The sun represents the most abundant potential source of pollution-free energy on earth. Solar cells for producing electricity require materials that absorb the sun?s energy and convert its photons to electrons, a process called photovoltaics. The search for the best photovoltaic material is an active area of solar cell research. Recently, an exciting new class of photovoltaic materials called organo-metal perovskites has emerged. These materials are promising because they have low production cost, use elements and materials abundant in the earth's crust, and currently possess solar energy conversion efficiencies of over 15%. However, the reasons why these materials work so well is not really known. The overall goal of this project is to gain a fundamental understanding of the origins of photovoltaic performance in perovskite based solar cell materials by using highly sensitive techniques to probe the material surfaces and interfaces without destroying the material itself. This fundamental understanding can be used to advance the development of perovskite materials for solar cell applications. The project activities will train graduate and undergraduate students in state of the art techniques for surface characterization of materials. Existing programs at the University of Rochester will be used to provide lab tours, short lectures, and hand-on experiences for high school girls in organic electronics to stimulate interest in STEM fields. Robust perovskite solar cell demonstration kits will be developed for use by high school students.
Recently, organo-metal perovskites have emerged as an exciting new class of earth-abundant photovoltaic materials, with solar energy conversion efficiencies exceeding 15% and potential for low manufacturing cost. The overall goal of this project is to use an array of surface analysis tools to gain a fundamental understanding of origins of photovoltaic performance of organometal trihalide perovskite materials. The proposed research will study the electronic structure, interface formation, carrier relaxation dynamics, and factors affecting the stability of these materials in air, through variety of techniques, which include ultraviolet and x-ray photoelectron spectroscopy, inverse photoemission spectroscopy, and time-resolved 2-photon photoemission spectroscopy. The surface structure and morphology will be characterized using low energy electron diffraction, scanning tunneling microscopy and atomic force microscopy. Finally, perovskite thin film device structures will be prepared and characterized in situ under vacuum and then transferred directly to the surface analytical tools to determine how interface structures change. This integrated approach will provide a comprehensive description of the electronic structure and interface properties of perovskite based solar cell materials and their correlation to photovoltaic performance. The project activities will train graduate and undergraduate students in state of the art techniques for surface characterization of materials. Existing programs at the University of Rochester will be used to provide lab tours, short lectures, and hand-on experiences for high school girls in organic electronics to stimulate interest in STEM fields. Robust perovskite solar cell demonstration kits will be developed for use by high school students.
