SOLAR: Novel Nanomaterials and Mathematical Analysis for Ultra-High Efficiency Photovoltaic Systems: A New Paradigm in Solar Cells

Yale University, New Haven CT

Investigators

Abstract

TECHNICAL SUMMARY: Increasing solar cell efficiency and affordability are critical objectives for achieving energy sustainability. The use of semiconducting nanomaterials paired with organic semiconducting polymers offers promise here, with the possibility to realize cost effective high performance heterojunction devices. Current approaches however are limited by small exciton diffusion lengths and the sub-optimal transport characteristics of the percolated nanomaterial aggregates found in today?s state of the art devices. Overcoming these limitations can lead to significant breakthroughs in solar cell performance. This proposal aims to address the above mentioned limitations. The proposed work is a 3-year project that focuses on the synthesis of novel nanomaterials with long excitonic lifetimes such as GaN single walled nanotubes, and the use of well aligned self-assembled mesophases as templates for the directed assembly of these novel nanomaterials. Assembly of anisotropic nanomaterials in nm-spaced arrays will provide significantly increased photo-induced charge transfer by providing electron-hole dissociation surfaces of high, controllable periodicity, separated by length scales that are smaller than the exciton diffusion length itself. . Dissociation at these aligned surfaces provides direct electron conduction pathways to the external electrodes of the device. The organization of this high surface area for exciton dissociation will be accomplished using methods that are scalable and do not require advanced lithography. Harmonic analysis will be leveraged to considerably enhance both ab initio calculations of the electro-optical properties of novel nanomaterials and design of experiments in the multi-parameter space that correlates photo-voltaic performance with material composition and device assembly. NON TECHNICAL SUMMARY: The proposed work will provide the design basis for clean and sustainable energy generation. Successfully executed, it will result in new materials and processes enabling higher efficiency and more cost-effective solar cells. This project has a broad technical impact as the materials and methods developed during the course of the basic research can be applied in other areas such as thermoelectric energy harvesting, light emitting diodes, photodetectors and advanced chemical separations. A number of educational and outreach activities have been integrated into the proposed work. These include a research seminar program run in partnership with three undergraduate focused institutions, recruitment of students, especially from underrepresented groups, for summer research projects and the creation of a new module on experimental design for the introductory undergraduate Chemical Engineering course at Yale University. The impacts of the proposed research overall are: (1) Development of new science that will drive transformative advances in solar technology (2) Development of materials and methods with a broad range of technological relevance beyond photovoltaics (3) Highly interdisciplinary training of graduate students and researchers cutting across chemistry, materials science and mathematics (4) Involvement and mentoring of undergraduate students in research (5) Recruitment of underrepresented groups to science.