Black phosphorus quantum dots (BPQDs) are proposed as effective seed-like sites to modulate the nucleation and growth of CsPbI₂Br perovskite crystalline thin layers, allowing an enhanced crystallization and remarkable morphological improvement. We reveal that the lone-pair electrons of BPQDs can induce strong binding between molecules of the CsPbI₂Br precursor solution and phosphorus atoms stemming from the concomitant reduction in coulombic repulsion. The four-phase transition during the annealing process yields an α-phase CsPbI₂Br stabilized by BPQDs. The BPQDS/CsPbI₂Br core-shell structure concomitantly reinforces a stable CsPbI₂Br crystallite and suppresses the oxidation of BPQDs. Consequently, a power conversion efficiency of 15.47% can be achieved for 0.7 wt % BPQDs embedded in CsPbI₂Br film-based devices, with an enhanced cell stability, under ambient conditions. Our finding is a decisive step in the exploration of crystallization and phase stability that can lead to the realization of efficient and stable inorganic perovskite solar cells.

The rough concept of alkaline strength dominating activation was furtherly clarified, and KOH and K ₂ CO ₃ acted as an activation promoter and pathway modifier, respectively.

Carbon-based materials, commonly used as commercial anodes in lithium/sodium ion batteries, nevertheless suffer from sluggish kinetic properties. Constructing electrode materials with one-dimensional nanostructures that offer convenient ion/electron transport pathways can improve Li+/Na+ storage behavior. Recently, metal single-atom doping has also emerged as an effective strategy to enhance storage kinetics. However, it remains challenging to construct one-dimensional carbon materials doped with metal single atoms using simple methods to achieve outstanding Li+/Na+ storage performance. Herein, three-dimensional intertwined short carbon nanofibers (SCNFs) coupled with single atomic iron dopants were tailored through a hydrothermal strategy followed by high-temperature carbonization free from strong acids etching metals. In the SCNFs, only a trace amount of Fe (0.37 at.%) was introduced; the nitrogen-coordinated Fe single atoms and the nanofibers-intertwined structure promoted Li-ion adsorption, improved diffusion kinetics, and enhanced conductivity, thereby facilitating Li+/Na+ storage capacity. Acting as an anode in lithium/sodium batteries, SCNFs demonstrated an outstanding electrochemical performance. After assembling lithium ion batteries, the optimal Fe-N-C-2 exhibited a high reversible capacity of 903.4 mAh g-1 at 50 mA g-1 with retention of 518.7 mAh g-1 at 1.0 A g-1. For sodium-ion storage, Fe-N-C-2 preserved excellent high-rate cyclic stability, maintaining 152.6 mAh g-1 after 500 cycles at 0.5 A g-1. Moreover, the hydrothermal method is simple and convenient for large-scale preparation. Our strategy offers a heuristic perspective on the controllable design of nitrogen-coordinated atomic metals for energy storage applications.