Nanomaterials for solar cells

Harnessing the sunlight incident on earth with inexpensive and efficient solar cells is one of the most important challenges of the twenty-first century. Solar cells made using nanostructured materials (e.g., nanoparticles and nanowires) are being investigated around the world to address this challenge. In this article, Professor Eray Aydil provides specific examples of how nano-solar-cell technology can help address our energy needs. He argues that nanostructured materials such as nanoparticles and nanowires present three unique advantages that can help in solar-to-electric energy conversion. First, he explains that nanomaterials provide large surface and interfacial areas per unit volume, a significant advantage for both light absorption and charge separation, the two critical steps in solar-to-electric energy conversion. Second, he describes how confinement of charge carriers in nanometer size particles provide the ability to tune the optical and electronic properties of materials in ways that are not possible with bulk materials. For example, certain newly discovered quantum mechanical phenomena exist only in nanoparticles and can provide the means to surpass established theoretical efficiency limits. Finally, he predicts that nanostructured materials such as "nanoparticle inks" may help reduce solar cell manufacturing costs by providing the means to mass produce thin films inexpensively through well-established roll-to-roll coating or printing technologies.