The synthesis and study of so-called "nanoparticles", particles with diameters in the range of 1-20 nm, has become a major interdisciplinary area of research over the past 10 years. Semiconductor nanoparticles promise to play a major role in several new technologies. The intense interest in this area derives from their unique chemical and electronic properties, which gives rise to their potential use in the fields of nonlinear optics, luminescence, electronics, catalysis, solar energy conversion, and optoelectronics, as well as other areas. The small dimensions of these particles result in different physical properties from those observed in the corresponding macrocrystalline, "bulk", material. As particle sizes become smaller, the ratio of surface atoms to those in the interior increase, leading to the surface properties playing an important role in the properties of the material. Semiconductor nanoparticles also exhibit a change in their electronic properties relative to that of the bulk material; as the size of the solid becomes smaller, the band gap becomes larger. This allows chemists and material scientists the unique opportunity to change the electronic and chemical properties of a material simply by controlling its particle size. Research has already led to the fabrication of a number of devices. This review aims to highlight recent advances in the synthesis of compound semiconductor nanoparticle materials and their potential use in areas such as catalysis and electronic device fabrication.

The influence of the choice of complexing ligand, zinc counter-ion, pH, ionic strength, supersaturation, deposition time and substrate on the nature of ZnO films grown from chemical baths (CBD) are discussed. There are significant differences between CBD and similar routes such as hydrothermal methods for ZnO films. Modelling of speciation and experimental results suggest that acicular ZnO morphologies are best obtained by limiting the concentration of one of either Zn 21 or OH 2 in the presence of a large excess of the other. The presence of a prior ZnO layer can facilitate nucleation at lower levels of supersaturation and enable size tailoring of ZnO columns. The point at which the substrate is introduced into the bath is crucial and can lead to a significant difference in both the width of the rods and optical transparency of the films. HR-TEM has yielded important structural information and a growth mechanism for single crystalline ZnO rods by CBD is described for the first time.

We report the liquid exfoliation of black phosphorus in N-methyl-2-pyrrolidone to form few-layer phosphorene nanosheets.

Introduction 4417 2. Precursor Requirements 4418 3. Precursors for II-VI Materials 4418 3.1. Precursors for II-VI Thin Films 4418 3.1.1. Alternate Chalcogenide Precursors 4419 3.1.2. Adducts of Metal Alkyls 4419 3.1.3. Single-Molecule Precursors 4419 3.2. Precursors for II-VI Nanoparticles 4425 4. Precursors for III-V Materials 4428 4.1. Precursors for III-V Thin Films 4428 4.1.1. Alternative Group V Sources 4428 4.1.2. III-V Adducts 4429 4.1.3. III Nitrides 4429 4.1.4. III Phosphides and Arsenides 4430 4.1.5. III Antimonides 4431 4.2. Precursors for III-V Nanoparticles 4431 5. Precursors for III-VI Materials 4432 5.1. Precursors for III-VI Thin Films 4432 5.1.1. Thiolato Complexes 4432 5.1.2. Thiocarbamato Complexes 4433 5.1.3. Xanthato and Monothiocarbamato Complexes 4433 5.1.4. Dichalcogenoimidodiphosphinato Complexes 4433 5.2. Precursors for III-VI Nanoparticles 4434 6. Precursors for IV-VI Materials 4434 6.1. Precursors for IV-VI Thin Films 4434 6.2. Precursors for IV-VI Nanoparticles 4437 7. Precursors for V-VI Materials 4437 7.1. Precursors for V-VI Thin Films 4437 7.2. Precursors for V-VI Nanoparticles 4440 8. Conclusions 4441 9. Acknowledgments 4442 10. References 4442

Uniform mesocrystals of TiO2 (anatase) have been prepared from mesocrystals of NH4TiOF3. NH4TiOF3 was synthesized from an aqueous solution containing (NH4)2TiF6 and H3BO3 in the presence of a nonionic surfactant Brij 56, Brij 58, or Brij 700, at low temperatures. The exterior shapes of NH4TiOF3 mesocrystals can be tuned by adjusting the reagent concentration, reaction time, reaction temperature, and rate of stirring. The formation of the NH4TiOF3 mesocrystals proceeds via a self-assembly process involving nonclassical crystal growth. By sintering in air at 450 degrees C, or washing with H3BO3 solution at ambient temperatures, the NH4TiOF3 mesocrystals can be converted to mesocrystals of TiO2 (anatase), and the original architecture is retained.

Possible types of, and formation mechanisms for, mesocrystals are summarized. Mesocrystals are a new class of solid materials, which can be regarded as assemblies of crystallographically oriented nanocrystals. Mesocrystals have high crystallinity as well as high porosity, making them promising substitutes for single-crystalline and/or porous polycrystalline materials in many applications such as catalysis, sensing, and solar-energy conversion.

Summary: A drop‐on‐demand ink‐jet printer has been used to print a silver‐organic solution onto glass substrates. Conductive silver tracks were obtained by heat treatment of the ink‐jet printed deposits at temperatures ranging from 125 °C–200 °C in air. Resistivity values were found to have dropped to two to three times the theoretical resisitivity of bulk silver after temperatures of 150 °C and above were used.Resistivity values of a silver‐based ink.magnified imageResistivity values of a silver‐based ink.

The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported. The nanodispersed materials obtained show quantum size effects in their optical spectra and exhibit near band-edge luminescence. The influence of experimental parameters on the properties of the nanocrystallites is discussed. HRTEM images of these materials show well-defined, crystalline nanosized particles. Standard size fractionation procedures can be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2′-bipyrimidine, are used as the starting materials for the preparation of novel nanocomposites. The optical properties shown by these new nanocomposites are compared with those of the starting nanodispersed materials.