Effect of Polymer Aggregation on the Open Circuit Voltage in Organic Photovoltaic Cells: Aggregation-Induced Conjugated Polymer Gel and its Application for Preventing Open Circuit Voltage Drop

Abstract

To investigate the structure-dependent aggregation behavior of conjugated polymers and the effect of aggregation on the device performance of conjugated polymer photovoltaic cells, new conjugated polymers (PVTT and CN-PVTT) having the same regioregularity but different intermolecular packing were prepared and characterized by means of UV-vis spectroscopy and atomic force microscopy (AFM). Photovoltaic devices were prepared with these polymers under different polymer-aggregate conditions. Polymer aggregation induced by thermal annealing increases the short circuit current but provides no advantage in the overall power conversion efficiency because of a decrease in the open circuit voltage. The device fabricated from a pre-aggregated polymer suspension, acquired from ultrasonic agitation of a conjugated polymer gel, showed enhanced performance because of better phase separation and reduced recombination between polymer/PCBM.

Self‐Assembled Gelators for Organic Electronics

“…Because of the better phase separation and reduced recombination between polymer 2 and PCBM, photovoltaic devices fabricated using fibrous aggregates of the ultrasonicated polymer gel containing PCBM exhibited enhanced performance. [23] Interestingly, the polymeric gel fibers exhibited a higher hole mobility and at the same time increased J sc values without change in the V oc values. Hence the fabrication of solar cells using a preassembled polymer gel suspension is a promising tool for increasing the overall power conversion efficiency without decrease in the V oc value.…”

Selbstorganisierte Gelbildner für die organische Elektronik

“…[23] Interessanterweise zeigten die polymeren Gelfasern eine hçhere Lçcherbeweglichkeit und infolgedessen hçhere J sc -Werte bei unveränderten V oc -Werten. Dank einer verbesserten Phasentrennung und verringerten Rekombination zwischen Polymer 2 und PCBM zeigten Solarzellen, die aus faserfçrmigen Aggregaten des ultraschallbehandelten, PCBM enthaltenden Polymergels hergestellt wurden, verbesserte Leistungsmerkmale.…”

“…Dank einer verbesserten Phasentrennung und verringerten Rekombination zwischen Polymer 2 und PCBM zeigten Solarzellen, die aus faserfçrmigen Aggregaten des ultraschallbehandelten, PCBM enthaltenden Polymergels hergestellt wurden, verbesserte Leistungsmerkmale. [23] Interessanterweise zeigten die polymeren Gelfasern eine hçhere Lçcherbeweglichkeit und infolgedessen hçhere J sc -Werte bei unveränderten V oc -Werten. Die Herstellung von Solarzellen unter Verwendung einer vorab aggregierten Polymergelsuspension ist somit eine vielversprechende Methode zur Erhçhung der Energieumwandlungseffizienz, ohne dabei den V oc -Wert zu beeinträchtigen.…”

Efficient Separation of Conjugated Polymers Using a Water Soluble Glycoprotein Matrix: From Fluorescence Materials to Light Emitting Devices

“…Band gap engineering starts from appropriate selection of the conjugated polymer backbone and is further tuned by donor/acceptor substitution, copolymerization or variation of the conjugation length. Evenly important is controlling the aggregation behavior of CPs, which has been extensively studied to optimize the processing conditions in organic electronic device fabrication . In this context, efficient separation of CPs is critical for the construction of multi‐component active layers.…”