Rapid progression and subsequent saturation of polarization-type potential-induced degradation of n-type front-emitter crystalline-silicon photovoltaic modules
Rapid progression and subsequent saturation of polarization-type potential-induced degradation of n-type front-emitter crystalline-silicon photovoltaic modules
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DOI：
10.7567/jjap.57.122301
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发表时间：
2018-12-01
影响因子：
1.5
通讯作者：
Ohdaira, Keisuke
中科院分区：
文献类型：
--
作者：
Yamaguchi, Seira;Nakamura, Kyotaro;Ohdaira, Keisuke
在这项研究中，我们研究了由前p(+)发射极的n型单晶硅电池制成的光伏组件中的电位诱导退化(PID)的进展。在对模块施加-1000V偏置的PID测试中，它们在5 S内开始退化，并且在60秒内达到饱和。这一行为表明，前向钝化膜中的正电荷积累是引起膜内正电荷积累的主要原因。在-1500V的偏压下进行的PID测试表明，降解速率强烈地依赖于施加的偏置，而饱和值与施加的偏置无关。通过施加+1000V的正偏置，对先前经历了持续5分钟和10分钟的PID测试的退化模块进行再生测试。无论降级测试持续时间如何，所有降级模块都在60秒内完全恢复其性能损失。在这些结果的基础上，我们提出这些正电荷来源于从中性和带负电荷的K中心提取电子而形成的带正电荷的K中心。这个模型很容易解释观察到的降解和再生行为。为了验证我们的模型，我们测量了氮化硅钝化膜在PID前后的固定正电荷密度(Q(F))，发现Q(F)呈现出相似的饱和行为。此外，饱和Q(F)值与K中心密度处于同一数量级。这些结果支持我们包含K个中心的充电过程的模型。(C)2018年日本应用物理学会
In this study, we investigated progression of potential-induced degradation (PID) in photovoltaic modules fabricated from n-type-based crystalline-silicon cells with front p(+) emitters. In PID tests in which a bias of -1000 V was applied to the modules, they started to degrade within 5 s and their degradation saturated within 60s. This behavior suggested that the PID was caused by positive charge accumulation in the front passivation films. Performing PID tests with a bias of -1500 V revealed that the degradation rate strongly depended on the applied bias whereas the saturation value was independent of the applied bias. Regeneration tests on degraded modules previously subjected to PID tests for durations of 5 and 10 min were performed by applying a positive bias of +1000V. All the degraded modules completely recovered their performance losses within 60s regardless of the degradation test duration. On the basis of these results, we proposed that these positive charges originate from positively charged K centers formed by extracting electrons from neutral and negatively charged K centers. This model readily explains the observed degradation and regeneration behavior. To test our model, we determined the fixed positive charge densities (Q(f)) of a silicon nitride passivation film before and after PID, for which it was found that Q(f) showed similar saturation behavior. Additionally, the saturated Q(f) value was of the same order as K center density. These results support our model involving a charging process of K centers. (C) 2018 The Japan Society of Applied Physics