and a source for new sensors. By containing an unbound donor–acceptor system within micelles, energy transfer is enabled by spatial confinement. This offers the potential of a ratiometric response as a hydrocarbon analyte is added. Introducing a hydrocarbon analyte to this system causes micelles to swell, increasing the donor–acceptor distance and thus reducing the amount of observed energy transfer. We present InP/ZnS quantum dot donors interacting with a Nile Red acceptor, confined by cetyltrimethylammonium bromide (CTAB)-based micelles. We alleviated spatial confinement of the pair within micelles using common laboratory solvents to represent hydrocarbons, (toluene, hexane and octadecene). We constructed calibration curves for each solvent and found effective sensing ranges of 0.009–0.21, 0.008–0.27 and 0.003–0.06 M for toluene, hexane and octadecene, respectively. This study contributes towards the development of new hydrocarbon sensors utilising this new mechanism

Towards Artificial Antenna Complexes of Cadmium Selenide Quantum Dots

Climate change has created a demand for a paradigm shift in energy generation methods and sources. New and improving renewable energy technologies form a major part of this upheaval. Specifically, solar energy has high energy potential but is still underutilised due to fundamental limits – only a fraction of the solar spectrum can be efficiently harvested. It is possible to overcome these limits using light management processes. However, these depend on an ordered structure to be effective. To solve a similar problem, nature has developed efficient light harvesting and management structures, from which inspiration can be drawn. Cyanobacterial phycobilisomes are a discrete and ordered arrangement of chromophores which attenuate and direct light through an energy cascade. Copying this structure, an artificial antenna complex can be envisioned. Here, we propose an energy cascade structure composed of linked cadmium selenide quantum dots. Firstly, we synthesised a series of cadmium selenide quantum dots to represent a broad spectral range covering the visible spectrum and fully characterised them using spectroscopy and TEM imaging. Secondly, we designed and synthesised a range of coupling ligands for click reactions to link the quantum dots together and assemble the antenna complex. Thirdly, the attachment behaviour of these ligands to the quantum dots’ surface was investigated. Unfortunately, while the ligands did bind to the quantum dot surface, with time aggregation occurred. Thus, the potential to create a ordered linked antenna structure of quantum dots was lost. However, instead insight into the qualities of a good and bad ligand to functionalise quantum dots with was gained which will add valuable insight to the wider research community.</p