The answer to your first question is:

• Irradiance-to-PV current conversion factor - this depends on temperature (NOCT) and ambient wind
• Diode current
• Series resistance
• Shunt resistance.

The second question is not very clear to me.

-Sanjay

Most the factors that can adversely impact the solar cell efficiency are environmentally related including availability of solar radiation, dust accumulation, rain, etc. In addition, degradation in the reliability of the power electronic components that are integrated with the solar cells can also adversely impact the efficiency.

Hope this helps answer your question!

Professor Yehia Khalil

Yale University

USA

At the device level, I would seriously look at the external quantum efficiency. This is highly dependent on the photon penetration depth and how many election-hole pairs are lost in the g-r and defect sites.

Thank's so much  Sanjay,Professor Yehia anf Shahid Aslam fo your helpful answers

Fatima

voltage temperature ,illumination intensity

The following factors may affect the solar cell efficiency:

 Availability of solar radiation

Wind velocity

Ambient temperature

Shadow factor

Dust accumulation

Type of the PV cell

Age of the cells

Electronic / electrical system efficiency

Dr Muzathik

South Eastern University of Sri Lanka

"what's the main factor which can affect on solar cell efficiency and their parameters?" --> 1.) For a single-junction cell, the band-gap energy of the absorber material determines the maximum attainable conversion efficiency (cf. http://www.pveducation.org/pvcdrom/solar-cell-operation/detailed-balance and http://www.lehrbuch-photovoltaik.de/abbildungen/hp_bild_4.25_theoretischer-wirkungsgrad-solarzelle-bandabstand.png). 2.) For a given material, light trapping and the dark current density J_0 (i.e., recombination; the smaller J_0, the better the cell) most severely limit the actual conversion efficiency (cf. http://www.pveducation.org/pvcdrom/design/solar-cell-design-principles).

"In a solar cell why we can't see the photovoltaïque effect ,what's the problem in our cell?" --> Which type of solar cell are you talking about? Can you show any measurement results explaining your "we can't see"?

The Temperature of PV cells, Shading effect, Charge Controller and Solar Cell’s Characteristics are some other factors that should be considered.

Thank so much dear professor for your answers

prof Jan-Martin I work on solar cell based thin film,

is there any solution to improve our device parameters?

The following factors also may be affect on solar cell efficiency

Incident angle ( Orientation ) location shade, Maintenance, Lifetime. 

What material(s) are your thin-film based solar cells made of? What kind of contacts do you employ?

Dear professor Jan-Martin I work on CZTS thin film based solar cells and I use gold and FTO as contacts.

Thank's so much Prof G.G.Yao for your helpful answers

God blessed you

best regards

Fatima

Dear Fatima,

You see photovoltaic effect when your specimens show good diode behavior in dark, pointing out the existing field region that will separate the electron hole pairs

In addition you have to see good photoelectric effect which is the indicated by appreciable photcurrent when the cell is short circuit.

The complementing factors are low series resistance and high shunt resistance to avoid the losses of the phtovoltaic effect.

So, you have to observe:

- High short circuit current

- High open circuit volatge

- High fill factor.

For more information please follow the link:https://www.researchgate.net/publication/236002879_A_course_on_photo-voltaic_array_systems

best wishes

Book A course on photo-voltaic array systems