Figure also shows examples of the conformational behaviour of the emitters after switching to the S 1 state force field at 5 ns. It is noteworthy, as can be seen in Figure , that the axial conformation in the CBP solid state host immediately switches to the equatorial (while the conformation in the other two simulations is relatively unchanged). Indeed, in all of our simulations the axial configurations flipped into the equatorial conformations within a few nanoseconds, even in the rigid, solid state environment of CBP and PYD2. This is expected given the very high energy of the axial conformation in the S 1 state (Figure ). Absorption and emission energies of PTZ-DBTO2 in the different environments are averaged over twenty MD runs and the results are summarised in Table . The in vacuo vertical excitation energies are calculated using the optimised geometries shown in Figure and.