Near‐Field Optical Excitations in Silicon Subwavelength Light Funnel Arrays for Broadband Absorption of the Solar Radiation

Abstract

Broadband absorption is pivotal for the realization of green energy based on solar energy. Decoration of photovoltaic cells with arrays of subwavelength formations provides an efficient means for broadband absorption in thin films. Surface arrays of silicon light funnels (LFs) have been suggested as a promising platform to produce broadband absorption that is considerably superior to other subwavelength arrays such as the well‐known nanopillar (NP) arrays. The current study explores the underlying mechanism of broadband absorption in LF arrays. To this end, the optical near‐field of LF and NP arrays is experimentally probed using a near‐field scanning optical microscopy. It is shown that in LF arrays the near‐field increases as the array period decreases in contrast with NP arrays in which the near‐field decreases with decreasing array period. Also, the experimental near‐field of the arrays follows the numerically calculated absorption cross section of the array‐nested NPs/LFs. Therefore, the origin to the broadband absorption in compact LF arrays is due to field overlap of adjacent LFs which increases the absorption cross section of the individual LFs composing the array. This absorption cross‐sectional enhancement coupled with a higher filling ratio in compact arrays produces broadband absorption that is significantly greater than that of NP arrays.

Photon management by scratch‐resistant antireflection coating for the efficiency enhancement of silicon solar cell

“…The increased power of the solar cell signifies that more electron‐hole carriers are created and effectively extracted to the conducting layer of the solar cell due to the antireflective effect of the VTES/PF‐127 cover glass. The improvement in the total conversion efficiency of the solar cell validates the light‐trapping ability of the prepared VTES/PF‐127‐based porous structure and can be considered as a promising antireflecting cover glass for a photovoltaic system 47 …”

“…The improvement in the total conversion efficiency of the solar cell validates the light-trapping ability of the prepared VTES/PF-127-based porous structure and can be considered as a promising antireflecting cover glass for a photovoltaic system. 47 The current work further highlights that the hydrophobic antireflection-coated cover glass not only enhances PV performance but also maintains efficiency due to its good self-cleaning ability. This was tested by subjecting dusty-coated substrate over the solar cell and performing I-V characterization.…”

Light Trapping in Silicon Arrays of Deep Subwavelength Features for Absorption of the Solar Radiation

“…The 4 n 2 limit is based on geometrical optics, and it pursues surface decoration of both sides of the thin film in order to increase the optical power in the film. More recently, it was suggested and demonstrated that the 4 n 2 limit can be exceeded if surface decoration with subwavelength structures is employed. − Various light trapping mechanisms were identified to produce broadband absorption enhancement of the sun power with surface subwavelength arrays: low optical impedance using arrays of nanocones and black silicon, − forward scattering by surface Mie resonators, increase in local density of states, excitations of Bloch modes, light trapping driven by light concentration and the utilization of nanolenses and light funnels, − excitations of localized Mie resonances, ,, and so forth.…”

Design of graphene-like nanowall arrays and their optical absorption properties

“…To make the material absorb optical waves efficiently, people often adopt different incident coupling methods or introduce special structures into the material to affect the distribution of the electric field inside the material and the absorption efficiency of the optical wave to improve the performance of the material. [1][2][3][4][5][6] Since graphene was discovered, 7 2D materials have attracted extensive attention and in-depth research due to their unique structures and excellent performances. However, this attention has mainly focused on the properties of fluorescence emission, [8][9][10] saturation absorption, [11][12][13][14] nonlinear optical response, [15][16][17][18][19][20] and horizontally placed monolayer film form.…”