Cation　exchange　occurs　via　defect　initiated　solid-state　diffusion,　a　process　that　can　lead　to　defect　formations.　The　effect　of　such　inherent　defect　formation　on　carrier　dynamics　of　cation-exchanged　heterostructures　remains　poorly　understood.　Herein,　we　report　exciton　dynamics　in　type　II　CdSe/PbSe　heterostructure　nanorods　formed　via　cation　exchange.　The　majority　of　electrons　in　CdSe　domains　decays　in　5　ps　due　to　ultrafast　carrier　trapping.　The　defect　generated　by　cation　exchange　can　be　healed　by　annealing　the　as-synthesized　CdSe/PbSe　heterostructure　nanorods.　This　study　suggests　a　strategy　for　improving　properties　of　heteronanostructures　prepared　by　cation　exchange　for　applications　in　photovoltaics　and　photocatalysis.　(C)　2017　Elsevier　B.V.　All　rights　reserved.