Effect of Doping different Percentages of Lithium Fluoride on Some Optical Characteristics of Poly-Methyl Methacrylate Polymer

This study implements the optical characteristics of Poly-Methyl methacrylate (PMMA) polymer before and after doping different percentages of Lithium Fluoride (LiF). Where the specimens were formulated as disk shape with diameter of (2.5 cm) and thickness of (0.148 cm) using Thermal pressing technology. The absorbance and reflectivity spectra were recorded in addition to their coefficients at range (300-1100) nm. Also, the study has included the determination of refraction and real and imaginary part of dielectric constant coefficients.

Improvement of the electromagnetic properties of blended electromagnetic shielding fabric of cotton/stainless steel/polyester based on multi-layer MXenes

Blended electromagnetic shielding (EMS) fabrics of cotton/stainless steel/polyester have been widely applied. The porous structure of the fabric is the guarantee of its good comfort performance, but it also hinders the improvement of shielding efficiency and the endowing of wave absorption performance. To solve the above problems, this paper proposes a mixed resistance field based on fabric pores by the construction of multi-layer MXenes. Ti3AlC2 is etched by hydrochloric acid and lithium fluoride to generate hydrofluoric acid in situ to prepare multi-layer Ti3C2T x. The finishing experiments are designed to finish the fabric around the pores with Ti3C2T x impregnation. The enhancement effect and mechanism of the mixed resistance field on the shielding effectiveness and wave absorbing properties of the fabric are analyzed. The result shows that the multi-layer Ti3C2T x for textile finishing is prepared quickly and effectively using the proposed method. The micro media of the Ti3C2T x in the dispersion are adsorbed on the surface of various fibers, most of which are cotton fibers. The shielding effectiveness of the finished EMS fabric is improved significantly in the frequency ranges of 6.57–14 GHz and 11.97–18 GHz. The wave absorbing performances in the frequency range of 11.97–18 GHz are excellent. It is proved that the effect of the mixed resistance field of the pores was satisfactory. This paper provides a new way for the application of Ti3C2T x in EMS fabric, solves the disadvantages caused by pores, and can provide a reference for the design and production of wave absorbing EMS fabric.

Simulated Study and Surface Passivation of Lithium Fluoride-Based Electron Contact for High-Efficiency Silicon Heterojunction Solar Cells

Numerical simulation and experimental techniques were used to investigate lithium fluoride (LiFx) films as an electron extraction layer for the application of silicon heterojunction (SHJ) solar cells, with a focus on the paths toward excellent surface passivation and superior efficiency. The presence of a 7 nm thick hydrogenated intrinsic amorphous silicon (a-Si:H(i)) passivation layer along with thermally evaporated 4 nm thick LiFx resulted in outstanding passivation properties and suppresses the recombination of carriers. As a result, minority carrier lifetime (τeff) as well as implied open-circuit voltage (iVoc) reached up 933 μs and iVoc of 734 mV, accordingly at 120°C annealing temperature. A detailed simulated study was performed for the complete LiFx based SHJ solar cells to achieve superior efficiency. Optimized performance of SHJ solar cells using a LiFx layer thickness of 4 nm with energy bandgap (Eg) of 10.9 eV and the work function of 3.9 eV was shown as: Voc=745.7 mV, Jsc=38.21 mA/cm2, FF=82.17%, and =23.41%. Generally, our work offers an improved understanding of the passivation layer, electron extraction layer, and their combined effects on SHJ solar cells via simulation.