Photochromic　(PC)　materials　have　potential　applications　in　the　fields　of　memory,　anti-counterfeiting　due　to　their　reversible　writable/erasable　properties.　The　common　organic　PC　films　are　restricted　during　applications　owing　to　the　strict　requirements　of　thermal　stability　and　waterproof　of　devices.　Additionally,　most　of　the　PC　materials　strongly　rely　on　external　conditions　(irradiation/heat)　to　realize　reversible　PC　regulations,　which　may　cause　irreversible　damage　to　devices　(reduce　the　performance　and　service　life).　Hence,　it　is　imperative　to　develop　new　inorganic　membrane　materials　with　PC　self-recovery　behavior.　Here,　a　novel　strategy　to　achieve　completely　reversible　PC　regulation　based　on　the　K0.5Na0.5NbO3　(KNN)　based　thick　films　is　reported.　It　is　worth　noting　that　the　PC　self-recovery　behavior　can　be　optimized　via　forming　the　inter-electronic-levels　in　the　band　gap　via　Tm/Yb　co-doping　in　KNN,　alleviating　the　barrier　of　carrier　transition　from　valence　band　to　conduction　band　and　heightening　the　recombination　efficiency　of　carriers.　And　the　obtained　thick　films　manifest　a　reversible　PC　self-recovery　reaction　within　6　min.　This　work　is　expected　to　provide　the　effective　guidance　for　facilitating　the　further　utilization　of　PC　materials.　©　2022　Elsevier　Ltd　and　Techna　Group　S.r.l.