Cs-Cu-I perovskites have shown great potential in white light-emitting diodes (WLEDs) due to their unique self-trapped exciton (STE) radiative recombination with broad emission. However, their relatively low photoluminescence quantum yield (PLQY) limits practical applications. Here, we significantly enhance the PLQY of Cs₃Cu₂I₅ nanocrystals from 56% to 86% simply via Zn²⁺ aliovalent doping. Density functional theory calculations and temperature-dependent photoluminescence spectra reveal that Zn²⁺ preferentially occupies the tetrahedral Cu site, introducing a shallow defect level as an efficient radiative recombination center. Meanwhile, the Zn²⁺ doping increases the exciton binding energy to 309.5 meV and reconstructs electron-phonon coupling, thereby promoting the formation of STE. Furthermore, a white-emitting Cs-Cu-I mixture consisting of blue-emitting Cs₃Cu₂I₅ and yellow-emitting CsCu₂I₃ is obtained in situ via a one-pot method by adjusting the reaction temperature without post‑synthesis ratio adjustment. Based on this, a WLED with Commission Internationale de l’Éclairage (CIE) coordinates of (0.31, 0.33) and a color rendering index (CRI) of 89.2 is fabricated. Moreover, double perovskite (Cs₂Na_1-xAg_xIn_1-yBi_yCl₆, λ_em = 622 nm) is introduced to compensate for the insufficient red emission. The resulting WLED achieves standard white light with CIE coordinates of (0.33, 0.33), a high CRI of 94.5, and an R₉ value of 84. This device also exhibits excellent operational and environmental stability, along with an ultra-wide beam angle of 177°. This work not only clarifies the mechanism of ion doping in 0D perovskites but also provides a new pathway for constructing high-quality, environmentally friendly WLEDs for solid-state lighting.

Lead-free perovskites are promising for photodetector applications due to their excellent optoelectronic properties and low toxicity. However, the performance of perovskite-based photodetectors is often limited by defects in the films, leading to non-radiative recombination and reducing carrier mobility. In this work, we report the significant performance enhancement of CsBi₃I₁₀ perovskite photodetectors through Mn doping. Mn-doped CsBi₃I₁₀ films were prepared in an air environment, which still shows good stability. Structural and photoelectronic characterizations confirm that Mn doping effectively passivates defects, suppresses non-radiative recombination, and reduces the dark current. Furthermore, this doping strategy leads to a remarkably weak light detection feature and high reproducibility of the photodetectors. The optimized device achieves a responsivity of 1.11 A/W, a specific detectivity of 1.62 × 10¹² Jones, a fast response time of 4.53 (rise) and 1.47 μs (decay) under 650 nm illumination. Considering its special response spectrum and fast response under low-light conditions, a blood oxygen saturation monitoring system was successfully built on the Mn-doped CsBi₃I₁₀ perovskite, achieving high sensitivity. This work not only demonstrates an effective doping strategy for improving the performance of lead-free perovskite photodetectors but also highlights their potential as low-toxicity candidates for wearable health monitoring.