Mn-Doped CsPbCl3 Nanocrystals with Mucic Acid Surface Passivation for Enhanced Performance in Photoresponsive Devices

The metal doping process not only enhances the intrinsic properties of semiconducting perovskite nanocrystals (PNCs), including optoelectronic, magnetic, and electrochemical properties, but also significantly improves their photophysical performance. For instance, Mn doping can enhance the photophysical properties of CsPbCl3 PNCs to some extent. In addition to doping, surface passivation is a promising strategy to further improve the photophysical properties and stability of these materials. In this study, we demonstrate that the surface defect states of the Mn-doped CsPbCl3 PNCs can be effectively reduced through postsynthesis surface passivation with mucic acid at room temperature, resulting in enhanced photophysical properties and stability. The XRD patterns confirmed the successful doping of Mn into the CsPbCl3 lattice. FTIR and XPS measurements verified the successful mucic acid passivation. Notably, the mucic acid-treated Mn–CsPbCl3 PNCs exhibited a photoluminescence quantum yield of 55–57%, compared to just 18% for unpassivated Mn–CsPbCl3. The photostability test confirms that passivated PNCs are more stable than those without passivation. The Mn-CPC-MA-3 PNCs showed significantly improved current stability and intensity under visible light illumination with a higher photocurrent density of ∼0.01 μA/cm2 versus −0.029 μA/cm2 for Mn-CPC PNCs.