A solar module

As long as this blog lacks a sense of direction, I expect that I'll be jumping from topic to topic at random with no organization. So today I thought I would show a small solar module that I made at the Ångström Laboratory, which is where I work. The module is a copper-indium-gallium-diselenide cadmium-free device, but I'm not going to explain that at this time. This particular module is about three years old, and unfortuneately, this picture wasn't taken until the device had already started to oxidize. That's why it looks like a map of the earth's land masses was printed on it. I had glued the protective glass on it - encapsulated, in the solar world - rather sloppily. It originally had a satiny black appearance, which is the look any self-respecting solar module should strive for since it's the color that absorbs the most sunlight.
The outer dimensions of the glass are 12.5 by 12.5 cm, but only the black area between the electrical contacts actively contributes to electricity generation. And this is where it starts to get technical. The graph I've included namely shows the module's electrical operating characteristics when under sunlight, although, to be precise, I faked the sunlight by using a light bulb whose intensity and color spectrum more or less imitate that of your basic 'standard' sun. The word 'standard' should, of course, make your eyes roll - maybe I'll say something about it some other day. Anyway, back to the graph: the vertical axis is current, the horizontal one is voltage. There are three little x's on the curve. One marks the point where the device is short-circuited such that the voltage is zero and the current is maximized, noted as Isc in the table. Another is when the circuit is open such that the current is zero and the voltage is maximized, noted as Voc in the table. The third is the one of most interest. It lies in the middle of the curve at the maximum power point where the product of I times V - power, that is - is maximized. Any external circuit that tries to be powered by a solar module should try to draw just the right amount of current at the maximum power point if it wants the most power that can be produced.
The table, besides showing the active area of the module, Isc and Voc, also calculates two other things: fill factor FF, and efficiency. The fill factor is a measure of how 'square' the curve is and is used to calculate the efficiency of a device, although fill factor has a different meaning to my beer drinking friends who are contemplating their beer glasses at our regular Friday night beer gatherings (this could be a topic for another day). The efficiency measures, in percent, how much of the sun's power can be delivered by the device in the form of electricity and is calculated by multiplying Isc times Voc times FF. This particular module is 14.8% efficient. In terms of power output, it can produce 14.8% of the sun's power, which, for a 'standard' sun just happens to be 1000W per square meter. In other words, if this module were as big as 1 square meter it could produce 148W of power (if the sun were 'standard', ha ha). But this particular little module is only 76.8 square centimeters (=0.00768 square meters) so it can produce 0.00768 times 148 equals to 1.14W, a result that makes me glow with pride.
Oh, by the way, I should mention that the I-V curve above was measured at NREL, the National Renewable Energy Lab in Colorado, a former employer of mine where they do such internationally recognized efficiency measurements of solar devices to keep people like me honest.