Solar cell efficiency improvement employing down-shifting silicon quantum dots

We report the synthesis and characterization of silicon quantum dots (Si-QDs) that exhibit down-shifting, photo-luminescent characteristics, and the dependence of luminescent characteristics on sodium l-ascorbate, APTES and the reaction time. The synthesized silicon nanostructures were observed to absorb UV photons and subsequently reemit in a broad visible region extending from 450 to 650 nm. The incorporation of these nanostructures as a photon down-shifting layer on solar cells triggered improvements in the performance of the fabricated photovoltaic devices, especially in the open circuit voltage (V_oc) and short circuit current density (J_sc). Specifically, the experimental results showed increments in the V_oc from 532.6 to 536.2 mV and in the J_sc from 33.4 to 38.3 mA/cm². The combined effect of those improved V_oc and J_sc values led to an increment in the power conversion efficiency (PCE) from 11.9 to 13.4%. This increment represents an improvement of the order of 12.4% on the power conversion efficiency on the silicon solar cells employed. The observed results could be conducive to promoting the proliferation of photovoltaic structures. Additionally, we discuss the fabrication and characterization of the single crystal Silicon (c-Si) Solar cells employed in this exercise.