An energy conversion efficiency of 35% was obtained at 1-sun, air mass 1.5 for a novel silicon cell. The critical feature of the cell structure is the inclusion of local defect layers near a p-n junction. The local defect layers were proven to hold the key to achieving the exceptionally high efficiency of the novel cell fabricated via noncomplex processing.

ratio, high stiffness, high damping capacity, good elastic modulus, good castability and unique biodegradability in the physiological environment [1][2][3][4]. However, their applications are limited by the poor high-temperature strength and creep resistance.To improve the strength of magnesium alloy, it is a reliable way to refine the grain size using effective nucleants during the casting process. ZrB 2 nanoparticle are such effective nucleants and they are capable of inducing finer long-period stacking ordered phase (nano-LPSO-layer) formation due to the nano-surface effect and finally resulting in the formation of nanograins in magnesium alloys [5]. Also, it is a suitable way to improve the magnesium alloys' stiffness, elastic modulus and wear resistances by preparing particle reinforced magnesium matrix composites since ceramic particles have high strength, hardness and high-wearing features [6,7]. Compared with SiC and TiC particles, ZrB 2 particle reinforced magnesium-based composites fabricated by a direct melt-mixing method [8] have the best strength [9]. The stress transfers from Mg matrix to ZrB 2 reinforcement through the ZrB 2 /Mg interface, and the micro-hardness, fatigue resistance and friction factor of the composites are directly affected by interface bonding [10,11].Up to now, it is known that for effective heterogeneous nucleants in magnesium melt or effective reinforcements in particle reinforced magnesium matrix composites, the lattice mismatch and the chemical interaction play important roles in the overall interfacial energy [12]. And, the ZrB 2 /Mg interface will seriously influence the nucleating in Mg melt [5] or the strength of the composites [13]. Hence, the main purpose of this work was to investigate the mechanism of interface bonding of Mg/ZrB 2 in atomic level and help to improve the mechanical properties of the material.First-principles calculation is a powerful method to provide fundamental information at atomic or electronic level. Generally, (001) plane is a stable low index plane for

CuInTe 2 chalcopyrite compound is widely used in the fields of optoelectronics and pyroelectricity, and doping atoms can further improve the physical properties of the CuInTe 2 compound. For all we know, this is the first time that the elastic behaviors and lattice dynamical properties of Ag-doped CuInTe 2 compounds with the tetragonal system are determined theoretically. The elastic, lattice dynamical and thermal properties of Cu 1−x Ag x InTe 2 (x=0, 0.25, 0.5, 0.75 and 1) compounds have been investigated by using density functional theory. The obtained elastic constants of Cu 1−x Ag x InTe 2 compounds indicate that these compounds are mechanically stable and elastic anisotropic. The anisotropy of the {001} plane is more obvious than those of the {100} and {010} planes. Additionally, with increasing Ag doping concentrations, the bulk and shear moduli of Cu 1−x Ag x InTe 2 compounds decrease and their toughness improves. The phonon spectra and density of states reveal that Cu (or Ag) atoms in Cu 1−x Ag x InTe 2 compounds form chemical bonds with Te atoms, and Cu-Te bonds are gradually replaced by Ag-Te bonds with increasing Ag doping concentration. Vibration modes of Cu 1−x Ag x InTe 2 compounds at the G point in the Brillouin zone show that each Cu 1−x Ag x InTe 2 (x=0 and 1) crystal includes five irreducible representations (A 1 , A 2 , B 1 , B 2 and E). As for Cu 1−x Ag x InTe 2 (x=0.25, 0.5 and 0.75) compounds, each crystal has three irreducible representations (A, B and E). The atomic displacements of several typical phonon modes in CuInTe 2 crystals have been analyzed to deepen the understanding of lattice vibrations in Cu 1−x Ag x InTe 2 compounds. With increasing Ag doping concentration, the Debye temperatures of Cu 1−x Ag x InTe 2 compounds decrease, while their heat capacities increase.

The elastic properties and plane acoustic velocity of double perovskite Sr2CaMoO6 and Sr2CaWO6 are investigated with the plane wave pseuedopotential method based on the first-principles density functional theory within the local density approximate (LDA) and the generalized gradient approximation (GGA). The calculations indicate that Sr2CaMoO6 and Sr2CaWO6 respectively have the the Mo-O and W-O stable octahedral structure. The bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio ν and Debye temperature were calculated based on the elastic constants. The three dimensional plane acoustic velocities and their projection are in calculated for each direction by solving the Christoffel’s equation systematically based on the theory of acoustic waves in anisotropic solids, the result shows of anisotropy of lattice vibration for Sr2CaMoO6 is stronger than Sr2CaWO6.