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Abstract
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Morphological, electrochemical, and photovoltaic stabilities of the poly[benzodithiophene-bis(decyltetradecylthien) naphthothiadiazole] (PBDT-DTNT):phenyl-C61-butyric acid methyl ester (PC71BM) solar cells were
promoted by the pre-designed supramolecules on the basis of reduced graphene oxide (rGO) nanosheets.
Nanostructures consisted of the pristine rGO, grafted-rGO/PBDT-DTNT, rGO-polythiophene (GPTh) electrospun
nanofber, grafted-rGO/PBDT-DTNT electrospun nanofber and rGO/PBDT-DTNT samples. The reduction in
photovoltaic characteristics during air aging was the steepest for the unmodifed PBDT-DTNT:PC71BM solar
cells. From rGO based photovoltaics towards the rGO/PBDT-DTNT modifed ones possessing the well-patterned
PBDT-DTNT nanofbers, the slopes of graphs decreased. The most stabilized devices were fabricated on the basis
of PBDT-DTNT:PC71BM:rGO/PBDT-DTNT active layers (power conversion efciency (PCE) from 6.09% for
upon-fabricated to 4.87% for 1 month aged systems) for having the most red-shifted and intensifed absorbance,
the largest phase separation, the lowest impedance responses and the highest photovoltaic characteristics during
1 month air aging (short circuit current density (Jsc) of 12.09 mA/cm2, fll factor (FF) of 63%, open circuit
voltage (Voc) of 0.64 V, hole mobility (µh) of 5.3 × 10–5 cm2/V s, electron mobility (µe) of 7.9 × 10–4 cm2/V s,
charge transfer resistance (Rtr) of 431 Ω cm2 and PCE of 4.87%). The GPTh/PBDT-DTNT/PC71BM
(Jsc = 10.31 mA/cm2, FF = 49%, Voc = 0.55 V, Rtr = 796 Ω cm2 and PCE = 2.78%) and grafted-rGO/PBDTDTNT/PBDT-DTNT (Jsc = 10.98 mA/cm2, FF = 56%, Voc = 0.60 V, Rtr = 539 Ω cm2 and PCE = 3.69%)
electrospun nanofbers also imparted the stabilization of devices within 1 month.
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