Exciton transfers are ubiquitous and extremely important processes, but often poorly understood. A recent example is the triplet exciton transfer in tetracene sensitized silicon solar cells exploited for harvesting high-energy photons. The present ab initio molecular dynamics calculations for tetracene-Si(111):H interfaces show that Si dangling bonds, intuitively expected to hinder the exciton transfer, actually foster it. This suggests that defects and structural imperfections at interfaces may be exploited for excitation transfer.