Thermotropic liquid crystalline and fluorescence resonance energy transfer under temperature excitation of imidazolium salt/CdTe quantum dots composites

The optical characteristics and surface area of quantum dots (QDs) render them a compelling platform for the development of composite materials based on fluorescence resonance energy transfer (FRET). A novel luminescent liquid crystal nanocomposite (CBphCM-CdTe) has been successfully prepared through the ionic self-assembly route using imidazolium salt (CBphCM) and CdTe QDs. DSC and POM analyses confirm that CBphCM-CdTe undergoes the smectic A and C phases, but its liquid crystal temperature range is narrower compared to that of pure CBphCM. Concurrently, CBphCM-CdTe exhibits excellent fluorescence characteristics. Increasing temperature serves as a trigger for fluorescence resonance energy transfer between CdTe QDs and CBphCM, wherein the fluorescence of CdTe QDs is quenched, while the fluorescence intensity of CBphCM increases with rising temperature. A strong correlation exists between temperature and fluorescence intensity within the liquid crystal temperature range. Such thermochromic materials are anticipated to facilitate innovative development in dynamic thermo-optical sensing, thereby enabling enhanced control over light manipulation in stimuli-responsive devices.