United States. New nanomaterials developed by researchers at the Advanced Science Research Center (ASRC) at the Graduate Center of the City University of New York (CUNY) could provide a path to more efficient and potentially affordable harvesting of solar energy.
The materials, created by scientists with THE ASRC's Nanoscience Initiative, use a process called singlet fission to produce and extend the lifespan of electrons generated by light.
"We modified some of the molecules in commonly used industrial dyes to create self-assembling materials that facilitate higher performance of extractable electrons and extend the life of electrons in the state, giving us more time to collect them in a solar cell," said Andrew Levine, lead author of the paper and Ph.D. student at the Graduate Center.
The process of self-assembly, Levine explained, causes the dye molecules to stack in a particular way. This stacking allows dyes that have absorbed solar photons to coupl and share energy with, or "excite," neighboring dyes. The electrons in these dyes are then decoupled so that they can be collected as usable solar energy.
Methodology and findings
To develop the materials, the researchers combined several versions of two frequently used industrial dyes: dicetopirrolopirrol (DPP) and rilene. This resulted in the formation of six self-assembling superstructures, which the scientists investigated using electron microscopy and advanced spectroscopy. They found that each combination had subtle differences in geometry that affected the excited states of the dyes, the appearance of singlet fission, and the performance and lifespan of the removable electrons.
Meaning
"This work provides us with a library of nanomaterials that we can study for solar energy," said Professor Adam Braunschweig, principal investigator of the study and associate professor at the ASRC Nanoscience Initiative and the Departments of Chemistry at Hunter College and The Graduate Center. . "Our method of combining dyes into functional materials using self-assembly means we can carefully adjust their properties and increase the efficiency of the critical light collection process."
The materials' ability to self-assemble could also shorten the time to create commercially viable solar cells, the researchers said, and prove more affordable than current manufacturing methods, which rely on the time-consuming molecular synthesis process.
The research team's next challenge is to develop a method to collect the solar charges created by their new nanomaterials. Currently, they are working to design a rilene molecule that can accept the electron from the DPP molecule after the singlet fission process. If successful, these materials would initiate the singlet fission process and facilitate charge transfer to a solar cell.
Source: The Graduate Center of The City University of New York.
