Ultraviolet　(UV)-induced　damage　and　limited　solar　spectrum　utilization　often　hinder　the　performance　of　perovskite　solar　cells　(PSCs).　Here,　a　thermally　activated　delayed　fluorescent　(TADF)　molecule,　4CzIPN,　is　introduced　to　address　these　challenges.　Acting　as　a　down-conversion　agent,　4CzIPN　can　convert　UV　light　to　visible　light　via　Forster　energy　transfer,　enhancing　light　absorption　and　reducing　photon　loss.　Additionally,　it　can　bind　Pb2+　defects　and　prevents　organic　cation　degradation　through　cationic　it-effects,　stabilizing　the　perovskite　structure.　By　serving　as　a　crystal　growth　site,　4CzIPN　can　promote　intermediate　phase　formation　and　delay　the　crystallization　process,　and　improve　film　quality　while　mitigating　residual　stress　due　to　its　high　thermal　expansion　coefficient.　Furthermore,　its　UV　filtration　and　hydrophobic　properties　would　reduce　perovskite　decomposition　and　device　degradation.　These　advancements　yield　a　device　with　a　remarkable　power　conversion　efficiency　(PCE)　of　24.23　%　and　enhanced　optoelectronic　properties.　The　modified　device　demonstrates　outstanding　moisture　and　UV　light　stability,　retaining　90　%　of　its　initial　efficiency　after　1680　h　under　ambient　conditions　(25　+/-　5　degrees　C,　15　+/-　5　%　RH)　without　any　encapsulation.