Advanced light trapping designs for high efficiency thin film silicon solar cells

On the potential of light trapping in multiscale textured thin film solar cells

“…For the multiscale textured substrates, the glass substrate is modeled by hexagonally arranged concave craters. The surface morphology of FTCO layer is determined by the surface coverage algorithm [25,26] because the growth of the ZnO:B film deposited by LPCVD process takes place in the direction of local surface normal [27]. The resulting microtextures of the FTCO layer have diameters of almost 3 mm and height of 1.2 mm.…”

“…Optical simulations of solar cells with different back reflector morphologies show that a smoothening of the back reflector leads to a drop of the optical losses of the back reflector and an increase of the quantum efficiency [8,13]. In this study, we have assumed that the ZnO buffer layer is prepared by LPCVD process, so that the film grows in the direction of the local surface normal [27]. In these simulations, the nominal thickness of ZnO buffer layer is increased from 0 nm to 400 nm, while the formation of LPCVD ZnO nanopyramids is neglected.…”

Plasma Textured Glass Surface Morphologies for Amorphous Silicon Thin Film Solar Cells-A review

“…The front transparent conductive oxide (TCO) films must exhibit good transparency, low resistivity and excellent light scattering properties for high efficiency a-Si TFSCs. Various textured TCO films like SnO 2 :F, ZnO:Al, and ZnO:B are commonly used as substrates to increase the light path within the absorber layer for the enhancement of light trapping in the solar cell [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. However, these textured TCOs substrates are insufficient to gain the light scattering effect needed for longer wavelength region due to their smaller (~600 nm) textured size features.…”

“…Various methods to create textured glass surface morphologies have been investigated in recent years like sand blasting, powder blasting, wet chemical etching with hydrofluoric acid (HF) based solutions, aluminum induced texturization (AIT) and plasma etching through a nanostructured metal mask [11][12][13][14][15][16]. Thus, the textured glass surface substrates with nano-and micro size features can be employed to scatter light in lower as well as in longer wavelength region.…”

The role of front and back electrodes in parasitic absorption in thin-film solar cells

“…For this device, light trapping strategies are applied for a broad wavelength range of the solar spectrum, covering the near infrared (NIR) range between 600 nm and 1100 nm. The absorption coefficient of µc-Si:H silicon being weak in the NIR, efficient light trapping (typically via nanotextured interfaces) is mandatory to achieve large currents [7][8][9][10][11][12][13][14]. Yet, in the presence of a very efficient light-trapping scheme, parasitic absorption (A P ) due to the non-photoactive layers (such as the doped layers, the electrodes and the back a e-mail: mathieu.boccard@epfl.ch reflector) is also increased compared to a flat cell configuration [6,[15][16][17].…”