An intrinsic electrical conductivity study of perovskite powders MAPbX (X = I, Br, Cl) to investigate its effect on their photovoltaic performance.

An investigation into the intrinsic electrical conductivity of perovskite powders MAPbX, where X represents iodine (I), bromine (Br), or chlorine (Cl), was conducted to explore its impact on their photovoltaic performance. Results revealed that MAPbCl demonstrated light absorption ability in the ultraviolet and visible regions, while MAPbBr showed capacity for light absorption at longer wavelengths in the visible spectrum. On the other hand, MAPbI exhibited good absorption at longer wavelengths, indicating its ability to absorb light in the near-infrared region.

A study of the effects of the polarity of the solvents acetone and cyclohexane on the luminescent properties of tryptophan.

The luminescent properties of tryptophan in solvents less polar than water, such as acetone, and non-polar ones, such as cyclohexane, are experimentally studied and compared with theoretical calculations using time-dependent density functional theory (TD-DFT) methods. Since tryptophan may present different configurations and charge distributions, the most stable conformer is analyzed for both solvents, including its neutral and zwitterionic forms. To perform the simulation two clusters are proposed with the Zpt conformer in acetone: [Formula: see text] and [Formula: see text] , and four clusters with the Nag conformer in cyclohexane: (Trp)-(CH), (Trp)-(CH), (Trp)-(CH) and (Trp)-(CH), in order to conveniently emulate the concentration in each solvent by reducing the distance between adjacent tryptophan molecules as the concentration increases, since there is no control over the volume parameter.

Harnessing the Aqueous Chemistry of Silicon: Self-Assembling Porous Silicon/Silica Microribbons.

The synthesis of microribbons based on the assembly of porous silicon nanoparticles (pSiNPs) in a silica matrix is reported. The formation of these structures is driven by dissolution and reprecipitation of silica derived from the NPs upon drying of an aqueous colloidal dispersion. The process generates composite films that fracture into filaments due to geometric stresses associated with drying of the film on a curved surface.

Demonstration of photon Bloch oscillations and Wannier-Stark ladders in dual-periodical multilayer structures based on porous silicon.

: Theoretical demonstration and experimental evidence of photon Bloch oscillations and Wannier-Stark ladders (WSLs) in dual-periodical (DP) multilayers, based on porous silicon, are presented. An introduction of the linear gradient in refractive indices in DP structure, which is composed by stacking two different periodic substructures N times, resulted in the appearance of WSLs. Theoretical time-resolved reflection spectrum shows the photon Bloch oscillations with a period of 130 fs.

Tunable resonance transmission modes in hybrid heterostructures based on porous silicon.

: In this work, we report the experimental results and theoretical analysis of strong localization of resonance transmission modes generated by hybrid periodic/quasiperiodic heterostructures (HHs) based on porous silicon. The HHs are formed by stacking a quasiperiodic Fibonacci (FN) substructure between two distributed Bragg reflectors (DBRs). FN substructure defines the number of strong localized modes that can be tunable at any given wavelength and be unfolded when a partial periodicity condition is imposed.