Enhancing the Power Conversion Efficiency of Inverted Organic Photovoltaics with Gold Functionalized Reduced Graphene Ox

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Enhancing the Power Conversion Efficiency of Inverted Organic Photovoltaics with Gold Functionalized Reduced Graphene Oxide Rebecca Isseroff1, Zhenhua Yang1, Jessica Kim2, Andrew Chen3, Miriam Rafailovich1 1 Dept. of Materials Science and Engineering, SUNY Stony Brook, Stony Brook, NY 11794, United States 2 Manhasset High School, Manhasset NY 11030, United States 3 Rice University, Houston, TX 77251, United States ABSTRACT In this study, an “inverted” design, phase-separated morphology and gold-functionalized reduced graphene oxide (Au-rGO) were used to address exciton recombination and poor Fermi level alignment. To increase efficiencies, a unique methodology was used to coat Au-rGO on top of the active layer. When 0.05 Au-rGO was blended with the active layer, there were metalthiolate bonds with P3HT and π-π stacking with PCBM. However, KPFM, measured for the first time for this material, showed that the while 0.05mM Au-rGO reduced the energy gap between P3HT and PBCM, this was offset by recombination. KPFM showed that Au-rGO may be better suited between the active layer and electrode. When 0.5mM Au-rGO was coated on top of the active layer, efficiency increased (p0.999) in PCE from the control because while its relative potential was lower than that of P3HT, the difference (126mV) may have been too great to reduce the energy gap between the HOMO of P3HT and the work function of silver. 0.5mM Au-rGO significantly increased (p