Related papers: Fundamental limit of light trapping in grating str…
Light trapping for solar cells can reduce production cost and improve energy conversion efficiency. Understanding some of the basic theoretical constraints on light trapping is therefore of fundamental importance. Here, we develop a general…
Establishing the fundamental limit of nanophotonic light-trapping schemes is of paramount importance and is becoming increasingly urgent for current solar cell research. The standard theory of light trapping demonstrated that absorption…
Light trapping in solar cells allows for increased current and voltage, as well as reduced materials cost. It is known that in geometrical optics, a maximum 4n^2 absorption enhancement factor can be achieved by randomly texturing the…
Enhancing the absorption and emission of electromagnetic waves over a broad range of wavelengths is a topic of fundamental and applied interest in photonics and energy research. In the context of light trapping in solar cells, for example,…
Understanding the maximal enhancement of solar absorption in semiconductor materials by light trapping promises the development of affordable solar cells. However, the conventional Lambertian limit is only valid for idealized material…
We calculate the maximal absorption enhancement obtainable by guided mode excitation in a weakly absorbing dielectric slab over wide wavelength ranges. The slab mimics thin film silicon solar cells in the low absorption regime. We consider…
We introduce a limit for the strength of coupling light into the modes of solar cells. This limit depends on both a cell's thickness and its modal properties. For a cell with refractive index n and thickness d, we obtain a maximal coupling…
We investigate the angular behavior of the upper bound of absorption provided by the guided modes in thin film solar cells. We show that the 4n^2 limit can be potentially exceeded in a wide angular and wavelength range using two-dimensional…
One-dimensional lamellar gratings allow a particularly efficient way for solving Maxwell's equations by expanding the electromagnetic field in the basis of exact eigenmodes of the Helmholtz equation. Then, the solution can be expressed…
We address the question of the optimal broadband absorption of waves in an open, dissipative system. We develop a general framework for absorption induced by multiple overlapping resonances, based on quasi-normal modes and radiative and…
In this paper, we calculate the material specific absorption accurately using a modal method by determining the integral of the Poynting vector around the boundary of a specific material. Given that the accuracy of our method is only…
We report on the fabrication of two-dimensional periodic photonic nanostructures by nanoimprint lithography and dry etching, and their integration into a 1-{\mu}m-thin mono-crystalline silicon solar cell. Thanks to the periodic…
The ability to absorb light is indispensable for high efficient solar power generation. This places conflicting requirements on the structure of a solar cell: On one hand, it needs to have thick active layers to absorb more of the available…
A simple thermodynamic argument related to a (weakly absorbing) finite dielectric slab illuminated by sunlight- originally suggested by Yablonovich- leads to the conclusion that the absorption in a dielectric can at best be increased by a…
2D materials provide a platform for strong light--matter interactions, creating wide-ranging design opportunities via new-material discoveries and new methods for geometrical structuring. We derive general upper bounds to the strength of…
Absorption and scattering of electromagnetic waves by dielectric media are of fundamental importance in many branches of physics. In this Letter we analytically derived the ultimate upper limits for the absorbed and scattered powers by any…
The perfect absorption of light in subwavelength thickness layers generally relies on exotic materials, metamaterials or thick metallic gratings. Here we demonstrate that total light absorption can be achieved in ultra-thin gratings…
We theoretically demonstrate the fundamental limit in volume for given materials (e.g. Si, a-Si, CdTe) to fully absorb the solar radiation above bandgap, which we refer as solar superabsorption limit. We also point out the general…
The photosensitivity of silicon is inherently very low in the visible electromagnetic spectrum, and it drops rapidly beyond 800 nm in near-infrared wavelengths. Herein, we have experimentally demonstrated a technique utilizing…
Random surface texturing of an optically-thick film to increase the path length of scattered light rays, first proposed nearly thirty years ago, has thus far remained the most effective approach for photon absorption over the widest set of…