Fig. 5: Size-dependent radiative lifetimes calculation.
From: Non-monotonic size-dependent exciton radiative lifetime in CsPbBr3 nanocrystals
a Calculated size-dependent radiative lifetimes for cubic (teal squares), relaxed (purple triangles) and orthorhombic (gold circles) CsPbI3 nanocrystal structures with corresponding radiative lifetime extrapolations from fits of the exciton energies and oscillator strengths (lines). Only the energies and oscillator strengths of the first six sizes are fitted, and the test points (red ringed points) demonstrate non-monotonicity in the radiative lifetimes and fair agreement with the extrapolated trend. b Size-dependent Boltzmann probabilities of the dark ground state (black), bright triplet states (gold), and high-lying dim states (gray) show depopulation of the emissive triplets in large nanocrystals. c Calculated excitonic states as a function of nanocrystal size plotted for cubic, orthorhombic, and relaxed structures. Here, states within \(3{\kappa }_{B}T\) above the lowest exciton levels are visualized. The color of each state encodes indicates the exciton transition dipole square magnitude (proportional to oscillator strength) in atomic units [a.u.], which increases for the bright excitons with increasing nanocrystal size.
