1.2.5 Aspects Of Solar Cell Efficiency
2.5 Aspects of Solar Cell Efficiency
Most of the energy that reaches a cell in the form of sunlight is lost before it is converted to electricity. The usual efficiency of these systems ranges between 10% to 15%, though sometimes this efficiency increases to 30% and more. Certain physical properties affect the cell efficiency which we will briefly state.
1- Reflection:
Studies show that untreated silicon reflects 36% or more of sunlight that strikes it. Chemically coating and texturing the surface reduces the reflection to around 5%.
2- Light with too little or too much energy:
The sunlight has a wide variety of energies, one of which will be suitable to the energy band gap of the material composing the PV module (for example 1.1eV for silicon). …show more content…
At too low temperatures, the thermal energy is less able to free charge carriers from silicon or the dopant element. On the contrary, too high temperatures cause lattice vibrations that interfere with the passage of charge carriers. At extremely high temperatures the junction of the doped semiconductor will lose its power to separate the charges, thus the charge carriers having so much energy start crossing the junction in both directions (n-type side to p-type side and vice versa) as if the barrier field were not there. This affects the activity of the cell and reduces its efficiency.
Most current work on cells is oriented to treat all these factors in order to increase the cell efficiency but while lowering the cost. 2.6 Modelling of PV Cell
Figure 2-d shows the equivalent circuit of PV cell. Equivalent circuit has a current source (photocurrent), a diode parallel to it, a resistor in series describing an internal resistance to the flow of current and a shunt resistance which expresses a leakage current.
Figure 2-e: Equivalent circuit of a single diode model of a solar
Most of the energy that reaches a cell in the form of sunlight is lost before it is converted to electricity. The usual efficiency of these systems ranges between 10% to 15%, though sometimes this efficiency increases to 30% and more. Certain physical properties affect the cell efficiency which we will briefly state.
1- Reflection:
Studies show that untreated silicon reflects 36% or more of sunlight that strikes it. Chemically coating and texturing the surface reduces the reflection to around 5%.
2- Light with too little or too much energy:
The sunlight has a wide variety of energies, one of which will be suitable to the energy band gap of the material composing the PV module (for example 1.1eV for silicon). …show more content…
At too low temperatures, the thermal energy is less able to free charge carriers from silicon or the dopant element. On the contrary, too high temperatures cause lattice vibrations that interfere with the passage of charge carriers. At extremely high temperatures the junction of the doped semiconductor will lose its power to separate the charges, thus the charge carriers having so much energy start crossing the junction in both directions (n-type side to p-type side and vice versa) as if the barrier field were not there. This affects the activity of the cell and reduces its efficiency.
Most current work on cells is oriented to treat all these factors in order to increase the cell efficiency but while lowering the cost. 2.6 Modelling of PV Cell
Figure 2-d shows the equivalent circuit of PV cell. Equivalent circuit has a current source (photocurrent), a diode parallel to it, a resistor in series describing an internal resistance to the flow of current and a shunt resistance which expresses a leakage current.
Figure 2-e: Equivalent circuit of a single diode model of a solar