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qianjuan@laserdl.cn
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Building A1, Phase 1.1, Intelligent Manufacturing Industrial Park, Dachang Hui Autonomous County, Langfang City, Hebei Province
Deresheke (Langfang) Technology Co., Ltd
Chasing Light Classroom | The 'invisible stumbling block' of solar cells: how to solve the problem of metastability?
Date: 2025-10-11Read: 1
The efficiency of solar cells is a core concern in the industry, but crystalline silicon TOPCon、 Mainstream components such as perovskite cannot avoid an 'invisible trouble'——Metastable state phenomenon.The initial efficiency of illumination drops sharply, the IV test curve fluctuates between high and low, and the laboratory data and outdoor power generation performance frequently deviate, leaving many pitfalls for production testing and power generation evaluation.Today, we will dismantle this targeted solution and teach you how to deal with metastable interference, making battery performance calculations more accurate.
The core characteristics of metastable phenomena
TOPCon component special mechanism:
Voltage index dependence: C_d ∝ exp (qV/kT)
Linear dependence of current: C_d ∝ I
Significantly near the maximum power point (Pmax), the value is much larger than the junction capacitance.
Key considerations for IV testing
Normalization of excited states:
The larger the reverse bias, the wider the depletion layer, and the smaller the capacitance value (C_j ∝ (V_bi - V) ^ {-1/2}).
Affects high-frequency response and limits the charging and discharging speed during light intensity transients.
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Phenomenon:Transient IV curve caused by charging and discharging of metastable components
Solution：
Add before testing5-minute dark state rest(Release interface stored charge)
adoptComparison of Multi rate ScanningDiagnostic capacitance effect (0.1 V/s vs. 1 V/s)
introduceC-V testingQuantitative interface charge density (auxiliary correction IV result)
Association between outdoor power generation and laboratory data
Special optimization suggestions for TOPCon components
Pulse light source preprocessing(1 solar intensity x 3 minutes, with intervals of 1 minute x 3 times)
Embedded adaptive algorithm:Real time monitoring of IV curve drift, dynamically extending/shortening preprocessing time
Output correction report:Automatically annotate the "metastable compensation factor" (based on capacitance test data)
choiceLow metastable sensitivity batchAs a calibration benchmark
Use DLTS every month（Deep level transient spectrum）Verify the stability of the defect state of the reference component
Summary: Core Risk Control Path
Execution priority：
Develop enterprise level 'IV Test Preprocessing Specification'
Develop capacitance efficiency correlation correction algorithm
Establish TOPCon metastable sample library (covering LID)/LETIDcase
Attachment: Example of Test Record Representation
Through the above framework, it is possible to systematically avoid the interference of metastable states on IV testing, ensuring consistency between laboratory data and outdoor power generation performance.