Different approaches are under elaboration aimed at the cost reduction of solar electricity. 3D penetrating emitter solar cells are expected to offer performance enhancement at lower costs, using low carrier lifetime cheaper silicon. Using laser ablation, we have prepared indium–fluorine–oxide/(n+pp+)Cz-Si/indium–tin–oxide bifacial silicon solar cells with deep (110–120 µm) penetrating V-shaped emitter with aspect ratio of 3–4 (height to half-width of the V-grooves). Compared with the reference cell textured with conventional random pyramids and thus not damaged by laser action, which showed front/rear active area photocurrents of 41.1/33.3 mA cm−2, V-grooved solar cells showed only slightly less front photocurrent of 40.1–40.7 mA cm−2, whereas the superior rear photocurrent of 34.2 mA cm−2. The latter indicates that deep penetrating emitter is especially useful in the case of bifacial solar cells. The best pseudo-efficiency for V-grooved cell of 19.5% with estimated bifaciality of ∼80% was obtained for the cell that has been subjected to the smallest laser action during V-grooving. In addition, ray-tracing model was applied to calculate efficiency of light absorption by a V-grooved silicon solar cell for wavelengths in the range from 400 to 1200 nm. The depth of the grooves was varied from 0.05t to wafer's thickness t. The obtained experimental and computational results confirm that the design of crystalline silicon solar cell based on deep penetrating V-shaped emitter makes possible to obtain high-efficiency solar cells even in the case of low-quality silicon wafers.
Silicon wafer with deep penetrating V-grooved emitter.