Light induced degradation is a loss of module power that happens when cells are first exposed to light. In crystalline silicon modules it is mostly caused by boron-oxygen defects. In crystalline modules it usually costs a few percent in the first days of sun, while amorphous silicon modules can lose much more over their first months. You will not see it on the module. It shows as lower output power, short-circuit current, open-circuit voltage and fill factor. Confirm it with IV tracing or flash testing, and compare stabilized results and early production against nameplate. EL and IR imaging can help. Severe cases can cause mismatch and hot spots that show up in an IR camera. If early losses look larger than expected, have an accredited lab confirm them and claim the missing power under the warranty. To prevent it, choose low-LID or gallium-doped cell technology, check the cell type in the bill of materials, and include initial stabilization losses in yield estimates.
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caused_byc1 verified · fact Sunlight exposure
Power drops during the initial stabilization period when the module is first exposed to light.
sec=h3 h=950db263c013sec=2.2.1 h=c22ec9adead4sec=h4 h=c8bc75bb2d8dverified by: joshuahamsaverified on: 2026-10-16
c2 verified · fact Boron-oxygen defects
Boron-oxygen complexes form in boron-doped cells, mostly Czochralski mono-Si with leftover oxygen. They trap charge carriers.
sec=h46 h=1ff4ba1a643esec=h5 h=048d7dac489dsec=2.2.1 h=c22ec9adead4sec=h69 h=bdc3ce4bcd6cverified by: joshuahamsaverified on: 2026-10-16
affectsc3 verified · fact Solar cell
Mostly affects p-type boron-doped mono and multi crystalline cells. n-type and Ga-doped cells are much less affected.
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cverified by: joshuahamsaverified on: 2026-10-16
presents_asc4 drafted · lead Reduced STC output power
Seen early in system life. It does not come with any visual defect.
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc5 drafted · lead Reduced short-circuit current
sec=h6 h=0189f40b9ccfsec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc6 verified · fact Low module open-circuit voltage
sec=h6 h=0189f40b9ccfsec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cverified by: joshuahamsaverified on: 2026-10-16
c7 verified · fact Reduced fill factor
sec=h6 h=0189f40b9ccfverified by: joshuahamsaverified on: 2026-10-16
c8 drafted · lead Non-uniform EL pattern
A patchwork pattern in EL images that grows more uneven can sometimes show that degradation is under way.
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc9 drafted · lead Hotspot in IR image
Only for serious LID above 10%, seen mainly in early PERC cells made before LID was mitigated in manufacturing.
sec=h69 h=bdc3ce4bcd6cleads_toc10 drafted · lead Module Hotspot from Cell Damage
LID can cause mismatch between cells, which can trigger hot spots and speed up ageing.
sec=h6 h=0189f40b9ccfsec=h69 h=bdc3ce4bcd6cdetected_byc11 drafted · lead IV curve tracing
sec=h6 h=0189f40b9ccfsec=front h=ea45629cb646sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc12 drafted · lead Electroluminescence imaging
sec=h6 h=0189f40b9ccfsec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc13 drafted · lead Infrared thermography
sec=h6 h=0189f40b9ccfsec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc14 drafted · lead Flash testing
Compare stabilized flash-test results with nameplate and with the degradation expected for the technology.
sec=front h=ea45629cb646sec=h2 h=0877e796b00fc15 drafted · lead Performance monitoring
Compare early-life production trends with nameplate and technology-specific expectations.
sec=front h=ea45629cb646sec=h2 h=0877e796b00fc16 drafted · lead Accredited laboratory testing
Use an accredited PV test laboratory to confirm the underperformance.
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cmitigated_byc17 drafted · lead Low-LID module selection
sec=front h=ea45629cb646sec=h2 h=0877e796b00fc18 drafted · lead Initial degradation in yield model
Underestimating initial degradation directly affects energy yield predictions.
sec=front h=ea45629cb646sec=h2 h=0877e796b00fsec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc19 drafted · lead Gallium-doped cells
Using Ga instead of B as the dopant removes B-O complex formation. Residual B impurities can still cause some LID.
sec=2.2.1 h=c22ec9adead4sec=h46 h=1ff4ba1a643ec20 verified · fact In-line cell stabilization
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cverified by: joshuahamsaverified on: 2026-10-16review note: support check: partial - Passages say manufacturers adapted production to stabilise cells in-line, but this is described mainly for LeTID rather than clearly for LID.
c21 drafted · lead Bill of materials verification
Check the cell type.
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc22 drafted · lead Power warranty verification
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc23 drafted · lead Warranty claim
Claim the missing power once underperformance is confirmed.
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cc24 drafted · lead Contractual loss tolerance
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6ctypical_power_lossc25 verified · fact 1–3 PERCENT
Conditions: Classic LID in crystalline silicon modules, occurring only in the first days of sun exposure
sec=h46 h=1ff4ba1a643esec=h69 h=bdc3ce4bcd6cverified by: joshuahamsaverified on: 2026-10-19review note: reviewer 2026-10-17: the compiler-flagged conflict is a different technology (amorphous vs crystalline silicon), not disagreement
c26 drafted · lead ≤ 30 PERCENT
Conditions: Light soaking effect across all module technologies (upper bound)
sec=h3 h=950db263c013review note: support check: partial - The 30% upper bound is stated, but the claim that it applies across all module technologies is not.
c27 verified · fact 10–30 PERCENT
Conditions: Amorphous silicon modules (Staebler-Wronski effect) within the first months outdoors
sec=h4 h=c8bc75bb2d8dverified by: joshuahamsaverified on: 2026-10-16review note: reviewer: the compiler-flagged conflict is a different scenario or technology, not disagreement
c28 drafted · lead ≤ 10 PERCENT
Conditions: LeTID variant at elevated temperature, which can add to the LID loss
sec=h46 h=1ff4ba1a643esec=h5 h=048d7dac489dsec=h69 h=bdc3ce4bcd6crelated_to c11related_to c3related_to c10