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In this study, the effect of seed-recrystallization on the Ag deposition onto silica sphere surfaces has been investigated. It was found that increasing the seed-recrystallization cycles resulted in higher atomic deposition at ca. 84% coverage of silica surfaces with the same mole ratio of Ag precursor characterized by the Ag/Si atomic ratio obtained by XPS analyses. The addition of straight-chain palm oil derived fatty alcohols (PODFA) in the sol-gel prior to seed-recrystallization aided the deposition of Ag. Thus, PODFA play the role of nonsurfactant surface modification agent to produce Ag-silica nanocomposite. Structural analyses showed that the resulting Ag nanocrystallines having a face centre cubic structure and particle size of 5–20 nm were deposited homogeneously on silica spheres. Chemical state analyses from XPS indicated that the increasing number of seed repetition process increased the seeding of Ag nanoparticles on silica surface with the same molar of Ag atoms. XPS spectra at O1s orbital elucidated that the binding energy of three oxides components were determined at ca. 533.8 eV (Si-O-H), 532.8 eV (Si-O-Si) and 530.8 eV (Si-O-Ag), respectively. The high sensitivity of surface plasmon resonance observed in the nanocomposites prepared in this study are useful in optical applications. [ABSTRACT FROM AUTHOR]

Abstract: In the present work monodispersed silica spheres were successfully synthesized using nonsurfactant approach of neutral palm oil derived fatty alcohols based microemulsions. The resulting silica spheres have diameter in two size clusters; ca. 560nm and ca. 700nm, respectively. The synthesis was acomplished by using straight chain fatty alcohols in a combined approach of sol–gel and Stöber method without extensive washing. Translucent nonsurfactant microemulsions containing straight chain fatty alcohols namely octyl alcohol (C8), decyl alcohol (C10) and dodecyl alcohol (C12) were successfully obtained. Short chain alcohols such as ethanol and methanol were used as co-solvent in the formation of silica spheres. Tetraethylorthosilicate were used as silica source as well as co-structure directing agent. The resulting silica spheres were successfully functionalized with octyl-4-methoxy cinnamate (OMC) as UV-absorbing compounds in a direct nonsurfactant co-condensation during the synthesis process. The technique employed was found to be most viable in producing silica spheres for applications as meta-atom in the fabrication of metamaterials. [Copyright &y& Elsevier]

The defects at the absorber and interface layer of organic-inorganic lead halide perovskite solar cells are unfavorable for efficiency as well as the stability. In this study, we have performed the numerical simulation on inverted planar structure perovskite solar cell based on NiO as a hole transport material (HTM) by SCAPS-1D. Here we investigated the effects of defect density and energy level of the perovskite absorber layer and perovskite/HTM interface layer on the performance, respectively. The analysis revealed that values of J sc , V oc , and FF of perovskite solar cells are significantly reduced with increasing the defect density of perovskite layer. The power conversion efficiency severely reduced from 25 to 5% when the defect density increased from 1013 to 1018 cm−3, respectively. A similar trend was also found in case of interfacial defect between Perovskite and HTM layer. It was found that the defect energy level more than 0.3 eV above conduction band of perovskite has almost no detrimental effect on the device's efficiency. [ABSTRACT FROM AUTHOR]

Abstract Organolead trihalide perovskite absorber layers are potential contenders in solar energy harvesting technologies because of their competitive lower fabrication cost, high power conversion efficiency, and ease of processing. The structural, interfacial and morphological properties are the key aspects to determine the stability and photon-to-current conversion efficiency of Perovskite solar cells (PSCs). Most contemporary research has emphasised on enhancing the power conversion efficiency (PCE) of perovskites by changing the fabrication process, solvent engineering, or precursor solution. With changes in these variables, the structure and morphology of perovskites also change, which affects the photon-to-current conversion efficiency and the stability of the PSCs. However, no stockpiled records have aided in conducting corresponding research outcomes on this perspective. In this review, we summarise the effect of fabrication method on the structure and morphology, as well as the PCE and stability of PSCs. This review will help readers decipher the scientific and technological challenges concerning hybrid inorganic–organic PSCs. Highlights • Deposition technique controls the structure and morphology of the perovskite layer and PCE of PSCs. • Pinhole and slower crystallisation were challenged for OSD method. • Inequality of grain size and surface smoothness is one of the shortcomings of SDM method. • Extremely uniform surface coverage, pinhole free and large grain size were obtained by TVD method • The CVD method has been widely used in the commercial deposition techniques. [ABSTRACT FROM AUTHOR]

Calcium phosphate coatings produced on the surface of Ti6Al4V by plasma electrolytic oxidation (PEO) using different concentrations of hydroxyapatite (HA) in a 0.12 M Na 3 PO 4 (NAP) electrolyte solution was investigated. It was found that the amount of calcium phosphate particles infiltrated into the coating layer as well as the thickness and the surface roughness of the coating increased with increasing HA concentration. The porosity of the ceramic coatings indicated an inverse relationship with the concentration of HA particles dispersed in the NAP solution. The result also demonstrates that higher scratch adhesive strength was achieved using 1.5 g/L HA solution, producing a critical load of 2099 mN, while 0 g/L HA only produced a critical load of 1247 mN. The adhesion becomes independent of thickness when the concentration of HA exceeds 1.5 g/L. The failure of the coating was characterized by large periodic hemispherical chipping, while intermittent delamination was noticed with the coating embedded with HA particles. This study demonstrate the viability of using PEO to produce a thin layer of HA ceramic coating on Ti6Al4V suitable for biomedical applications. [ABSTRACT FROM AUTHOR]