Confinement and antenna effect for ultrasmall Y₂O₃:Eu³⁺ nanocrystals supported by MOF with enhanced near-UV light absorption thereby enhanced luminescence and excellently multifunctional applications

A novel host-guest luminous system with enhanced near-UV light absorption thereby enhanced luminescence are designed based on the synergism of quantum confinement, spatial confinement, and antenna effect, where ultrasmall Y₂O₃:Eu³⁺ nanocrystals are fixed inside MOF (Eu/Y-BTC) as supporting structure. The Eu/Y-BTC not only limits the size and leads to lattice distortion of Y₂O₃:Eu³⁺ nanocrystals and controls the distance between nanocrystals, but also promotes the light absorption and emission. The significantly red-shifted and broadened charge transfer band of Y₂O₃:Eu³⁺/(Eu/Y-BTC) leads to the excellent applications of Y₂O₃:Eu³⁺ in white light-emitting diodes (LEDs). Our results show that white light with superior color quality (CRI>90) and extremely high luminous efficacy (an LER of 335 lm/W) could be achieved using Y₂O₃:Eu³⁺/(Eu/Y-BTC) as red phosphor. The Y₂O₃:Eu³⁺/ (Eu/Y-BTC) also improves the photoelectric performance of dye-sensitized solar cells (DSSCs), not only because Y₂O₃:Eu³⁺/(Eu/Y-BTC) has a large specific surface area and the adsorption amount of the dye is increased, but also because the valence band position of Y₂O₃:Eu³⁺/(Eu/Y-BTC) is 2.41 eV, which can provide an additional energy level between the TiO₂ and dye, promoting electron transfer. For these advantageous features, the multifunctional Y₂O₃:Eu³⁺/(Eu/Y-BTC) composite product will open new avenues in white LEDs and DSSCs.