The　electric-field-modulation　(E-modulation)　of　photoluminescence　(PL)　properties　in　bulk　ceramics　has　attracted　tremendous　interest　due　to　its　potential　application　in　optical　data　storage　and　communication　devices.　One　promising　approach　of　reversibly　and　largely　modulating　the　PL　intensity　has　been　proposed　in　rare-earth　Er3+-doped　Pb0.96La0.04Zr0.9Ti0.1O3　(PLZT)　antiferroelectrics　(AFEs)　based　on　the　unique　E-dependent　antiferroelectric-ferroelectric　(AFE-FE)　phase　transition.　However,　the　AFE　phase　stability　of　PLZT　doped　with　various　Er　contents　and　their　E-modulated　PL　properties　have　not　been　systematically　investigated.　In　this　paper,　the　intrinsic　AFE　phase　of　PLZT-Er　is　found　to　be　stabilized　in　the　high-temperature　and　high-E　regions　with　increasing　Er3+　content.　The　enhanced　AFE　nature　caused　by　increasing　Er　doping　leads　to　a　larger　E-dependent　PL　tunability　(∼35%).　Moreover,　the　ceramics　exhibit　the　characteristics　of　both　upconversion　and　downconversion　PL　(UCPL　and　DCPL)　effects.　Based　on　the　excellent　E-dependent　dual-mode　PL　tunability,　an　optoelectronic　device　named　the　optical　latch　is　demonstrated,　where　an　electric　signal　can　be　used　to　trigger　a　notable　intensity　change　in　both　the　UCPL　and　DCPL　modes.　This　reversible　E-dependent　dual-mode　capability　in　PLZT-Er　sheds　light　on　a　feasible　approach　to　optoelectronic　applications.　©　2023　American　Chemical　Society.