| 초록 |
Edge-selectively halogenated graphene nanoplatelets (XGnPs, X=Cl, Br, and I) for high performance dye-snesitized solar cells (DSSCs) were prepared by the mechanochemically driven reaction between graphite and diatomic halogen molecules (Cl2, Br2 or I2). The contents of halogens (Cl, Br, and I) in XGnPs were 3.18, 1.77, and 0.66 at.%, respectively, by X-ray photoelectron spectroscopy. The XGnPs as counter electrodes (CEs) showed remarkably enhanced electrocatalytic activities toward Co(bpy)33+ reduction reaction in dye-sensitized solar cells (DSSCs) with an excellent electrochemical stability. Amongst XGnPs, IGnP-CE demonstrated the lowest charge-transfer resistance (Rct) of 0.46 Ω cm2 at the CE/electrolyte interface. This value is much lower than that of Pt-CE (0.81 Ω cm2). In addition, the DSSC with IGnP-CE had the highest fill factor (71.3%) and cell efficiency (10.42%), whereas those of DSSCs with Pt-CE were only 70.0% and 10.01%, respectively. |
