Short circuit current and Open circuit voltage -- Illumination

[says]

Homework Statement

I'm trying to understand the dependence of short circuit current and open circuit voltage on illumination.

Short-circuit current is due to the generation and collection of light-generated carriers -- so does that mean the short circuit current is linearly dependent on illumination? i.e. The more illuminated a solar cell, the higher it's short circuit current will be? and vice versa.

Open-circuit voltage is the maximum voltage available from a solar cell, and occurs at at zero current -- so does that mean open-circuit current is negatively dependent on illumination? i.e. The less illuminated a solar cell, the higher it's open circuit voltage.

Homework Equations

The Attempt at a Solution

 

[CWatters]

Have a look here...
http://www.wholesalesolar.com/solar-information/solar-panel-efficiency
In particular the dotted lines on this graph..

It shows how the short circuit current increases with illumination. The open circuit voltage doesn't change much.

 

[CWatters]

Open-circuit voltage is the maximum voltage available from a solar cell, and occurs at at zero current -- so does that mean open-circuit current voltage is negatively dependent on illumination? i.e. The less illuminated a solar cell, the higher it's open circuit voltage.

No. As mentioned above the open circuit voltage doesn't change much with illumination but it does increase slightly.

However there is a side effect... In bright sun a panel is more likely to heat up and open circuit voltage is inversely proportional to temperature (open circuit voltage falls when they get hot). See the solid lines on the graph.

 

[says]

Can we say that 'bright sun' is more illuminated than a 'not bright sun' though? Therefore meaning that open circuit voltage is inversely proportional to illumination? Sort of by association...

Bright sunlight = increased illumination = higher temperature of the panel = reduces open circuit voltage ?

 

[CWatters]

I don't know which effect is stronger...

Increased illumination = higher voltage
or
Increased illumination = hotter = lower voltage