In general, the polarization value P can vary from -1 to +1, corresponding to perpendicular to parallel emission polarization with respect to the excitation polarization. When P = 0, the emission is not polarized towards a specific direction. The polarization images displayed in Figure (a-e) reveal a clear correlation between the P value of the nanofiber emission and the angle of the nanofiber growth axis () to the orientation of the excitation polarization. For the (R)-1NDI and (S)-2PDI mixture deposited on coated glass substrates, the emission polarization images (Figure ) demonstrates qualitatively the strong orientation dependence of the blue emission polarization: