☀️ Solar Cell I-V Curve

A photovoltaic cell is a large-area p-n junction that converts photons into electricity. The Shockley diode equation gives the current as a function of terminal voltage; the operating point shifts with irradiance and temperature.

Irradiance G 1000 W/m²

Temperature T 300 K

Ideality factor n 1.0

Dark current I₀ 1e-10 A

Series resistance R_s 0.5 Ω

V_oc: - V

I_sc: - A

P_max: - W

FF: -

PCE: - %

V_mp: - V

How it works

The single-diode model with series resistance gives the implicit I-V equation:

I = I_ph − I₀ ⋅ [exp(q(V + IR_s) / nkT) − 1]

The photocurrent I_ph = I_ph0 ⋅ G/G_STC scales with irradiance. Increasing temperature reduces V_oc (≈ −2 mV/K for silicon) while slightly increasing I_sc.

Fill factor FF = P_max / (I_sc ⋅ V_oc) measures the "squareness" of the I-V curve. High series resistance degrades FF. Ideal cells have FF ≈ 0.85.

The power conversion efficiency PCE = P_max / (G ⋅ A_cell) where A_cell = 0.01 m² (100 cm²).

The left half of the canvas shows a simplified band diagram with the p-n junction, depletion region, photon absorption, and minority carrier drift under the built-in field.