1 Introduction
5
Figure 1.3 gives a brief overview of the various solar cell technologies, including
those in a pre-commercial phase. It also indicates the typical efficiency of commercially available PV modules, and their long-term efficiency potential. It should be
noted that individual record solar cell efficiencies are typically 15–30% higher than
the efficiencies of commercial modules
2 .
The focus of this book will be on those solar technologies, which are most widely
applied, in particular on crystalline silicon (c-Si), because of its high share (95%)
of the PV market: This branch of PV technology will be discussed in Chaps. 5 and
7. Chapter 8 will treat existing thin-film technologies, which make up most of the
remaining 5% of the PV module market.
Chapters 2, 3 and 4, next up, will discuss basic concepts used for all PV
Technologies:
• Chapter 2 will describe the solar spectrum under various atmospheric conditions
• Chapter 3 deals with the Basic Theory of Solar Cells
• Chapter 4 describes losses within solar cells—optical losses and electrical
(recombination) losses.
Chapter 6 will discuss amorphous silicon layers and solar cells; the latter are
today mostly used for indoor applications or for the internet of things (IOT). The full
fabrication of modules will be treated in Chap. 9, whereas the system aspects of PV
will be presented in Chaps. 10–12. Finally, Chap. 13 will focus on the role of PV
in the global energy system.
Considering the continuous PV market growth, and a future annual volume production in the range of TW p , research is still ongoing, both for improving existing
commercialized technologies, and for figuring out processes allowing for higher efficiency. In parallel, one is preparing for future technologies, in particular those which
will be able to surpass the efficiency of crystalline silicon, as will be discussed later.
1.3 Photovoltaics: Technology Evolution
By switching from selenium-based solar cells, which had an efficiency of 0.5% in
1952, to silicon, Chapin et al. were able to demonstrate 6% efficient solar cells in
1954 [3]. These results triggered research and commercialisation, initially mostly
for space applications. For several decades, the terrestrial PV market was limited to
off-grid applications. The low manufacturing volumes translated into high prices per
Watt-peak ($7–8 per W p in 1990), for both c-Si and thin film (a-Si): this prevented
massive deployment of PV for power generation.
2 They are several reasons for the efficiency difference between record solar cells and commercial
modules; those include: the space between the solar cells, the non-active area close to the module edges, the electrical losses in interconnection ribbons, the simplified processes used in mass
production, the reduced homogeneity for large devices, etc.
5
Figure 1.3 gives a brief overview of the various solar cell technologies, including
those in a pre-commercial phase. It also indicates the typical efficiency of commercially available PV modules, and their long-term efficiency potential. It should be
noted that individual record solar cell efficiencies are typically 15–30% higher than
the efficiencies of commercial modules
2 .
The focus of this book will be on those solar technologies, which are most widely
applied, in particular on crystalline silicon (c-Si), because of its high share (95%)
of the PV market: This branch of PV technology will be discussed in Chaps. 5 and
7. Chapter 8 will treat existing thin-film technologies, which make up most of the
remaining 5% of the PV module market.
Chapters 2, 3 and 4, next up, will discuss basic concepts used for all PV
Technologies:
• Chapter 2 will describe the solar spectrum under various atmospheric conditions
• Chapter 3 deals with the Basic Theory of Solar Cells
• Chapter 4 describes losses within solar cells—optical losses and electrical
(recombination) losses.
Chapter 6 will discuss amorphous silicon layers and solar cells; the latter are
today mostly used for indoor applications or for the internet of things (IOT). The full
fabrication of modules will be treated in Chap. 9, whereas the system aspects of PV
will be presented in Chaps. 10–12. Finally, Chap. 13 will focus on the role of PV
in the global energy system.
Considering the continuous PV market growth, and a future annual volume production in the range of TW p , research is still ongoing, both for improving existing
commercialized technologies, and for figuring out processes allowing for higher efficiency. In parallel, one is preparing for future technologies, in particular those which
will be able to surpass the efficiency of crystalline silicon, as will be discussed later.
1.3 Photovoltaics: Technology Evolution
By switching from selenium-based solar cells, which had an efficiency of 0.5% in
1952, to silicon, Chapin et al. were able to demonstrate 6% efficient solar cells in
1954 [3]. These results triggered research and commercialisation, initially mostly
for space applications. For several decades, the terrestrial PV market was limited to
off-grid applications. The low manufacturing volumes translated into high prices per
Watt-peak ($7–8 per W p in 1990), for both c-Si and thin film (a-Si): this prevented
massive deployment of PV for power generation.
2 They are several reasons for the efficiency difference between record solar cells and commercial
modules; those include: the space between the solar cells, the non-active area close to the module edges, the electrical losses in interconnection ribbons, the simplified processes used in mass
production, the reduced homogeneity for large devices, etc.