Solar energy conversion plays a very important role in the rapid introduction of renewable energy, which is essential to meet future energy demands without further polluting the environment, but current solar panels based on silicon are expensive due to the cost of raw materials and high energy consumption during production. The way forward is to move towards thin-film solar cells using alternative materials and low-cost manufacturing methods. The photovoltaic community is actively researching thin-film solar cells based on amorphous silicon, cadmium telluride (CdTe), copper indium gallium diselenide (CIGS), and dye-sensitised and organic materials. However, progress has been slow due to a lack of proper understanding of the physics behind these devices.
This book concentrates on the latest developments and attempts to improve our understanding of solid-state device physics. The material presented is mainly experimental and based on CdTe thin-film solar cells. The author extends these new findings to CIGS thin-film solar cells and presents a new device design based on graded bandgap multi-layer solar cells. This design has been experimentally tested using the well-researched GaAs/AlGaAs system, and initial devices have shown impressive device parameters. These devices are capable of absorbing all radiation (UV, visible and infra-red) within the solar spectrum and combine "impact ionisation" and "impurity photovoltaic" effects.
The improved device understanding presented in this book should impact and guide future photovoltaic device development and low-cost thin-film solar panel manufacture. This new edition features an additional chapter besides exercises and their solutions, which will be useful for academics teaching in this field.
I. M. Dharmadasa is professor of applied physics and leads the Electronic Materials and Sensors Group at Sheffield Hallam University, UK. He has worked in semiconductor research since becoming a PhD student at Durham University as a Commonwealth Scholar in 1977, under the supervision of the late Sir Gareth Roberts. His interest in the electrodeposition of thin-film solar cells grew when he joined the Apollo Project at BP Solar in 1988. He has continued this area of research on joining Sheffield Hallam University in 1990.
Photovoltaic Solar Energy Conversion. Status Report on Solar Energy Technologies. Electrochemical Deposition of Solar Energy Materials. Background of the CdTe Solar Cell and the New Device Concept. Extension of the New Model to CIGS Thin-Film Solar Cells. Effective Harvesting of Photons. Multi-layer Graded Bandgap Solar Cells. Solar Cells Active in Complete Darkness. Effects of Defects on Photovoltaic Solar Cell Characteristics. Progress in Development of Graded Bandgap Thin-Film Solar Cells with Electroplated Materials. A Future Dominated by Solar Energy. Is Fermi-Level Pinning Affecting GaAs-Based Solar Cells?. Thoughts on Future Directions of Thin-Film Solar Cell Research and Development