CAREER: Finite-Absorption-Bandwidth Nanomaterials for Multijunction Photovoltaics and Narrow-Band Photodetectors

Johns Hopkins University, Baltimore MD

Investigators

Abstract

CAREER: Finite-Absorption-Bandwidth Nanomaterials for Multijunction Photovoltaics and Narrow-Band Photodetectors ECCS #1846239; PI: Susanna Thon Nontechnical: The color of materials used in devices such as light sensors and solar cells is important because color determines how these devices respond to incident light. There is a lack of natural materials that only absorb invisible infrared light. This problem limits the efficiency of next-generation solar cells and infrared light sensors. This project addresses this problem by artificially structuring light-absorbing materials on the nanometer scale to control their color. These new materials will be used to make high-efficiency solar cells and color-selective light sensors. The insights and new technologies developed through this project could have wide-ranging applications. Areas that could be impacted include sustainable energy harvesting, hazardous gas sensing, night vision systems, and biomedical imaging. The research activities will be integrated with interdisciplinary educational and outreach activities. These include curriculum development for undergraduate and graduate level classes on nanotechnology and renewable energy. Research team members will also serve as STEM mentors for elementary school students in Baltimore City public schools. Technical: The objectives of the proposed research are to design and build new color-tuned nanomaterials with finite-absorption-bandwidths (FABs) based on photonic band engineering in strongly absorbing materials and use them to make cost-effective multijunction solar cells and narrow-band photodetectors. The proposed research aims to solve the problem of a lack of infrared (IR) optical materials with spectral absorption and transmission profiles that can be independently controlled through the development of new FAB materials composed of colloidal quantum dot thin films for IR responsivity and photonic structuring for visible transparency via control of the in-plane photonic band structure. Methods to be employed include electromagnetic simulations, chemical synthesis, solution-processed device fabrication, and optoelectronic device characterization. The main goals of the project are to (1) establish a quantitative theory for how photonic band structure depends on material absorption using electromagnetic simulations and coupled oscillator theory, (2) build FAB materials using photonic band engineering and self-assembled fabrication techniques, and (3) use the FAB materials to build multijunction solar cells and narrow-band IR photodetectors. If successful, the proposed work will result in a new method for improving the efficiency of current solar cell and photodetector technology by introducing a new class of optoelectronically-active materials that absorb only in the infrared. The project seeks to advance the understanding of fundamental energy transfer processes in nanostructured materials on multiple length scales and use emergent bulk effects to build new optoelectronic devices. These new insights and devices have the potential to enable research in other fields where photoactive materials with controllable spectral profiles could be used for lighting, sensing, and imaging applications, e.g. In addition to the experimental work, the goal of providing a theoretical and computational underpinning for understanding materials behavior on multiple length scales should broaden materials and device research in general by adding to the toolbox of materials and effects that can be exploited for novel applications. The integrated educational and outreach components of the project are designed to engage elementary, undergraduate, and graduate students in the fields of nanotechnology and engineering. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.