The influence of electromagnetic scattering by Au and silica nanoparticles placed atop silicon photovoltaic devices on absorption and photocurrent generation has been investigated. The nanoparticles produce substantial increases in power transmission into the semiconductor and consequently photocurrent response from ϳ500 toϾ 1000 nm. Increases in power conversion efficiency under simulated solar irradiation of up to 8.8% are observed experimentally, and numerical simulations provide quantitatively accurate predictions of these observed enhancements. Additional simulations indicate that these concepts can be applied to a broad range of photovoltaic device structures, including those based on low-index materials for which conventional antireflection coatings are problematic.

Articles you may be interested inMinimized open-circuit voltage reduction in GaAs/InGaAs quantum well solar cells with bandgap-engineered graded quantum well depths Optical properties of multi-stacked InGaAs/GaNAs quantum dot solar cell fabricated on GaAs (311)B substrate

We report on a pump -probe study of CoMoCAT nanotube suspensions with narrow chirality distribution. Visible pump pulses and a white light continuum are used for resonant excitation of the strongest dipole allowed E 22 subband exciton in the semiconducting (6, 5) tube and for broadband probe of the resulting spectral transients between 1300 nm and 480 nm, respectively. Transient spectra show signatures of both photobleaching (PB) and photoabsorption (PA) with practically identical decay-but slightly different risetimes. The experiments reveal that apparent variations of decay rates at different wavelengths do not reflect dynamics of different relaxation processes but are a consequence of the superposition of PB and blue-shifted PA response.

No abstract

Simulations of thin film (~2.5 µm thick) InGaAs/GaAs quantum well solar cells with various back side reflective and planar, symmetric scattering structures used for light trapping have been performed using rigorous coupled-wave analysis. Two-dimensional periodic metal/dielectric scattering structures were numerically optimized for Airmass 0 photocurrent generation for each device structure. The simulation results indicate that the absorption spectra of devices with both reflective and scattering structures are largely determined by the Fabry-Perot resonance characteristics of the thin film device structure. The scattering structures substantially increase absorption in the quantum wells at wavelengths longer than the GaAs absorption edge through a combination of coupling to modes of the thin film device structures and by reducing parasitic metal absorption compared to planar metal reflectors. For Airmass 0 illumination and 100% carrier collection, the estimated short-circuit current density of devices with In(0.3)Ga(0.7)As/GaAs quantum wells improves by up to 4.6 mA/cm(2) (15%) relative to a GaAs homojunction device, with the improvement resulting approximately equally from scattering of light into thin film modes and reduction of metal absorption compared to a planar reflective layer.