Bathochromic shift in absorption spectra of conjugated polymer nanoparticles with displacement along backbones

., red shift) of the absorptionspectra has been observed for many thin films of conjugatedpolymers because of re-distribution of π-electrons in the con-jugated backbones due to the close proximity to each other inthe condensed state. This chromic phenomenon extended theabsorption area of the polymer in the visible range, thus lead-ing to enhanced photocurrent and photoconversion efficiencyof polymeric photovoltaic devices.