Incorporation of a light and carrier collection management nano-element array into superstrate a-Si:H solar cells

Abstract

Superstrate a-Si:H solar cells incorporating a nano-column array for light and photocarrier collection have been fabricated and evaluated. It is found that the short circuit current density (JSC) is significantly increased while the open circuit voltage and fill factor are not detrimentally affected by this architecture. Numerical analysis of JSC matches experiment and shows that the enhanced JSC observed is due to both effective absorber thickness and photonic-plasmonic effects. Further analysis shows that this nano-column architecture can lead to a 42% increase in conversion efficiency over that of the planar control for a 200 nm absorber thickness cell.

Nanoscale Observation of Waveguide Modes Enhancing the Efficiency of Solar Cells

“…Overall, the nanophotonic light trapping improves the short-circuit current density ( J SC ) of our test solar cell from 11.6 to 13.7 mA/cm 2 causing a relative power conversion efficiency η from 7.3% (flat reference solar cell) to 8.4% (nanophotonic solar cell). It shall be noted that several research groups have recently investigated comparable types of nanophotonic solar cells and reported on their remarkable improvements by nanophotonic light management even in comparison to state-of-the-art commercially available random textures. ,,− …”

Influence of film formation on light-trapping properties of randomly textured silicon thin-film solar cells

“…Depending on the configuration of the solar cells, light-trapping is achieved by nanotexturing the front contact (superstrate configuration) or the back contact (substrate configuration). [1][2][3][4][5][6][7][8][9][10] Nanotextures scatter/diffract the light and increase the optical path length and absorption inside the absorber layer of the solar cells. The nanotextures propagate through the deposited layers of the solar cells.…”

“…Consequently, both contacts of the solar cells are textured, but the morphologies of the contacts are different. [3][4][5][6][7][8][9][10][11][12][13][14] The back contact morphology is affected by the formation of the silicon film on the textured substrate. To optimize the light-trapping properties of thin-film solar cells, a detailed understanding of the film formation and the influence of the realistic interface morphologies on the lighttrapping properties is required.…”

“…The approach combines realistic interface morphologies with three-dimensional (3D) finite-difference timedomain (FDTD) simulations. The approach is demonstrated for amorphous silicon solar cells prepared on an Asahi-U substrate, 3,4) but it is also applicable to other substrates such as multiscale textured substrates, 1,15) nanowires, 7,16) or periodically textured substrates. [8][9][10]17) Light-trapping in superstrate configuration solar cells is typically realized using randomly textured transparent conductive oxide (TCO) as a substrate.…”

“…The deposition of low-temperature amorphous silicon solar cells is typically achieved by plasma-enhanced chemical vapor deposition (PECVD). [1][2][3][7][8][9][11][12][13]18) Under standard deposition conditions, it can be assumed that the amorphous silicon film grows in the direction of the local surface normal. On the basis of this approximation, a 3D surface coverage algorithm was developed.…”