We investigate the interplay effects of internal friction and solvent quality on the contact formation dynamics based on non-Markovian diffusion equation supplemented with an exponential sink term accounting for the electron transfer quenching. The mean contact formation time has been derived under Wilemski-Fixman approximation. We show that internal friction induces fractional viscosity dependence of looping time, which will be affected remarkably by solvent quality condition. Besides, internal friction promotes a diffusion-limited mechanism by slowing chain relaxation, while solvent quality being another key factor shifts the critical internal friction for the crossover of the transition from reaction to diffusion-limited regimes. (C) 2018 Elsevier B.V. All rights reserved.