“…In our rGO-Ag-Bi 2 O 3 /Bi 2 O 3− x substrate, the enhancement factor is better and comparable with that of the rGO-Ag substrate that was reported previously. 60 a ,66,67 Hence, the superior SERS enhancement in rGO-Ag-Bi 2 O 3 /Bi 2 O 2.75 is due to the synergistic effect of the PICT among the non-stoichiometric rGO-Bi 2 O 3 /Bi 2 O 2.75 system, plasmonic effect of Ag, molecular resonance or SERRS effect in R6G due to the excitation of 532 nm laser and exciton resonance in Bi 2 O 3 /Bi 2 O 2.75 .…”