Hi Hubert AZODA KOFFI

It is important to note that 'Is' depends on the temperature as well.

Is = q*A*(D*ni^2)/(L*ND)

Several parameters here depend on the temperature, but 'ni' has the most important effect. When the temperature increases the band gap reduces, and it will result in an increase in 'ni'.

Please take a look at the following link:

https://sinovoltaics.com/learning-center/basics/effect-of-temperature/

Dear

Hubert

At the first, and as you know that : like all other semiconductor devices, solar cells are sensitive to temperature. Increases in temperature reduce the bandgap of a semiconductor, thereby effecting most of the semiconductor material parameters. The decrease in the band gap of a semi- conductor with increasing temperature can be viewed as increasing the energy of the electrons in the material. Lower energy is therefore needed to break the bond. In the bond model of a semiconductor bandgap, a reduction in the bond energy also reduces the bandgap. Therefore increasing the temperature reduces the bandgap.

In a solar cell, the parameter most affected by an increase in temperature is the open-circuit voltage. The impact of increasing temperature is shown in the figure below.

........Fig 1.....

The open-circuit voltage decreases with temperature because of the temperature dependence of I0. The equation for I0 from one side of a p-n junction is given by;

.......Fig 2....

where:

q: is the electronic charge given in the constants page.

A: is the area.

D: is the diffusivity of the minority carrier given for silicon as a function of doping in the Silicon Material Parameters page;

L: is the minority carrier diffusion length;

ND: is the doping; and

ni: is the intrinsic carrier concentration given for silicon in the Silicon Material Parameters page.

In the above equation, many of the parameters have some temperature dependence, but the most significant effect is due to the intrinsic carrier concentration, ni. The intrinsic carrier concentration depends on the bandgap energy (with lower bandgaps giving a higher intrinsic carrier concentration), and on the energy which the carriers have (with higher temperatures giving higher intrinsic carrier concentrations).

+++++++++----------------++++++++++

For more information you could benefit from this valuable article at:

https://www.pveducation.org/pvcdrom/solar-cell-operation/effect-of-temperature

I hope it will be helpful...

With my best regards...

Also I want to add the following:

The open-circuit voltage, VOC, is the maximum voltage available from a solar cell, and this occurs at zero current. The open-circuit voltage corresponds to the amount of forward bias on the solar cell due to the bias of the solar cell junction with the light-generated current. The open-circuit voltage is shown on the IV curve below.

------Fig 3------

An equation for Voc is found by setting the net current equal to zero in the solar cell equation to give:

A casual inspection of the above equation might indicate that VOC goes up linearly with temperature. However, this is not the case as I0 increases rapidly with temperature primarily due to changes in the intrinsic carrier concentration ni. The effect of temperature is complicated and varies with cell technology. See the page “Effect of Temperature” for more details

VOC decreases with temperature. If temperature changes, I0 also changes.

-----------++++++++++++---------++++++++

For more information you could benefit from this valuable article about "Open-Circuit Voltage" at:

https://www.pveducation.org/pvcdrom/solar-cell-operation/open-circuit-voltage.

Dear Hubert AZODA KOFFI ,

This subject has been intensively investigated in the literature. The Voc decreases with temperature as the colleagues explained in their answers. This decrease is because of the appreciable increase of the reverse saturation current Is.

For detailed information about the effect of temperature on the solar cell characteristics see the book chapter in the link: https://www.researchgate.net/publication/323309527_Solar_cells_and_arrays_Principles_analysis_and_design

Best wishes