Transmuting the blue fluorescence of hekates mesogens derived from tris(N-salicylideneaniline)s core via ZnS/ZnS:Mn2+ semiconductor quantum dots dispersion

Abstract In this paper, we present the preparation of nano-soft composites of ZnS and ZnS:Mn 2+ quantum dots (QDs) with star shaped hekates mesogens (HMs) derived from tris(N-salicylideneaniline) core. The photophysical studies of the neat HMs and it's composites with QDs have been carried out as a function of temperature. The blue emission of HMs is found to be enhanced and red shifted in the presence of ZnS QDs. An induced yellow emission at 575 nm has been observed in HM - ZnS:Mn 2+ QDs composite which is attributed to the 4 T 1 to 6 A 1 transition between the sp electrons of ZnS and d electrons of Mn 2+ in the ZnS:Mn 2+ QDs. The change in photophysical properties of HMs is analogous to the adscititious electron–proton interactions in hydrogen bonded environment after the dispersion of QDs. The large shift in N - H stretching and induction of a new S - H stretching band at 2734 cm − 1 in the composites reveal the occurrence of intermolecular interactions between the HMs and QDs. Moreover, the presence of QDs significantly changes the molecular orientation of the HMs as adduced by polarized optical microscopy. Tunability of the blue emission of HMs due to QDs dispersion depends on the degree of intermolecular interactions in the Guest-Host system. This study depicts its possible applications in the quantum dots based tunable photoluminescent displays.