A facile and reproducible approach was reported to synthesize nanoparticle-attached SnO nanoflowers via decomposition of an intermediate product Sn6O4(OH)4. Sn6O4(OH)4 formed after introducing water into the traditional nonaqueous reaction, and then decomposed to SnO nanoflowers with the help of free metal cations, such as Sn2+, Fe2+, and Mn2+. This free cation-induced formation process was found independent of the nature of the surface ligand. It was demonstrated further that the as-prepared SnO nanoflowers could be utilized as good anode materials for lithium ion rechargeable batteries with a high capacity of around 800 mA h g(-1), close to the theoretical value (875 mA h g(-1)).

A nontoxic, simple, cheap, and reproducible strategy, which meets the standard of green chemistry, is introduced for the synthesis of ZnSe nanoparticles and nanoflowers. The production of these green nanomaterials can be readily scaled up and performed directly at ambient condition without affecting their qualities. The experimental results show that the as-synthesized ZnSe nanoparticles and nanoflowers with a zinc blende structure have a narrow size distribution without resorting to any postsynthetic size-selective procedure. A systematic study of the nanocrystal formation process indicates the following properties. (i) The amount of precursors plays a greater role in the determination of the nanoparticle size than other reaction parameters. Variation of this parameter allows us to tune the nanoparticle size in the high-temperature annealing process. This tunability is interpreted well by the growth kinetics. (ii) The limited ligand protection mechanism cannot be employed to explain the formation of our nanoflowers. Instead, a new growth mechanism is proposed. Upon heating at high temperature, a mononuclear Zn complex converts to a polynuclear Zn complex with multiple Zn atoms. Each Zn atom grows into one ZnSe nanoparticle after the injection of Se solution. These nanoparticles closely connect and thus look like nanoflowers.

The metastable wurtzite nanocrystals of CuGaS(2) have been synthesized through a facile and effective one-pot solvothermal approach. Through the Rietveld refinement on experimental X-ray diffraction patterns, we have unambiguously determined the structural parameters and the disordered nature of this wurtzite phase. The metastability of wurtzite structure with respect to the stable chalcopyrite structure was testified by a precise theoretical total energy calculation. Subsequent high-pressure experiments were performed to establish the isothermal phase stability of this wurtzite phase in the pressure range of 0-15.9 GPa, above which another disordered rock salt phase crystallized and remained stable up to 30.3 GPa, the highest pressure studied. Upon release of pressure, the sample was irreversible and intriguingly converted into the energetically more favorable and ordered chalcopyrite structure as revealed by the synchrotron X-ray diffraction and the high-resolution transmission electron microscopic measurements. The observed phase transitions were rationalized by first-principles calculations. The current research surely establishes a novel phase transition sequence of disorder → disorder → order, where pressure has played a significant role in effectively tuning stabilities of these different phases.