Bulk Heterostructure Solar Cells: Electronic Structure and Interface Design

University Of South Florida, Tampa FL

Investigators

Abstract

Technical: The main focus of this research project is on the determination of the electronic structure of three-dimensional heterostructure excitonic solar cells based on blends and thin films of nanoparticles, polymers, dyes and small molecular materials. Such solar cells promise low production costs, while offering low weight and mechanical flexibility. The electronic structure of materials interfaces in the solar cells is crucial for exciton dissociation, recombination prevention, and charge transfer. In order to further increase efficiency and open circuit voltage, it is essential to understand the electronic structure of these interfaces. The main analytical techniques employed in this project include photoemission and inverse photoemission spectroscopies, which allow the direct measurement of charge injection barriers at molecular heterointerfaces. The enabling preparative technique for these experiments is in-vacuum electrospray deposition, which has been established in recent years through previous efforts in the PI's group. This unique combination of photoemission spectroscopy, inverse photoemission spectroscopy, and electrospray deposition in the same experimental system allows the characterization of occupied and unoccupied states at macro-molecular interfaces at the same time. Additionally, feasibility of spray-based fabrication of solar cell structures using the electrospray deposition at atmospheric pressure is investigated in this project. The electrostatics offers ways for controlling the microscopic morphology of deposited films. Non-technical: The project addresses basic research issues in a topical area of materials science with high technological relevance. The research project aims to improve the understanding of heterojunction solar cells based on organic materials and nanoparticles and at the same time seeks a new method for solar cell fabrication. On the educational side, graduate and undergraduate students are trained while participating in the cutting-edge scientific research of a strategically important area. The PI especially focuses on recruiting minority and female students for this research project and has an established record of involving undergraduate students, including those from the underrepresented groups, in research.