Electricity from photovoltaic solar cells: Flat-Plate Solar Array Project final report. Volume IV: High-efficiency solar cells

Abstract

The Flat-Plate Solar Array (FSA) Project, funded by the U.S. Government and managed by the Jet Propulsion Laboratory, was formed in 1975 to develop the module/array technology needed to attain widespread terrestrial use of photovoltaics by 1985. To accomplish this, the FSA Project established and managed an Industry, University, and Federal Government Team to perform the needed research and development (R&D). The High-Efficiency Solar Cells Task was assigned the objective of understanding and developing high-efficiency solar cell devices that would meet the cost and performance goals of the FSA Project. The need for research dealing with high efficiency devices was considered important because of the role efficiency plays in reducing the price per watt of generated energy. This document is a summary of the R&D efforts conducted during the period 1982 to 1986 to provide understanding and control of energy conversion losses associated with crystalline-silicon solar cells. New levels of conversion efficiency (greater than 20 %) were demonstrated. Major contributions were made both to the understanding and reduction of bulk and surface losses in solar cells. For example, oxides, nitrides, and polysilicon were all shown to be potentially useful surface passivants. Improvements in measurement techniques were made and Auger coefficients and spectral absorption data were obtained for unique types of silicon sheet. New modeling software was developed including a program to optimize a device design based on input characteristics of a cell. Although considerable progress was made in this Task, several elements of research were incomplete at the conclusion of the Project.