Luminescent downshifting silicon quantum dots for performance enhancement of polycrystalline silicon solar cells

Silicon quantum dots (Si-QDs) with luminescent downshifting properties have been used for the efficiency enhancement of solar cells. In this study, Phenylacetylene-capped silicon quantum dots (PA Si-QDs) have been fabricated and applied as luminescent downshifting material on polycrystalline silicon solar cells, by dropcasting. The PA Si-QD coated solar cell samples presented an average increase in the short circuit current (Isc) of 0.75% and 1.06% for depositions of 0.15 mg and 0.01 mg on 39 mm × 39 mm pc-Si solar cells, respectively. The increase was further enhanced by full encapsulation of the sample leading to overall improved performance of about 3.4% in terms of Isc and 4.1% in terms of power output (Pm) when compared to the performance of fully encapsulated reference samples. The PA Si-QD coating achieved a reduction in specular reflectance at 377 nm of 61.8%, and in diffuse reflectance of 44.4%. The increase observed in the Isc and Pm is a promising indicator for the use of PA Si-QDs as luminescent downshifting material to improve the power conversion efficiency of pc-Si solar cells.