Fullerene Aggregation in Thin Films of Polymer Blends for Solar Cell Applications

Abstract

We report on the effects of the film morphology on the fluorescence spectra for a thin film including a quinoxaline-based co-polymer (TQ1) and a fullerene derivative ([6,6]-phenyl-C71-butyric acid methyl ester—PC70BM). The ratio between the polymer and the fullerene derivative, as well as the processing solvent, were varied. Besides the main emission peak at 700 nm in the fluorescence spectra of thin films of this phase-separated blend, a broad emission band is observed with a maximum at 520–550 nm. The intensity of this emission band decreases with an increasing degree of mixing in the film and becomes most prominent in thicker films, films with high PC70BM content, and films that were spin-coated from solvents with lower PC70BM solubility. We assign this emission band to aggregated PC70BM.

The formation of self-assembled structures of C60 in solution and in the volume of an evaporating drop of a colloidal solution

“…In a number of pure and mixed organic solvents, fullerene С n (n = 60, 70, 76, …) molecules show a pronounced tendency to self-assembly and the formation of fairly large functional fullerene aggregates of various shapes and sizes. The problem was fundamentally studied by different physical and chemical methods in [3][4][5][6][7][8][9][10][11] and the obtained results provided a vector toward potential applications in material chemistry [12,13], biomedicine [14][15][16], phototherapy [17][18][19], molecular electronics [20], optoelectronics [21,22] and solar energy [23][24][25].…”

Using Solubility Parameters to Model More Environmentally Friendly Solvent Blends for Organic Solar Cell Active Layers

“…An advance in the field of organic solar cells (OSCs) is of increasing interest, both from a fundamental and an applied point of view, as OSCs offer broad opportunities to produce electricity in a sustainable way as well as showing multiple technical benefits, e.g., solution processability, flexibility, and light-weight [1,2,3,4,5,6]. The commercialization of OSC technology will depend on three key factors: Device efficiency, lifetime, and cost [7].…”

An experimental setup for dip-coating of thin films for organic solar cells under microgravity conditions

“…This field has gained much attention as it promises low-cost, flexible, and aesthetically pleasing solar energy harvesting devices. [1][2][3][4][5][6] Solution processability of materials allows, for example, the possibility to use roll-to-roll printing adapted from the printing industry for the large-scale production of organic solar cells. 7 OSCs are multilayered semiconducting devices, 8,9 consisting of a photoactive layer between two electrodes.…”

“…We have shown that the equipment can be used to prepare thin films of polymer blends from solution in a safe and reliable way under microgravity conditions. We used a well-studied model system 1,14,[24][25][26] The results presented here show that the custom-designed equipment works as intended and that the dip-coated films can be produced under microgravity conditions. This also shows the possibility to transfer OSC production from Earth conditions to space conditions, a research field that presently is at an early stage with, to our knowledge, only two reports on exploring the use of OSCs in space applications.…”