Aggregation Controlled Charge Generation in Fullerene Based Bulk Heterojunction Polymer Solar Cells: Effect of Additive

Abstract

Optimization of charge generation in polymer blends is crucial for the fabrication of highly efficient polymer solar cells. While the impacts of the polymer chemical structure, energy alignment, and interface on charge generation have been well studied, not much is known about the impact of polymer aggregation on charge generation. Here, we studied the impact of aggregation on charge generation using transient absorption spectroscopy, neutron scattering, and atomic force microscopy. Our measurements indicate that the 1,8-diiodooctane additive can change the aggregation behavior of poly(benzodithiophene-alt-dithienyl difluorobenzotriazole (PBnDT-FTAZ) and phenyl-C61-butyric acid methyl ester (PCBM)polymer blends and impact the charge generation process. Our observations show that the charge generation can be optimized by tuning the aggregation in polymer blends, which can be beneficial for the design of highly efficient fullerene-based organic photovoltaic devices.

Investigation of Dye Dopant Influence on Electrooptical and Morphology Properties of Polymeric Acceptor Matrix Dedicated for Ternary Organic Solar Cells

“…Strong inhomogeneities and emerging spherical formation can be seen. It can be concluded that in the case of D131, D149 and D358 substances we obtain a mixture in which the second donor is embedded in the donor, both donors are distributed in the acceptor [ 33 , 34 , 35 ].…”

Impact of packing arrangement on the optical properties of C60 cluster aggregates

“…Materials made from organic π -conjugated molecules (for instance, fullerenes and their derivatives) 1–3 have attracted much attention over the past few years as the active components in optoelectronic devices including field-effect transistors, solar cells, and light-emitting diodes, to mention a few examples. Among fullerenes, C60 buckminsterfullerene has attracted much attention due to its application in new bulk heterojunction organic solar cells 4–15 due to the unique properties, including high electron mobility, suitable band gaps, and good compatibility with other semiconducting materials. In a related context, optical excitations in π -conjugated molecules depend strongly on the packing configuration of the basic building blocks.…”

Photophysical Properties of BODIPY Derivatives for the Implementation of Organic Solar Cells: A Computational Approach

“…During the past two decades, organic solar cells have attracted much attention due to their quick improvement of photovoltaic properties and environmental and economic advantages; these include low-cost fabrication, lightweight, mechanical flexibility, high versatility due to applications in many fields, and the simplicity of the synthesis process. − The improvement of organic materials’ photophysical capabilities of a new hole transporting material (HTM) and electron transporting material (ETM), which constitute the photoactive components in organic photovoltaic (OPV) cell devices, can increase the performance of such solar energy conversion materials. − Thus, BODIPY–fullerene derivative synthesis becomes a valuable alternative to compose hole and electron transporting materials. This is so, since, as an acceptor component, the fullerene promotes the presence of many closely spaced electronic levels and a high degree of delocalized charge within an extended π-conjugated structure, as well as a low reorganization energy, making these molecular assemblies ideal for acting as electron transporting materials in the charge-separation state. − …”