Use of a Multiple Hydride Donor to Achieve an n Doped Polymer with High Solvent Resistance

Abstract

The ability to insolubilize doped semiconducting polymer layers can help enable the fabrication of efficient multilayer solution processed electronic and optoelectronic devices. Here, we present a promising approach to simultaneously n dope and largely insolubilize conjugated polymer films using tetrakis[ 4 1,3 dimethyl 2,3 dihydro 1H benzo[d]imidazol 2 yl phenoxy methyl]methane tetrakis O DMBI H , which consists of four 2,3 dihydro 1H benzoimidazole DMBI H n dopant moieties covalently linked to one another. Doping a thiophene fused benzodifurandione based oligo p phenylenevinylene co thiophene polymer TBDOPV T with tetrakis O DMBI H results in a highly n doped film with bulk conductivity of 15 S amp; 8239;cm 1. Optical absorption spectra provide evidence for film retention of amp; 8764;93 after immersion in o dichlorobenzene for 5 min. The optical absorption signature of the charge carriers in the n doped polymer decreases only slightly more than that of the neutral polymer under these conditions, indicating that the exposure to solvent also results in negligible dedoping of the film. Moreover, thermal treatment studies on a tetrakis O DMBI H doped TBDOPV T film in contact with another undoped polymer film indicate immobilization of the molecular dopant in TBDOPV T. This is attributed to the multiple electrostatic interactions between each dopant tetracation and up to four nearby anionic doped polymer segment