Temperature evolution of the electronic band structure of the undoped and doped regioregular analog of poly(3hyphen;alkylthiophenes): A spectroscopic and theoretical study

摘要

The undoped and ferric chloridephyphen;doped lsquo;lsquo;headhyphen;tohyphen;headrsquo;rsquo; lsquo;lsquo;tailhyphen;tohyphen;tailrsquo;rsquo; analog of poly(3hyphen;decylthiophene) obtained from substituted bithiophenes, i.e., poly(4,4rsquo;didecylhyphen;2,2rsquo;bithiophene)hyphen;PDDBT has been investigated. The samples were studied by means of ultraviolet photoelectron spectroscopy, optical absorption measurements, and polymer bands structure calculations. Experiments were carried out at different temperatures between 100thinsp;deg;C and minus;180thinsp;deg;C. The results indicate that PDDBT is nonplanar in the undoped state. No temperature effects have been observed in the pgr;hyphen;electron properties. In the doped state, however, lowering of the temperature results in an increase of the system planarity that modifies the electronic band structure. This effect has been shown to be fully reversible with temperature.