QYs were calculated according to the following equation, using standard references including perylene monoimide (emission peak at 560 nm, QY = 50 % in methanol), Oxazine 170 (emission peak at 640 nm, QY = 20 % in methanol), or Cy5.5 (emission peak at 707 nm, QY = 20 % in DMSO) QYS ¼ QYR ðIS=IRÞ ðAR=ASÞ ðnS=nRÞ2; where QYS and QYR are the QYs of sample and a standard reference, respectively; IS and IR are the integrations of fluorescence emissions of sample and a standard reference, respectively; AS and AR are the corresponding absorbance of sample and a standard reference, respectively; and nS and nR are the refractive indices of the corresponding solvents.