The absorption and emission properties of excitons are investigated in a pure 'red'phase of luminescent polydiacetylene wires. The values of the binding energy (Eb= 0.556 eV) and Bohr radius (r∼ 14Å) make the 'red'exciton similar to the one of the extensively studied 'blue'phase, so the conformational modifications which lead to a reordering of excited states and luminescent emission do not strongly affect the exciton structure. The opening of a ...
