Metal ion doping is an efficient method to achieve high photocatalytic performance of semiconductors. However, the current synthetic methods by using inorganic salts as doped sources in the precursor reaction system might suffer from ion waste and second pollution. Herein, we developed a novel method by employing electrospun nanofibers as ion reservoir to release metal ions for the synthesis of ion-doped semiconductors with high photocatalytic activity . As demonstrated, Co/Fe co-doped BiOCl photocatalyst (Co/Fe-BOC) was facilely prepared in the presence of CoFe 2 O 4 nanofibers as Co and Fe ion reservoir via a simple solvothermal method . Compared with BiOCl, the resulted Co/Fe-BOC shows increased specific surface area, visible light response as well as separation and transportation efficiencies of photogenerated carriers. Thus, the Co/Fe-BOC exhibits significantly enhanced visible light photocatalytic activity to degrade 99.4% rhodamine B (RhB) within 4 min. This new doping approach not only avoids the ion waste and pollution during the reaction process but also facilitates the separation of the photocatalyst. Moreover, the CoFe 2 O 4 nanofibers could be repeatedly used as ion reservoir to prepare high-performance Co/Fe-BOC. This nanofiber-based ion doping approach provides a novel, universal and promising insight to obtain doped semiconductors with high photocatalytic activity.
Mixed-halide perovskites are emerging as excellent photovoltaic candidates because of their tunable bandgaps for semitransparent and tandem perovskite solar cells. However, the notorious film quality originated from the rapidly downward crystallization process susceptibly propagates enormous detrimental defects, which deteriorate the photovoltaic performance and accelerate halide segregation. To address this issue, herein, a multilayer alkalis-intercalated-vermiculite is employed as pre-buried interface modifier to regulate the perovskite lattice property. The matchable lattice structure between perovskite and vermiculite by forming Pb─O bond not only releases the interfacial strain during the film growth but also the embedded alkalis ions can gradually diffuse into perovskite lattice to form a favorable vertical gradient owing to the weak interlamellar van der Waals interaction, playing bis-roles of atomical lubricant and ion-reservoir to eliminate detrimental defects. As a result, the film quality and lattice stability is significantly improved with suppressed phase segregation for mixed-halide perovskites, accompanying a champion efficiency of 11.42% for carbon-based CsPbIBr 2 device, 15.25% for carbon-based CsPbI 2 Br device and 23.17% for p-i-n inverted (Cs 0.05 MA 0.05 FA 0.9 )Pb(I 0.93 Br 0.07 ) 3 cell. This work provides a new strategy on buried interface engineering for making high-efficiency and stable perovskite platforms.
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