Polar Photovoltaic Effect in Chiral Alternating Cations Intercalation‐Type Perovskites Driving Self‐Powered Ultraviolet Circularly Polarized Light Detection

Abstract Chiral alternating cations intercalation‐type (ACI) perovskites, which are capable of great structural flexibility and a suitable quantum well barrier thickness that facilitates better charge transport, are urgently desired for circularly polarized light (CPL) detection. However, the chiral–polar photovoltaic effect (CPPE) in chiral ACI perovskites has never been reported although CPPE will provide great opportunities for future sustainable development. Here, by transmuting the organic ligands in 2D Ruddlesden–Popper‐type (RP) perovskites, two chiral–polar photovoltaic ACI perovskites (R/S‐PPA)EAPbCl 4 ( 1R / 1S ) are successfully developed, which are stabilized by the alternating ordering of the short alkyl EA (EA = ethylammonium) and chiral aromatic PPA (PPA = 1‐phenylpropylamine) cations in the interlayer space. Particularly, converting chiral RP into ACI perovskites gives rise to a remarkable CPPE and suitable quantum well barrier thickness. These features contribute to the exploration of self‐powered ultraviolet CPL detection with an asymmetry factor up to 0.4, which reaches the highest value among the reported layered chiral perovskites. This is thought to be the first realization of CPPE in ACI perovskites, which paves the way for the application of chiral perovskites for self‐powered short‐wave ultraviolet CPL detection.