Influence of molecular distortion on the exciton quenching for quaterthiophene-terminated self-assembled monolayers on Au(111)

•We found n-parity-dependent lifetime τ for photoexcited 4T-(CH2)nS-SAMs on gold.•Independent of n, the quenching is due to an excitation energy transfer mechanism.•The n parity dependence of τ results from conformation change of -(CH2)nS- chains.•Importance of molecular design even in aliphatic parts for organic device is shown.