why is concentrate solar cell with increasing the solar intensity, electric filed decrees? or in very little intensity of light the behavior of electric filed or EQE chanage?
due to increase pv cell temperature, the voltage decreased by 2.3m volt/c . this lead to reduce the forbidden gab energy and absorb photons with less energy, this causes less voltage and power and increase amount of current .
I'm working in on concentrated pv array experimentally and the increase the temperature caused reduced in voltage about 1-2 volt at 9Am-12 Pm for 330 watt traditional p-si pv
What do you mean with electric field. The electric field is an internal parameter, normally appearing in the space charge region of the solar cell. If you mean the open circuit voltage, then the answer of the colleagues above is okay. Generally speaking the open circuit voltage is expressed by
Voc= nVt ln(Iph/ Io)
where n is the ideality factor, Vt the thermal voltage , iph is the photocurrent and I0 is the reverse saturation current,
The open circuit voltage increases with Iph which is proportional to incident solar radiation with a logarithmic relation. It decreases with temperature T because of the appreciable dependence of I0 on the temperature. So, By operating the solar cell under concentrated solar radiation the open circuit voltage may generally decrease where the temperature decrease may overcome the increase due to Iph.
The part of the question concerning the EQE needs more clarification.
just a complementary information of Zekry's answer about th electric field.
At PN junction when electron (in N region ) diffuse (difusion phenomena is from higher concentrating environment to lower concentrating ) toward P region, positive charge is created in N region. the same for hole diffusion (from P region to N region), negative charge is created in P region. this distribution of charge (positive and negative) an electrical field is created in order to maintain the diffusion equilibrium. the zone which limited the negative and positive charge is named the space charge region . this region is characterized by an electric field and poor concentration of mobile charge (electrons and holes)