چکیده
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The air stability of poly(3-hexylthiophene) (P3HT):phenyl-C71-butyric acid
methyl ester (PC71BM) solar cells and their modified configurations was
investigated by pure carbon nanotube (CNT), CNT-g-poly(3-dodecylthiophene)
(PDDT) (stem)-P3HT (leaf), CNT-g-P3HT/P3HT butterfly, and core (CNT)-
mantle (polyaniline (PANI))-shell (P3HT) nanostructures over a period of
1 month at 5-day intervals. Although the photovoltaic parameters decreased
with aging time, the slopes of the decrease were less steep for well-modified
systems. The slowest decreasing trends in short-circuit current density
(Jsc = 13.41 mA/cm2 to 12.48 mA/cm2), fill factor (FF = 67% to 62%), opencircuit voltage (Voc = 0.69 V to 0.64 V), power conversion efficiency (PCE =
6.20% to 4.95%), and charge transfer resistance (Rtr = 370 X cm2 to
688 X cm2) plots versus aging were found for the core-mantle-shell modified
photovoltaic devices. After 1 month of aging, P3HT:PC71BM:core-mantleshell solar cells performed even better than 5-day-aged P3HT:PC71BM:stemleaf photovoltaics (11.94 mA/cm2, 63%, 0.65 V and 4.89%). Orderly packed pstacks of P3HT backbones in the respective crystals prevented the oxygen and
water from penetrating the crystals, and thus the morphology was more
stable. Pre-developed nanostructures including CNT-g-P3HT/P3HT butterfly
and CNT-g-PANI/P3HT core-mantle-shell supramolecules not only provided
higher phase separation in as-prepared devices, but also controlled and stabilized the morphology and constituent arrangement during air aging processes.
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