This book provides an up-to-date account of exciting developments in thin film inorganic photovoltaic (PV) solar energy. For many years the thin film PV market was led by amorphous silicon and showed the potential for thin film products on glass substrates. This has grown rapidly over the past 10 years with new thin film PV materials going to large volume manufacture such as the polycrystalline thin film PV materials, cadmium telluride and copper indium diselenide. Amorphous silicon has also undergone a transformation with more stable and more efficient multi-junction cells.

The book is very timely because thin film PV is established in the market for large-scale solar energy production but is still small, and arguably in its infancy, compared with the predominant crystalline silicon PV module products. This has generated a wealth of research over the past 10 years to find solutions to challenges such as achieving higher conversion efficiency, greater long-term stability and reduction in manufacturing costs. The latter turns out to be important for materials research as some of the materials currently used in thin film PV might become in short supply in the future and are subject to commodity price fluctuations. For this reason the introduction, Chapter 1, includes an overview of techno-economic considerations that provide a context for the materials challenges covered in this book. The contents give an up-to-date summary of the latest research but also examine some of the fundamental considerations that underpin the technology. The fundamental considerations in thin film PV are covered in Chapter 2 and each of the remaining chapters develops different aspects of these underpinning considerations. The chapters on absorber materials (Chapters 3, 5, 6 and 7) cover materials systems from thin film silicon through to multi-junction III–V devices. There are also chapters common to assisting all the thin film PV materials systems meeting the challenges such as transparent conducting oxides, where in Chapter 4 we have an account of the pioneering work carried out at the US National Renewable Energy Laboratory (NREL) in Colorado, while in Chapters 8 and 9, the topics of light capture and photon management are covered. This makes a truly exciting combination of material for anyone who is studying or has interest in the application of thin film PV.

Each chapter provides a coherent and authoritative account of the topics covered. Together they provide a stimulating view of new possibilities in thin film PV to meet the challenges of increasing the adoption of PV solar energy and reducing our carbon emissions from the use of fossil fuels. These challenges include the need for both high beginning-of-life efficiency and stable long-term performance. This directly impacts the levelised cost of electricity and the carbon impact. In the long term, with the expected growth in thin film PV production, we must look to improving sustainability through the choice of abundant materials and minimising the use of materials through greater efficiency of utilisation both within the device and in manufacturing.

The idea for this book came from the excellent research collaboration in the UK on thin film PV under the Research Councils UK Energy Programme, PV SUPERGEN. This project ran for a total of eight years from 2004 to 2012 and brought together many inspiring ideas that could potentially transform thin film PV production. As with all research projects there is always so much more that could be done and new materials to explore, but the legacy of this research are the research teams that have built on these early successes. Many of the chapters of this book are authored by members of the PV SUPERGEN collaboration and I extend my gratitude to all of the 50 plus researchers who have contributed to this research. The thin film PV research community is the richer and stronger from this formative collaboration and I hope this book will be an inspiration to all those who are interested in the topic.

Stuart J. C. Irvine

Editor

Centre for Solar Energy Research, OpTIC Centre, Glyndwr University, St Asaph, North Wales, UK