Silicon quantum dot solar cell using top-down approach

The current trend of research in the area of third-generation photovoltaics is to increase the efficiency of solar cell device adopting alternate and novel ways such as use of quantum dots to absorb maximum solar spectrum. A new and low-cost top-down approach to fabricate silicon quantum dot solar cell (QDSC) using spin coating of Si QDs embedded in flowable oxide is proposed. Si QDs with diameter smaller than 8 nm were synthesized using topdown approach by ultrasonication of freestanding porous silicon films obtained by anodization of Si. Systematic measurements of current density–voltage (J–V), capacitance–voltage (C–V) and external quantum efficiency (EQE) were carried out. The QDSC exhibits photovoltaic effect, hysteresis in C–V characteristics and improved EQE performance in short wavelength as compared with a reference c-Si cell with same structure, but without QD layer. The novelty and simplicity of the QDSC fabrication process make these results important.