Current-voltage characteristics:

The current-voltage (I–V) characteristics of a solar cell describe how the output current varies with the voltage across the cell under illumination. This curve is fundamental for evaluating the performance of photovoltaic devices.

1. Short-Circuit Current (I_SC):

The maximum current when the voltage is zero (terminals shorted). It reflects the light-generated current and is proportional to the light intensity and the active area of the cell.

2. Open-Circuit Voltage (V_OC):

The maximum voltage when the current is zero (no load connected). It represents the maximum possible voltage the cell can produce and is a measure of the recombination losses within the device.

3. Maximum Power Point (P_max):

The point on the curve where the product of current and voltage (I × V) is highest. This defines the optimal operating condition at which the solar cell delivers its maximum power output.

4. Fill Factor (FF):

A measure of the "squareness" of the I–V curve, calculated as: $$FF=\frac{I_m\times V_m}{I_{SC}\times V_{OC}}$$ where $$I_m$$ and $$V_m$$ are the current and voltage at maximum power. A higher fill factor indicates a more efficient solar cell, as it means the cell can deliver more power closer to its theoretical maximum.