Figure 1

Figure 1: (a) 2D correlation spectrum of BIC J-aggregates. The black lines indicate the minima and maxima of the spectral feature with respect to the exciton absorption energy. (b) Coherence length, N, as a function of exciton absorption energy. The coherence length of the lowest energy exciton is 48 molecules. (c) Projection of the 2D correlation spectrum to the exciton emission energy axis (equivalent to a pump-probe spectrum) yields an exciton coherence length of 17 molecules.