Fig. 2.

Thickness-dependent EQE and EL of SubNc/Cl₆-PhOSubPc-based devices under strong coupling. a EQE (upper panel) and normalized electroluminescence (EL) spectra (lower panel) of five SC-devices, for different transport layers’ thickness d, showing the redshift of the device’s absorption and emission for increasing d. Different values of d lead to different cavity lengths and resonance wavelengths for the cavity photons. The five devices were exemplarily selected for the investigated range d, and the full series of devices is shown in Supplementary Fig. 2. b Simulated photoactive absorption (false color) in cells with varying d showing the formation of polariton branches with pronounced anti-crossing at overlapping points of the cavity and exciton resonances (dashed lines). The simulation results agree well with the calculated polariton branches (solid lines) of a coupled oscillator model and the experimental EQE data (red squares). c Comparison between EQE and EL peaks of the LP peak for various d. The colored numbers (in nm and meV) denote the Stokes shift in each case. The minimal Stokes shifts confirm that the investigated devices operate in the strong coupling regime