Altermatt Lecture:   The Solar Spectrum


1.1:  Introduction

The performance of solar cells may depend sensitively on the solar spectrum: some cells are more efficient in reddish illumination, other in bluish illumination. To understand solar cells, it is good to have some basic knowledge of the solar spectrum and its variability. This is developed in this lesson.

In this lesson, you will learn

  • about the shape of the extraterrestrial solar spectrum
  • why it is advantageous to quantify the spectrum in terms of photon flux rather than light intensity
  • why a defined reference spectrum is necessary to test solar cells
  • which mechanisms cause the terrestrial spectrum to be different from the extraterrestrial one
  • what scattering of light is and how it influences the terrestrial spectrum
  • finally, if you like, you can calculate the spectrum yourself with the easy to use software SMARTS [1].

Your learning is considerably more efficient if you do more than reading the following pages. For most people, it is most efficient to:

  • shortly summarize the main thought (optimally containing a keyword), to

Photon flux of AM0 vs AM1-5g

Figure: Photon flux of the extraterrestrial (AM0) and terrestrial (AM1.5g) spectra. Figure from [1].

  • attach a picture to it (which optimally reflects the dynamics of the subject), and to
  • go through your summary the next day, in a week's time, and in a month's time.

To do this, you may download an MSword document, containing the subject titles and the pictures. Saving time by "only reading it" usually does not pay off the extra amount of time needed later for recovering forgotten knowledge.

Some pages contains advanced material. These are marked with an asterisk.


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