A theoretical study of dye molecules adsorbed onto diamond (111) surfaces

Abstract

The combinations of different dye molecules adsorbed on 100% H‐terminated B‐doped diamond (111) surfaces, have been carefully simulated by using DFT under periodic boundary conditions. The dye molecules were C20H13NO3S4, C35H37NO2S3, C34H38OS2, C32H36OS2, and C31H35S3Br. The functional group within these dyes, behaves as an electron acceptor during a sunlight harvesting process. By comparing the upper valence band edge of the diamond surface with the HOMO and LUMO levels of the dyes in an energy diagram, a suitable scheme for a p‐type dye based solar cell was constructed. These functionalities were further confirmed by the observation of a partial degree of electron transfer from the diamond surface to the dye molecules. The combination of spectra for the dye molecules showed a wide absorption range from 200 to 620 nm. The effect of B doping on the binding of the dye molecules have furthermore been investigated. Shorter diamond//dye bonds are well correlated with large electron bond populations, and a larger degree of electron transfer. The former is regarded to be a measure of covalency, and the latter a measure of ionicity, in the interfacial bond.