Fig. 5: Single-particle and ensemble measurements of biexciton properties.

a Second-order photon correlation curves with fittings (black solid lines) of single monomer (gray), homodimer with 7.8 nm core-spacing (diatomic molecule, red), homodimer with 11.4 nm core-spacing (double-QD, black). The g⁽²⁾ contrast (g₀²) is calculated as a ratio between the g⁽²⁾ values at t = 0 ns versus t = 1000 ns. b Transient PL spectra of the diatomic molecules under different excitation power measured by the micro-liquid film approach. Inset: Difference in transient PL spectra between <N > = 1.0 and 0.1 (orange), and between <N > = 3.0 and 1.0 (blue). c Pump-power dependence of PL intensity for total PL (red), Auger-free emission (straight dotted line), single-exciton (gray), and two bi-exciton channels (blue and orange) of the diatomic molecules. Dashed black lines are the fits to the ‘PL saturation’ model. d Pump-power dependence of normalized PL spectra for the diatomic molecules measured by the micro-liquid film approach. e–g The configurations of the band-edge electron (green and gray) and hole (red) wavefunctions of single-exciton and two biexciton states for a diatomic molecule. Source data are provided as a Source Data file.