SOLAR: Development Methods to Predict Phase Separation and Charge Transport in Bulk Heterojunction Conjugated Polymer Solar Cells

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

TECHNICAL SUMMARY: One of the most important scientific challenges is how to efficiently harvest, convert, store and utilize solar energy. In recent years, there has been a growing interest of developing organic materials for solar cell applications. Organic solar cells offer a low-cost, large-area, flexible, light-weight, clean, and quiet alternative energy source for both indoor and outdoor applications. However, their power conversion efficiencies and operational lifetimes must be improved to enable large-scale commercialization and implementation and deep societal impact. Thus, there is an urgent need to understand fundamental processes in these devices. Currently, the synthesis and optimization of new materials is time consuming and labor intensive, and relies on trial and error approaches with poor success rates. There is therefore a great need to rationally anticipate materials performance from their chemical composition and bulk morphology to accelerate technology development and depart from empirical optimization. The goal of this interdisciplinary program is to mesh complementary expertise in chemistry, materials, physics, and mathematics, to make breakthroughs in the science and technology of organic solar cells. The team will address: 1) the development of new methods to simulate phase separation in BHJ solar cells; 2) the development of first-principles methods to predict carrier mobilities in organic semiconductors; 3) the nanoscale characterization of donor-acceptor interpenetrating networks; 4) the understanding of charge generation and transport process; 5) the synthesis of new conjugated polymers guided by the theoretical predictions; 6) evaluation of materials performance. The simulation methods will be validated extensively on well-studied materials and will then be capitalized for the design of more efficient new materials. As well-orchestrated theoretical and experimental efforts, the project strives to achieve transformative breakthroughs for the development of high-efficiency and low-cost organic solar cells. NON-TECHNICAL SUMMARY: The world demand for energy is expected to double by 2050. As of now, there is no viable technology to address this challenge without emission of carbon dioxide to the environment. In view of this, increasing the power conversion efficiency and operational lifetime of plastic solar cells is provides the opportunity to create a clean and potentially economically viable energy source with a wide range of applications. The goal of the proposed research is to assemble the team of scientists with complementary expertise in chemistry, materials, physics, and mathematics, to establish theoretical guidelines for a rational development of materials and solar cell device structures. Successful completion of the program is expected to relieve the current need to optimize device performance via trial and error procedures and will pave the way for an acceleration of technical innovation. This project integrates interdisciplinary research and education by involving the participation of undergraduate and graduate students and postdoctoral researchers, with special emphasis in the recruitment of underrepresented students. New courses on organic semiconductors and their applications in energy conversion will be offered at UCSB. The courses will be taught in an interdisciplinary environment, with which the investigators hope to address the urgent need to train researchers in the area of renewable energies. Furthermore, Workshops and demonstrations on solar energy for K-12 students, teachers, and parents in local schools will be developed to create awareness about renewable and sustainable energy sources. In addition, by exposing students to these ideas at such an early stage, the investigators hope to awaken in them the desire to pursue a career in sciences.