Open AccessTransparent Nanocomposites Comprising Ligand-Exchanged CuInS2/ZnS Quantum Dots and UV-Cured Resin for Wavelength Converters
Author(s) -
Momo Shiraishi,
Yoshiki Iso,
Tetsuhiko Isobe
Publication year - 2022
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.2c02922
Subject(s) - nanocomposite , photoluminescence , materials science , quantum dot , quantum yield , oleylamine , nanocrystal , chemical engineering , photochemistry , nanotechnology , fluorescence , chemistry , optoelectronics , optics , physics , engineering
Quantum dots (QDs) dispersed in UV-curable resin are used for patterning in photolithography and inkjet printing. However, low affinity between the main component of UV-curable resins known as celloxide, an alicyclic diepoxy compound, and QD surface ligands with alkyl chains causes significant aggregation of QDs. In this study, the dispersibility of core/shell CuInS 2 /ZnS QDs with adsorbed 1-dodecanethiol and oleic acid in celloxide was improved using the ligand exchange method to prepare transparent fluorescent nanocomposites. Cyclohexyl 3-mercaptopropionate (MPACH) and 3-mercaptopropionic acid (MPA) were successfully adsorbed onto the QDs. MPACH-modified QDs (QD-MPACH) were well dispersed in the UV-curable resin, whereas MPA-modified QDs (QD-MPA) exhibited significant aggregation. Nanocomposite plates containing dispersed QDs were prepared by UV irradiation. The QD-MPACH nanocomposite plate was transparent, while the QD-MPA nanocomposite plate was turbid. The homogeneous dispersion of QD-MPACH was attributed to the similarity in the molecular structure between MPACH and celloxide. The photoluminescence (PL) peak of the QD-MPA nanocomposite occurred at a longer wavelength than that of the QD-MPACH nanocomposite. Furthermore, compared with the absolute photoluminescence quantum yield (PLQY) of the as-prepared QDs in toluene (55%), that of the QD-MPA nanocomposite was smaller (46%), and that of the QD-MPACH nanocomposite was higher (61%). An enhanced self-absorption effect was observed for the QD-MPA nanocomposite because of significant light scattering by the aggregates and concentration quenching, resulting in the PL redshift and decreased PLQY. Moreover, the PL intensity of the QD-MPACH nanocomposite was maintained at 98% of the initial value after continuous excitation-light irradiation for 5 h. The high PLQY and photostability of the QD-MPACH nanocomposite are beneficial in practical applications.