The control of pulsed-laser-induced
deposition was studied with the case of ZnO crystallization in a hydrothermal
reaction. Crystal orientation, morphologies, and growth rate were
observed to vary under different pulsed-laser irradiation conditions.
Different energy barriers during nucleation and crystal growth processes
were determined by stepped changes of input energy levels of a pulsed
laser with the corresponding observations of the states of the material.
Therefore, by precisely adjusting the pulsed-laser energy that overcomes
a particular energy barrier, ZnO crystals with desired orientation
and morphology could be obtained on a seedless substrate in a catalyst-free
environment. Crystals varied in morphologies showed different behavior
in laser-induced growth, and growth rates were orders of magnitude
higher than those of other hydrothermal reactions. By analyzing crystal
growth characteristics in the reaction/diffusion-limited region,
a set of guidelines were defined to tune the dimensions of ZnO crystals.
Laser-induced crystal growth will benefit nanomanufacturing by providing
a practical tool to tune the morphology of nanomaterials in a precise
and effective manner, and it will bring deeper insight into the thermodynamic
and kinetic mechanisms in hydrothermal reactions.
In order to facilitate the shift towards sustainability in the building industry, development of building‐specific sustainability assessment tools that evaluate and integrate related environmental and socioeconomic impacts is needed. Existing assessment tools mainly focus on environmental and economic issues and give limited consideration on social sustainability. This study fills this gap through proposing an integrated building‐specific sustainability assessment model. This model was developed based on a conceptual model of life cycle sustainability assessment (LCSA), which is theoretically a combination of environmental life cycle assessment, life cycle cost analysis, and social life cycle assessment. An integrated AHP‐ELECTRE approach was adopted to provide a logical backbone for the model. This LCSA model is demonstrated through a case study to choose the best alternative regarding sustainability from three structural designs, that is, modular construction‐based, semiprefabricated, and conventional designs. Results show that semiprefabricated design is the best option in the context of this study.
Cesium lead halide perovskite nanocrystals (NCs) have compelling photoelectric properties while their poor stability severely impedes their practical applications. Herein, we demonstrate novel CsPbBr3-CsPbBr3 homostructured NCs induced by thioacetamide-Oleyamine (TAA-OAm)...
The rotation of organic cations is considered to be an important reason for the dynamic changes in stability and photoelectric properties of organic perovskites. However, the specific effect of organic cations rotation on formamidine based perovskite is still unknown. In our work, first-principles calculations based on density functional theory are used to examine the effect of the rotation of formamidine cations in FAPbI3 and FA0.875Cs0.125PbI3. We have comprehensively calculated the structure, electronic and optical properties of them. We found a coupling effect between formamidine cations rotation and cesium atom. This coupling effect changes the inclination angle of octahedron to regulate electron distribution, band gaps, and optical absorption. Hence, changing the cation orientation and substitution atom is a feasible way to dynamically adjust the energy band, dielectric constant and absorption edge of perovskite. Preparing perovskite with tunable properties is just around the corner through this way.
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