Luminescent solar concentrators (LSCs) serve as large-area sunlight collectors, which are suitable for applications in semi-transparent, low-cost photovoltaics. Colloidal quantum dots (QDs) are promising candidates as a new type of absorber/emitter in LSCs, due to their size-tunable wide absorption spectrum, narrow emission spectrum, high quantum yield and structure-engineered large Stokes shift. However, due to the lack of long-term photo-stability of QDs, it is still a challenge to prepare photostable LSCs. Compared with colloidal QDs, carbon dots (C-dots) exhibit excellent photo-stability, presenting a very promising solution to improve the long-term photo-stability of quantum dot based LSCs. Here, as a proof-of-concept, we report the enhancement of the photo-stability of LSCs based on CdSe/CdS QDs by using a tandem structure of LSCs. We fabricated a large-area (∼100 cm²) thin film and placed this thin film on the top of a luminescent solar concentrator (LSC) based on CdSe/CdS QDs. The as-fabricated semi-transparent tandem device exhibits an external optical efficiency of ∼1.4% under one sun illumination, which is a 16% enhancement in the efficiency over the LSC based on CdSe/CdS QDs. More importantly, the presence of C-dots largely enhances the photo-stability of the LSC device based on CdSe/CdS QDs under ultraviolet (UV) illumination. After 70 hour UV illumination, the QD-based LSC with a protective layer of C-dot thin film retains 75% of its initial integrated photoluminescence intensity, which is 1.8 times higher than that of the LSC without the C-dot layer. Our work indicates that C-dots can be used as an additional layer in LSCs to enhance both the efficiency and long-term photo-stability.

The tetraoctylammonium bromide (TOAB)-stabilized gold nanoparticles have been successfully fabricated. After an annealing of the as-synthesized nanoparticles at 300 °C for 30 min, the coalescence behavior of gold nanoparticles has been investigated using high-resolution transmission electron microscopy in detail. Two types of coalescence, one being an ordered combination of two or more particles in appropriate orientations through twinning, and the other being an ordered combination of two small particles with facets through a common lattice plane, have been observed.

Oxidation of metals usually results in the formation of an oxide nanostructure with poorly controlled growth morphologies. By employing a simple mechanical approach that uses sandblasting to modify the surface roughness of iron substrates, we demonstrate that the morphologies of hematite (α-Fe₂O₃) nanostructures varying from the growth of one-dimensional nanowires to two-dimensional nanoblades can be achieved during the thermal oxidation of iron. Electron microscopy studies show that the effect of surface sandblasting is to effectively modify the oxide nucleation locations that define the growth shapes. The optical properties of hematite nanowires and nanoblades are examined for the demonstration of the morphology–property correlations.

Construction of novel electrode materials is an effective way to enhance the electrochemical performance of lithium ion batteries (LIBs). In this work, double-shell SnO₂@Fe₂O₃ hollow spheres are fabricated through a simple template method. It is revealed that the α-Fe₂O₃ nanorods are heterogeneously assembled on the surfaces of hollow SnO₂ spheres. The double-shell SnO₂@Fe₂O₃ hollow spheres, as an anode material for LIBs, demonstrate excellent lithium storage capacity and cycling stability. Their discharge specific capacity decreases to 464 mA h g⁻¹ for the 46th cycle at a current density of 100 mA g⁻¹, and then increases significantly to 1043 mA h g⁻¹ up to the 190th cycle. Compared with SiO₂@SnO₂ (221 mA h g⁻¹ after 190 cycles) and SnO₂ (336 mA h g⁻¹ after 190 cycles) electrodes, the better electrochemical performance of the SnO₂@Fe₂O₃ electrode is ascribed to its hierarchical hollow urchin-like structure, the SnO₂@Fe₂O₃ heterojunctions and the oxygen vacancies in the α-Fe₂O₃ nanorods. The sea urchin-like heterostructures dramatically inhibit the agglomeration and prevent the volume expansion during the cycling process. This work provides a novel way to construct a promising material with enhanced performance as an anode for LIBs.