Development of photovoltaic technologies for global impact

Photovoltaic solar energy (PV) is expected to play a key role in the future global sustainable energy system. It has demonstrated impressive developments in terms of the scale of deployment, cost reduction and performance enhancement, most visibly over the past decade. PV conversion is and can be done with a wide range of materials, device architectures and technologies, at very different levels of technical and economic maturity. In this context it is customary to distinguish between first, second, third, and sometimes even fourth generation PV. This has initially been very useful to clarify the complex and, for many, confusing landscape of PV. In this paper it is argued, however, that in view of actual developments in PV over the past few decades there are good reasons to adopt another approach, that does more justice to the role and potential of existing and new PV concepts and technologies.