Diamond functionalization with light-harvesting molecular wires: improved surface coverage by optimized Suzuki cross-coupling conditions

Donor-acceptor type light-harvesting molecular wires are covalently attached to a boron-doped diamond surface via a combination of diazonium electrografting and Suzuki cross-coupling. For the Suzuki reaction, various catalytic systems are compared with respect to their imposed surface coverage. Combining 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos) and Pd(0), the diamond coverage improves considerably (by 98%) as compared to the standard tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)(4)) catalyst. As the energy levels between the molecular chromophores and the diamond film align well, the sophisticated functionalized diamond surfaces present a first step towards the development of fully carbon-based devices for light to electricity conversion.