The same inorganic backbone layer (SnI 4 - 6 ) leads to similar contributions to the potential PEA + space cation in the scattering region, therefore, contributes more to the quantum transport than the BA + spacer cation. Our calculations reveal that the conjugation of the benzene ring in the PEA + spacer cation makes the orbital more delocalization, as intuitively reflected in the lower ODI (Figure ). The average ODIs of BA + and PEA + spacer cation on the occupied molecular orbital are evaluated to be 55.11 and 31.33, respectively. The low ODI molecular orbital diagrams of BA + and PEA + are shown in Figure . Benefits to a relatively wider spatial delocalization stem from the benzene ring, PEA + spacer cation promotes a significant increment in the out-of-plane quantum transport.