Application of microcrystalline Si<inf>1&#x2212;x</inf>Ge<inf>x</inf> infrared absorbers in triple junction solar cells

Understanding the nano-photonics absorption limit in both front-side and front/rear-side textured slabs

“…Therefore, a significant amount of research has been dedicated to different light management techniques, in order to improve light absorption in the device active layer [2,3]. Light management is mostly focused on (i) the effective use of solar spectrum [4][5][6][7][8][9][10], (ii) maximizing the number of photons reaching the absorber layer [11][12][13][14], (iii) keeping the solar radiation energy inside the absorber long enough, until it is absorbed by the material. The first aspect can be achieved by employing spectrum splitters and multi-junction devices [15][16][17][18].…”

Hydrogenated microcrystalline silicon germanium as bottom sub-cell absorber for triple junction solar cell

“…In recent years, mc-Si 1−x Ge x :H, which exhibits narrower variable band gap and higher absorption coefficient, has attracted much attention for the use as the bottom sub-cell i-layer and been expected to have a better photoresponse in the long-wavelength region compared with mc-Si:H [6][7][8][9][10][11]. In addition, promising experimental results of single junction and multi-junction solar cells using mc-Si 1−x Ge x :H intrinsic layers have already been reported [12][13][14].…”

Numerical simulation of a triple-junction thin-film solar cell based on μc-Si1−xGex:H

“…As a solution to this problem, µc-Si 1−x Ge x :H alloys have been proposed as the absorber of the bottom cell by Kondo et al, [6] which have been proved to possess high absorption coefficients in the whole solar spectrum compared with µc-Si:H and have a tunable bandgap in a range from 0.67 V to 1.1 V as the ratio of Ge to Si changes, and therefore it could extend the absorption scope into a longer wavelength region. Recently, they have obtained an initial efficiency of 11.6% in a structure of a-Si:H/µc-Si:H/µc-Si 0.9 Ge 0.1 :H. [7] However, in their triplejunction solar cell structure, the middle cell is fixed as µc-Si:H, which will restrict the potential of the bandgap combination. As a consequence, our group proposes a new kind of triplejunction structure: a-Si:H/a-SiGe:H/µc-SiGe:H, in which we can find the preferred bandgap configuration by modulating the bandgaps of the middle and bottom cells and achieve better utilization of the solar spectroscopy.…”