Hole Transfer Promoted by a Viscosity Additive in an All-Polymer Photovoltaic Blend

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Viscosity modifiers are crucial for enhancing the mechanical flexibility of organic optoelectronic devices.
• The impact of these additives on charge dynamics, essential for device efficiency, is not well understood.

Purpose of the Study:

• To investigate the effects of a high-viscosity polymeric additive on electron and hole transfer dynamics in all-polymer organic photovoltaic blends.
• To elucidate the underlying mechanism responsible for observed changes in charge transfer.

Main Methods:

• Ultrafast transient absorption spectroscopy was employed to monitor charge transfer processes.
• All-polymer organic photovoltaic blends with and without viscosity modifiers were analyzed.

Main Results:

• Hole transfer from charge-transfer excitations in the acceptor was significantly promoted by the viscosity additive.
• Electron transfer from local excitations in the donor remained largely unaffected.
• The observed effects were attributed to modifications in the dielectric screening of the blend.

Conclusions:

• Viscosity modifiers can selectively influence charge transfer dynamics in organic photovoltaic blends.
• Modulating the dielectric environment offers a novel strategy for optimizing the performance of flexible organic solar cells.