• Exposes the significant effect of defects in semiconductors and interfaces that affect the performance of these devices


• Presents experimental results in a simple way so that the materials become useful even for undergraduate students


• Discusses insights gained from experimental results observed in CdTe and CIGS thin-film solar cells, with a view to deepen researchers’ fundamental understanding of device physics and guide future improvements in device efficiency

Rapid introduction of renewable energy is essential in order to meet future energy demands without further polluting the environment. Solar energy conversion plays a very important role in this, 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 diselenide (CIGS) and dye sensitised 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 in 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 multilayer solar cells. This design has been experimentally tested using the well researched GaAs/AlGaAs system and initial devices have shown impressive device parameters (Voc~1175 mV, FF~0.85 and Jsc~12 mA cm-2). In particular, the Voc represents the highest recorded value together with highest possible FF values to date for a single PV device, indicating the right approach for PV solar cell development. This device is capable of absorbing all radiation (UV, visible & infra-red) within the solar spectrum, and combines “impact ionisation” and “impurity photovoltaic” effects. The improved device understanding presented in this book should impact and guide future device design and low-cost thin film solar panel manufacture.

Students and researchers in Chemistry, Material Science, Physics, Mathematics and Electronic Devices