Characterization Techniques in Solar Photovoltaics

A: This setup directly produces a calibrated IV curve with low contact error, which is what series resistance extraction needs. The outdoor rack gives realistic irradiance but uncontrolled spectrum and temperature smear the slope near Voc. Electroluminescence flags shunts and cracks but doesn't give IV slope. UV–Vis isolates optics and never biases the junction.

A: PID testing recreates field-driven Na⁺ drift from soda-lime glass into the cell, lowering shunt resistance. EVA photo-bleaching slightly changes transmission but not abrupt power loss. Silver migration needs sustained DC current inside the cell, not external bias. Thermal fatigue shows up after many temperature cycles, not damp-heat bias stress.

A: Spectral mismatch correction rescales current downward when the simulator over-represents wavelengths favorable to the DUT. Multiplying would inflate current further. Efficiency-only correction breaks the IV curve consistency. Voc weakly depends on spectrum but Isc is the primary term affected.

A: EL quickly reveals crack-induced dark regions and fits inline screening. Lock-in thermography is slower and more sensitive to subsurface defects than needed. Suns-Voc looks at recombination behavior, not physical cracks. SIMS destroys the sample and targets chemistry, not mechanical damage.