Compound biomimetic structures for efficiency enhancement of Ga₀.₅In₀.₅P/GaAs/Ge triple-junction solar cells

Broadband antireflective nano-cones for tandem solar cells

Broadband solar cell antireflection coatings made of nano-cones are studied in square lattices of ZnS, TiO(2) and Si(3)N(4). In the best case, the spectrally integrated transmittance (accounting for both reflection and dielectric absorption losses) for direct solar radiation is 99 %, which represents a four-fold decrease in transmission losses in comparison to a standard antireflective coating bilayer. The dependence of the transmission as a function of nanostructure dimensions is studied, showing a wide maximum, thus leading to a high tolerance for manufacturing errors. This high transmittance is also robust against deviations from normal incidence. Our analysis suggests that the high transmittance is due not only to an effective gradual index effect, but is also due to light coupling to quasiguided modes in the photonic crystal leaking mostly towards the substrate.

Sensitized intense near-infrared downconversion quantum cutting three-photon luminescence phenomena of the Tm(3+) ion activator in Tm(3+)Bi(3+):YNbO(4) powder phosphor

In present study, the intense sensitized three photon near-infrared quantum cutting luminescence of Tm(3+) ion activator in Tm(3+)Bi(3+):YNbO(4) powder phosphor is reported. It is induced both by [{(1)G(4)→(3)H(4), (3)H(6)→(3)H(5)} or {(1)G(4)→(3)H(5), (3)H(6)→(3)H(4)}] and {(3)H(4)→(3)F(4), (3)H(6)→(3)F(4)} cross-energy transfer. We found that the 1820.0 nm (3)F(4)→(3)H(6) luminescence intensity of Tm(0.08)Bi(0.01)Y(0.91)NbO(4) powder phosphor excited by 302.0 nm is 151 and 8.38 times larger, compared to Tm(0.005)Y(0.995)NbO(4) excited by 302.0 and 468.0 nm, in which the quantum cutting takes place between Tm(3+) ions and Bi(3+) ion only acts as sensitizer. To the knowledge of the authors, it is the first time that the effective Bi(3+) sensitized near-infrared quantum cutting of Tm(3+) ion activator has been reported. It can facilitate the probing of the next-generation environmentally friendly germanium solar cell.