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Colloidal semiconductor quantum shells for energy conversion applications

Mikhail Zamkov,

Bowling Green State University

Colloidal semiconductor quantum dots have attracted considerable attention in recent decades due to their remarkable optical and electronic properties. Many applications of these nanomaterials have been proposed for the energy sector technologies. However, the practical implementation of quantum dots remains limited by their poor performance under intense optical or electrical excitation. This issue arises from an energy loss mechanism known as Auger recombination, which represents a major performance bottleneck in many quantum dot applications, including photodetectors, scintillators, photovoltaic devices, high-brightness LEDs, and quantum light sources. The present project will address this issue by developing two-dimensional semiconductor quantum shells, which geometry is designed to sustain energetic loads more efficiently than quantum dots. By enabling an optimal distribution of the excitation energy across the nanostructure, quantum shells effectively suppress Auger recombination. It is expected that quantum shells will outperform conventional quantum dots in several demanding technologies, including X-ray detection, light sensing, spin-based LEDs, and optically pumped lasers. These materials also show promise for quantum technologies, where they can efficiently generate pairs of entangled photons. Along these lines, the project will explore three directions that take advantage of the quantum shell design, which include materials for more efficient radiation detection, infrared-sensitive quantum shells for thermal imaging and photodetection, and cubic quantum shells for polarized single-photon generation in quantum-information technologies.

  The successful development of semiconductor quantum shells will establish a new class of colloidal nanomaterials for solution-processed semiconductor devices. Because Auger recombination limits many applications of low-dimensional nanostructures, the ability to control this process is expected to benefit multiple areas of energy science and technology. More broadly, quantum shells could emerge as an alternative to existing colloidal nanomaterials, such as quantum dots, nanosheets, nanotubes, and nanorods, by combining the ability to sustain high energy loading with an improved capacity for assembly into ordered, electrically coupled nanoparticle solids. Ultimately, the quantum shell concept can be extended to non-toxic and earth abundant semiconductor systems for use in printable nanostructured materials. As an integral component of this project, the PI will also lead a multifaceted educational effort focused on student training, research mentorship, and public outreach.