Ordered Element Distributed C3 N Quantum Dots Manipulated Crystallization Kinetics for 2D CsPbI3 Solar Cells with Ultra-High Performance

High-purity C3N quantum dots for enhancing fluorescence detection of metal ions

A new type of two-dimensional layered material, namely C3N, has been fabricated by polymerization and recommended to have great potential in various applications such as the development of electronic devices or photo-detectors, due to its enhanced conductivity, electronegativity, and unique optical properties. Actually, most of the present research on C3N is limited in the scope of theoretical calculation, while experimental research is blocked by inefficient synthesis with low purity and homogeneity. Here, we report an optimized efficient synthesis method of high-purity C3N QDs in aqueous solution by polymerization of DAP with combined centrifugation and filtration of products, with the synthesis yield up to 33.1 ± 3.1%. Subsequently, the C3N QDs have been used as novel metal ion probes exhibiting a sensitive fluorescent response to various metal ions including monovalent alkaline metals (Li+, Na+, and K+), divalent alkaline-earth metals (Mg2+, Ca2+, and Sr2+), and multivalent transition metals (Cu2+, Co2+, Ni2+, and Au3+, Fe3+, Cr3+) due to the high electronegativity of the C3N surface. Particularly, the fluorescent quenching response of Al3+, Ga3+, In3+, and Sc3+ ions is significantly different from the fluorescent enhanced response of most other carbon-based QDs, which is promising for enriching the detection methods of these metal ions and beneficial to improve the accuracy of ion recognition.

Additive Engineering for Stable and Efficient Dion-Jacobson Phase Perovskite Solar Cells

Because of their better chemical stability and fascinating anisotropic characteristics, Dion-Jacobson (DJ)-layered halide perovskites, which owe crystallographic two-dimensional structures, have fascinated growing attention for solar devices. DJ-layered halide perovskites have special structural and photoelectronic features that allow the van der Waals gap to be eliminated or reduced. DJ-layered halide perovskites have improved photophysical characteristics, resulting in improved photovoltaic performance. Nevertheless, owing to the nature of the solution procedure and the fast crystal development of DJ perovskite thin layers, the precursor compositions and processing circumstances can cause a variety of defects to occur. The application of additives can impact DJ perovskite crystallization and film generation, trap passivation in the bulk and/or at the surface, interface structure, and energetic tuning. This study discusses recent developments in additive engineering for DJ multilayer halide perovskite film production. Several additive-assisted bulk and interface optimization methodologies are summarized. Lastly, an overview of research developments in additive engineering in the production of DJ-layered halide perovskite solar cells is offered.