Tristable　switching　nonvolatile　memory　(NVM)　devices　based　on　graphene　quantum　dots　(GQDs)　sandwiched　between　multi-stacked　poly　(methyl　methacrylate)　(PMMA)　layers　were　fabricated　on　indium-tin-oxide　(ITO)-coated　glass　substrates　by　using　a　solution-processed　method.　Current-voltage　(I-V)　curves　at　300　K　for　the　silver　nanowire/PMMA/GQD/PMMA/GQD/PMMA/ITO/glass　devices　showed　tristable　switching　currents　with　high-resistance,　intermediate-resistance,　and　low-resistance　states.　The　device＇s　cycling　endurance　of　the　three　resistance　states　remained　stable　with　a　distinguishable　value　for　each　resistance　state　over　1000　cycles,　and　the　obtained　retention　results　showed　well-distinguished　resistance　states　without　degradation　for　up　to　1　x　10(4)　s.　Schottky　emission,　Poole-Frenkel　emission,　trapped-charge　limited-current,　and　ohmic　conduction　were　proposed　as　the　dominant　conduction　mechanisms　for　the　fabricated　NVM　devices　based　on　the　obtained　I-V　characteristics.　The　described　energy-band　diagrams　confirm　the　proposed　conduction　band　mechanisms.　(C)　2016　Published　by　Elsevier　B.V.