Hexagonal sphere gratings for enhanced light trapping in crystalline silicon solar cells

Abstract

Enhanced absorption of near infrared light in silicon solar cells is important for achieving high conversion efficiencies while reducing the solar cell's thickness. Hexagonal gratings on the rear side of solar cells can achieve such absorption enhancement. Our wave optical simulations show photocurrent density gains of up to 3 mA/cm2 for solar cells with a thickness of 40 µm and a planar front side. Hexagonal sphere gratings have been fabricated and optical measurements confirm the predicted absorption enhancement. The measured absorption enhancement corresponds to a photocurrent density gain of 1.04 mA/cm2 for planar wafers with a thickness of 250 µm and 1.49 mA/cm2 for 100 µm.

CH_3NH_3PbI_3 perovskite / silicon tandem solar cells: characterization based optical simulations

“…Our flat SHJ cell model therefore features a planar front surface, but still exhibits excellent light trapping properties, without the anti-reflection effect of the front side texture. In practice, planar front surface cells with ~100 µm thick absorbers and enhanced light path length, can be realized with structured rear surfaces, for example by using hexagonal sphere gratings [38]. For anti-reflection properties due to a texture, see the section on surface texture effects.…”

Rear side sphere gratings for improved light trapping in crystalline silicon single junction and silicon-based tandem solar cells

“…The refractive index contrast between the spheres and the matrix material creates a diffractive structure. Absorption enhancement in crystalline silicon wafers due to a sphere grating has already been reported [23]. In this work, we integrate the sphere gratings into fully processed silicon solar cells.…”

“…Following deposition, the samples are annealed in a tube furnace at 800°C. The fabrication of the sphere grating has been done similar to [23,27]. For this work we adapted the sphere grating fabrication for the TOPCon surface.…”

Efficiency increase of crystalline silicon solar cells with nanoimprinted rear side gratings for enhanced light trapping

“…[17][18][19][20][21]), many works on diffractive rear side structures for wafer based crystalline silicon solar cells focused on theoretical investigations and optical measurements only (e.g. [22][23][24][25][26][27][28][29]). Peters et al predicted a photocurrent density gain of up to 1.8 mA/cm 2 for a linear grating optimized with respect to period and depth and 40 mm thick substrates based on wave-optical simulations [22].…”