Bi-Functional Silica Nanoparticles Doped with Iron Oxide and CdTe Prepared by a Facile Method

Cadmium telluride (CdTe) and iron oxide nanoparticles doped silica nanospheres were prepared by a multistep method. Iron oxide nanoparticles were first coated with silica and then modified with amino group. Thereafter, CdTe nanoparticles were assembled on the particle surfaces by their strong interaction with amino group. Finally, an outer silica shell was deposited. The final products were characterized by X-ray powder diffraction, transmission electron microscopy, vibration sample magnetometer, photoluminescence spectra, Fourier transform infrared spectra (FT-IR), and fluorescent microscopy. The characterization results showed that the final nanomaterial possessed a saturation magnetization of about 5.8 emu g−1and an emission peak at 588 nm when the excitation wavelength fixed at 380 nm

Role of Textured Silicon Surface in Plasmonic Light Trapping for Solar Cells: The Effect of Pyramids Width and Height

Silicon solar cells with different front texturization are used for understanding pyramidal size influence on plasmonic light trapping. Cells with different pyramidal heights and widths have shown strong light back scattering in the surface plasmon resonance (SPR) region and minimal light forward scattering in the off-resonance region of silver nanoparticles (NPs). On the other hand, cell surface with similar pyramidal heights and widths has shown reduced back scattering in the SPR region, as well as enhanced light forward scattering in the off-resonance region of NPs with good optical impedance matching. The reason for these types of light interaction with NPs (nanoscale) and textured silicon (micrometer-scale) is explained, and plasmonic textured silicon solar cell performance with different pyramidal sizes using quantum efficiency measurements is verified

Internal quantum efficiency analysis of plasmonic textured silicon solar cells: surface plasmon resonance and off-resonance effects

Silver nanoparticles (Ag NPs) of various sizes and concentration were integrated on textured silicon solar cells for further confinement of incident light, generated photocurrent modifications were investigated using spectrally resolved short-circuit current measurements. Internal quantum efficiency (IQE) spectra were used for quantifying the effective minority carrier diffusion lengths (Le(ff)) of plasmonic cells in the long wavelength region (850 < lambda < 1020 nm). The L-eff of an optimized plasmonic solar cell enhanced to 431 mu m compared to 338 mu m of the bare cell, which is due to interacting Ag NPs' scattered fields, leading to enhanced light absorption in the plasmonic cell. Despite the enhanced L-eff values, the overall generated photocurrent reduced with Ag NPs which is due to the significant losses near the surface plasmon resonant region. Reduced IQE of plasmonic cells near and below the surface plasmon resonant region is due to size-dependent parasitic absorption and enhanced back scattering of Ag NPs, and a modified surface recombination process due to Ag NPs' strong near-fields

Tailoring Plasmonic Enhanced Upconversion in Single NaYF4:Yb3+/Er3+ Nanocrystals

By using silver nanoplatelets with a widely tunable localized surface plasmon resonance (LSPR), and their corresponding local field enhancement, here we show large manipulation of plasmonic enhanced upconversion in NaYF4:Yb(3+)/Er(3+) nanocrystals at the single particle level. In particular, we show that when the plasmonic resonance of silver nanolplatelets is tuned to 656 nm, matching the emission wavelength, an upconversion enhancement factor ~5 is obtained. However, when the plasmonic resonance is tuned to 980 nm, matching the nanocrystal absorption wavelength, we achieve an enhancement factor of ~22 folds. The precise geometric arrangement between fluorescent nanoparticles and silver nanoplatelets allows us to make, for the first time, a comparative analysis between experimental results and numerical simulations, yielding a quantitative agreement at the single particle level. Such a comparison lays the foundations for a rational design of hybrid metal-fluorescent nanocrystals to harness the upconversion enhancement for biosensing and light harvesting applications