No abstract

Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences.

Metal-organic frameworks (MOFs), as a very promising category of porous materials, have attracted increasing interest from research communities due to their extremely high surface areas, diverse nanostructures, and unique properties. In recent years, there is a growing body of evidence to indicate that MOFs can function as ideal templates to prepare various nanostructured materials for energy and environmental cleaning applications. Recent progress in the design and synthesis of MOFs and MOF-derived nanomaterials for particular applications in lithium-ion batteries, sodium-ion batteries, supercapacitors, dye-sensitized solar cells, and heavy-metal-ion detection and removal is reviewed herein. In addition, the remaining major challenges in the above fields are discussed and some perspectives for future research efforts in the development of MOFs are also provided.

Among the heavy metal ions, copper(ii) can cause eye and liver damage at high uptake. The existence of copper ions (Cu(2+)) even with an ultralow concentration of less than 0.1 μg g(-1) can be toxic to living organisms. Thus, it is highly desirable to develop efficient adsorbents to remove Cu(2+) from aqueous solutions. In this work, without any surface functionalization or pretreatment, a water-stable zeolitic imidazolate framework (ZIF-8) synthesized at room temperature is directly used as a highly efficient adsorbent for removal of copper ions from aqueous solutions. To experimentally unveil the adsorption mechanism of Cu(2+) by using ZIF-8, we explore various effects from a series of important factors, such as pH value, contact time, temperature and initial Cu(2+) concentration. As a result, ZIF-8 nanocrystals demonstrate an unexpected high adsorption capacity of Cu(2+) and high removal efficiency for both high and low concentrations of Cu(2+) from water. Moreover, ZIF-8 nanocrystals possess fast kinetics for removing Cu(2+) with the adsorption time of less than 30 min. In addition, the pH of the solution ranging from 3 to 6 shows little effect on the adsorption of Cu(2+) by ZIF-8. The adsorption mechanism is proposed for the first time and systematically verified by various characterization techniques, such as TEM, FTIR, XPS, XRD and SEM.

Owing to its excellent electrocatalytic properties, cobalt disulfide (CoS2) is regarded as a promising counter electrode (CE) material for dye-sensitized solar cells (DSSCs). However, hindered by its relatively poor electrical conductivity and chemical instability, it remains a challenge to apply it into high-performance DSSCs. In this work, we have developed novel CoS2 embedded carbon nanocages as a CE in DSSCs, using ZIF-67 (zeolitic imidazolate framework 67, Co(mim)2, mim = 2-methylimidolate) as a template. The CoS2 samples sulfurized for different time lengths are prepared through a facile solution process. It is found that the sulfurization time can be optimized to maximize the DSSC efficiency and the DSSC based on the CoS2 embedded carbon nanocages sulfurized for 4 hours exhibits the highest photovoltaic conversion efficiency (PCE) of 8.20%, higher than those of DSSCs consisting of other CoS2 CEs and Pt-based DSSC (7.88%). The significantly improved DSSC PCE is contributed by the synergic effect of inner CoS2 nanoparticles and an amorphous carbon matrix, leading to a CE with high catalytic activity, good electrical conductivity and excellent durability. This study demonstrates that the CE based on inexpensive CoS2 embedded carbon nanocages is a prospective substitute to expensive platinum and provides a new approach for commercializing high-efficiency DSSCs.