We　have　systematically　investigated　the　dependence　of　open-circuit　voltage　(Voc)　on　the　element　components　in　Cu2ZnSnS4　(CZTS)　thin　film　fabricated　by　sputtering/sulfuration　approach.　It　was　found　that　more　Sn　would　remain　in　the　final　film　with　the　increase　of　Sn　content　in　the　precursor　even　after　annealing　at　high　temperature.　The　excess　Sn　will　greatly　reduce　the　Voc　and　degrade　the　performance.　On　the　contrast,　with　the　increase　of　Zn　content,　the　open-circuit　voltage　was　observed　to　increase　with　higher　Zn　content,　resulting　in　the　efficiency　improvement.　(C)　2017　Elsevier　B.V.　All　rights　reserved.