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Using sunlight to produce hydrogen gas via photocatalytic water splitting is highly desirable for green energy harvesting and sustainability. In this work, Mn 2+ doped 1-dimensional (1D) CdS nanorods (NRs) with Pt tips ( i.e. , 1D Mn:CdS-Pt NRs) were synthesized for photocatalytic water splitting to generate hydrogen gas. The incorporation of Mn 2+ dopants inside the 1D CdS NRs with a significantly longer lifetime (∼ms) than that of host excitons (∼ns) facilitates charge separation; the electron transfer to metal Pt tips leads to enhanced photocatalytic activity in water splitting redox reactions. The as-synthesized Mn 2+ doped CdS NR-based photocatalyst generated an order of magnitude greater yield of hydrogen gas compared to the undoped CdS NR-based photocatalyst. The enhanced charge transport from the long lifetime excited state of Mn 2+ dopants in light harvesting semiconductor nanomaterials presents a new opportunity to increase the overall photocatalytic performance. 

Lead-free perovskites and their analogues have been extensively studied as a class of next-generation luminescent and optoelectronic materials. Herein, we report the synthesis of new colloidal Cs 4 M( ii )Bi 2 Cl 12 (M( ii ) = Cd, Mn) nanocrystals (NCs) with unique luminescence properties. The obtained Cs 4 M( ii )Bi 2 Cl 12 NCs show a layered double perovskite (LDP) crystal structure with good particle stability. Density functional theory calculations show that both samples exhibit a wide, direct bandgap feature. Remarkably, the strong Mn–Mn coupling effect of the Cs 4 M( ii )Bi 2 Cl 12 NCs results in an ultra-short Mn photoluminescence (PL) decay lifetime of around 10 μs, around two orders of magnitude faster than commonly observed Mn 2+ dopant emission in NCs. Diluting the Mn 2+ ion concentration through forming Cs 4 (Cd 1−x Mn x )Bi 2 Cl 12 (0 < x < 1) alloyed LDP NCs leads to prolonged PL lifetimes and enhanced PL quantum yields. Our study provides the first synthetic example of Bi-based LDP colloidal NCs with potential for serving as a new category of stable lead-free perovskite-type materials for various applications.