Broadband optical absorption enhancement in stacked MWCNTs array: towards new generation of solar cells

In this paper, we have proposed a new type of multi-layer solar cell structure based on multi-walled carbon nanotube (MWCNT) photonic crystals grown on a silicon substrate. The structure is constructed by stacking layers of MWCNTs array with different lattice constants from 100 to 800 nm as an active layer. It exhibits a remarkable absorption efficiency, reaching a peak value of 92.61% within a broad absorption spectrum spanning from 100 to 2000 nm. The absorption capacity and range are significantly improved compared to conventional solar cell structures. The effect of the filling factor on the absorption coefficient was examined. Various filling factor values ranging from 4 to 60% were evaluated to optimize the structure, with the most favorable outcome observed at a filling factor of f = 30%. The host medium is silicon, which is fully compatible with Si technology, enabling seamless easy integration with other Si-based technology devices.