Efficient Cementing of CH3NH3PbBr3 Nanoparticles to Upconversion Nanoparticles Visualized by Confocal Microscopy

Upconversion-perovskite nanohybrids are prepared by assembling CH3NH3PbBr3 perovskite nanoparticles (PK) with naked NaYF4:Yb3+, Tm3+ nanoparticles (UCn) via an innovative strategy consisting of using cucurbit[7] uril (CB[7]) to anchor the perovskite nanoparticles firmly and closely to the upconversion nanoparticles, thus leading to UCn@PKCB nanohybrids. A commercial multiphoton laser scanning confocal microscope is used to demonstrate the successful assembly. This technique proves to be useful to evaluate luminescence lifetime in the range of several tens of mu s and allows visualization of the extraordinarily efficient nontrivial resonance energy transfer from the upconversion nanoparticle to the perovskite after near-infrared (NIR) excitation of the nanohybrid as well as the homogeneity of the UCn@PKCB sample. The considerable photostability of the perovskite in these nanohybrids is demonstrated by prolonged irradiation of the nanohybrid under UV light as well as under NIR light.