OPTICAL AND CHARGE-TRANSPORT PROPERTIES OF DI-N-HEXYL SUBSTITUTED POLYSILYLENE AND POLYGERMYLENE

Optical and charge transport properties of poly(di-n-hexylsilylene), P D6S, and poly(di-n-hexylgermylene), PD6G, have been studied. The main- chain sigma-conjugation in both polymers leads to intense sigma-sigma UV-absorptions. A hypsochromic shift is observed for both polymers at the transition from a crystalline solid phase to a columnar mesophase . This transition is accompanied by disordering of the polymer backbon e which results in a decrease of the radiation induced microwave condu ctivity by a factor of 26 for PD6S and a factor of 4 for PD6G. In the disordered mesophase a charge carrier mobility of ca. 0.6x10(-6) m(2)/ Vs is found for both polymers. Charge carrier mobilities of 15x10(-6) m(2)/Vs and 2.4x10(-6) m(2)/Vs are found in the crystalline phase of P D6S and PD6G respectively, indicating a more ordered backbone for PD6S compared with PD6G.