title: A simple strategy for synthesizing highly luminescent carbon nanodots and application as effective down-shifting layers.
abstract: We propose a novel strategy to prepare highly luminescent carbon nanodots (C-dots) by employing a hydrothermal method with citric acid as the carbon source and ethylenediamine as the nitrogen source, together with adding moderate ammonia water (AW) to achieve both appropriate inner structure and excellent N passivation. The effect of pH value and AW amount on the luminescence properties has been thoroughly investigated. The photoluminescence quantum yield of the resultant C-dots reaches as high as 84.8%, which is of 10.56% higher than that of the C-dots synthesized in the absence of AW in the reaction precursors. We have further combined the highest luminescent C-dots with polyvinyl alcohol to form luminescent down-shifting layers on silicon nanowire solar cells. An effective enhancement of short-circuit current density has been realized and the contribution of the down-shifting has been extracted quantitatively from the deterioration of surface reflectance and the gain of the optical absorption redistribution by means of a theoretical model on external quantum efficiency analysis.
authors.affiliation: Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, and Institute of Solar Energy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
authors.forename: Xugen
authors.initials: X
authors.lastname: Han
authors.forename: Sihua
authors.initials: S
authors.lastname: Zhong
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Shen
mesh_terms: D002244:Carbon / Q000737:chemistry*; D006801:Humans; D049449:Luminescence; D049408:Luminescent Agents; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*
chemical_list: D049408:Luminescent Agents; D002244:Carbon