Advanced Solar Cell Polymers that can Multiply the Electrical Output


One challenge in improving the efficiency of solar panels is that certain amount of the absorbed light energy is lost as heat. So scientists are looking to create material that could convert more of the energy into useful electricity.

This multiplication process may be made efficient by the same molecular polymer chain by the two charges on a single molecule means the light-absorbing, energy-producing materials don’t need to be arrayed as perfect crystals to make extra electrical charges. Instead, the self-contained materials work efficiently when dissolved in liquids, which opens for a wide variety of industrial-scale manufacturing processes, including “printing” solar-energy producing material like ink.

The idea of producing two charges from a unit of light is known as “singlet fission.” Fission is the process that splits an individual biological cell into two and results in the multiplication of cells. Devices based on this multiplication concept have the potential to break through the top of the limit on the efficiency of single junction solar panels, which will be currently around 34 percent. The challenges rise above doubling the electrical output of the solar panel materials since these materials should be incorporated into actual current-producing devices. The more efficient current generating materials need to be added to existing solar panel materials and construct new kinds of solar panel designs.

Most singlet fission materials explored till now lead to twin charge carriers being produced on separate molecules. These only work nicely once the material is in a crystalline film with long-range order, where strong coupling results in one more charge being produced on a neighboring molecule. Producing such good quality crystalline films and integrating them with solar panel manufacturing complicates the process.

Producing the twin charges about the same polymer molecule results in a product that is appropriate for a much wider number of industrial processes.

Probably the most fascinating area of the interdisciplinary project is exploring the electronic and chemical requirements that enable this multiplication process to happen efficiently.

Information on the materials analysis

The scientists used time-resolved optical spectroscopy to induce and quantify singlet fission in the different polymer compositions employing a single laser photon.

When the laser pulse of light energy is appliedĀ to a product and compared to that energy using some weaker light pulses, somewhat analogous to taking snapshots employing a camera with a quick shutter appears.

Another step is to test a sizable class of materials utilizing the design framework they’ve identified, and then integrate many of these carbon-based polymer materials into functioning solar cells.

Another challenge is to harness the excess excitations within an operating device. This might be in conventional bulk type solar panels, or in third-generation concepts centered on another inorganic (non-carbon) nanomaterials. The dream is to construct hot-carrier solar panels that may be fully assembled using solution processing of organic singlet fission materials.