Research Information System
Aggregate, vol.7, no.3, 2026 (ESCI, Scopus)
Manganese (Mn)-based halide perovskites have attracted tremendous attention due to their low-cost and environment-friendly characteristics. Nevertheless, their applications are hindered by limited photoluminescence (PL) efficiency and insufficient stability. Dimensional engineering offers a viable pathway to modulate their photophysical properties and enhance their robustness. Herein, we design 2D@3D perovskites based on the dimensional reduction of CsMnCl3·2H2O 3D perovskites via alternating cation interactions (ACIs) by employing chitosan as a polymeric spacer cation. ACI effectively stabilized the 2D@3D perovskite and passivated surface defects through enriched H-bonding. As such, the PL intensity can be boosted by 50 times with a PL quantum yield (PLQY) of 18.1%. Intriguingly, 2D@3D perovskites experienced valence transition (VT: Mn2+ → Mn4+) at high temperatures, resulting in NH4CsMnCl6 perovskite. Density functional theory calculations indicated that an interfacial orbital hybridization-driven reaction mechanism triggered VT, which was initiated by the synergistic effect of octahedral distortion and ACI within 2D@3D perovskite. Notably, the proposed VT perovskites exhibited narrowband emission of Mn4+ with remarkable air-, photo-, and thermally stability, achieving a PLQY up to 80.7%. This approach paves the way for exploring organic-inorganic interactions in designing highly luminescent Mn-based perovskites.