Water-soluble　orthorhombic　colloidal　SnSe　quantum　dots　with　an　average　diameter　of　4　nm　were　successfully　prepared　by　a　novel　irradiation　route　using　an　electronic　accelerator　as　a　radiation　source　and　hexadecyl　trimethyl　ammonium　bromide　(CTAB)　as　a　surfactant.　The　quantum　dots　exhibit　a　large　direct　bandgap　of　3.89　eV,　greatly　blue　shifted　compared　with　that　of　bulk　SnSe　(1.0　eV)　due　to　the　quantum　confinement　effect.　The　quantum　dots　show　blue　photoluminescence　at　similar　to　420　nm.　The　influence　of　CTAB　on　the　growth　of　the　quantum　dots　was　investigated　and　a　possible　reaction/growth　mechanism　was　proposed.　(C)　2011　Elsevier　Ltd.　All　rights　reserved.