Hydrogen-Induced Degradation

Wenham, Alison; Wenham, Stuart; Chen, Ran; Chen, Daniel; Hallam, Brett; Payne, D.N.; Fung, Tsun Hang; Kim, Moonyong; Liu, Shaoyang; Wang, Sisi; Kim, Kyung; Samadi, Aref; Sen, Chandany; Vargas, Carlos Arturo Parra; Varshney, Utkarshaa; Stefani, Bruno Vicari; Hamer, Phillip; Bourret‐Sicotte, Gabrielle; Nampalli, Nitin; Hameiri, Ziv; Chong, Chee Mun; Abbott, Malcolm

doi:10.1109/pvsc.2018.8548100

Cited by 26 publications

(16 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is a common understanding that hydrogen plays an important role for the LeTID defect reaction [4], [9], [12], [13], [20]- [26]. Therefore, we propose a defect reaction involving hydrogen that could explain LeTID.…”

mentioning

confidence: 85%

Temporary Recovery of the Defect Responsible for Light- and Elevated Temperature-Induced Degradation: Insights Into the Physical Mechanisms Behind LeTID

Kwapil

Schön

Niewelt

et al. 2020

IEEE J. Photovoltaics

View full text Add to dashboard Cite

The effect of light-and elevated temperature-induced degradation (LeTID) can be nonpermanently reversed by charge carrier injection below the degradation temperature (commonly used degradation temperatures are above ∼70°C). In this study, we show that the rate of temporary recovery depends strongly on the excess carrier density. We observe that the order of the reaction changes from pseudo-zero to first with increasing injection. The rate decreases slightly with increasing temperature. Since the samples can go through multiple degradation/recovery cycles without distinct changes in the degradation kinetics, the experimentally accessible recovered and degraded states are interpreted as manifestations of the equilibrium concentrations of the defect responsible for LeTID at different temperatures. Based on our observations, we argue that the process underlying LeTID degradation is the dissociation of a precursor rather than an association of two or more components. In light of the relation between LeTID susceptibility and bulk hydrogen concentration, we hypothesize that the LeTID precursor dissociates into the LeTID defect and monatomic hydrogen. Numerical simulations of the coupled rate equations including hydrogen interactions well reproduce the experimental observations; according to these results, the presence of a sink for the atomic hydrogen such as dopant atoms is paramount for the LeTID degradation. Index Terms-Degradation, Defect reactions, light-and elevated temperature-induced degradation (LeTID), model, silicon defects. I. INTRODUCTION A FTER the first description of the phenomenon later termed light-and elevated temperature-induced degradation (LeTID) [1], extensive research has been conducted on the influences determining the LeTID extent and kinetics. Noting the

show abstract

mentioning

confidence: 85%

Temporary Recovery of the Defect Responsible for Light- and Elevated Temperature-Induced Degradation: Insights Into the Physical Mechanisms Behind LeTID

Kwapil

Schön

Niewelt

et al. 2020

IEEE J. Photovoltaics

View full text Add to dashboard Cite

show abstract

“…Table 4 summarizes the known and most prominent degradation mechanisms caused by either the formation of BO (boron-oxygen) complexes [25], hydrogenation of metallic impurities [26], or depassivation of PERC s rear side [27]. Adapting the c-Si material and solar cell process according to the properties as described in Table 4 can minimize the degradation.…”

Section: Letid In Bifacial Cells/modulesmentioning

confidence: 99%

Bifacial Photovoltaics 2021: Status, Opportunities and Challenges

Kopecek

Libal

2021

Energies

View full text Add to dashboard Cite

In this paper we summarize the status of bifacial photovoltaics (PV) and explain why the move to bifaciality is unavoidable when it comes to e.g., lowest electricity generation costs or agricultural PV (AgriPV). Bifacial modules—those that are sensitive to light incident from both sides—are finally available at the same price per watt peak as their standard monofacial equivalents. The reason for this is that bifacial solar cells are the result of an evolution of crystalline Si PV cell technology and, at the same time, module producers are increasingly switching to double glass modules anyway due to the improved module lifetimes, which allows them to offer longer product warrantees. We describe the general properties of the state-of-the-art bifacial module, review the different bifacial solar cells and module technologies available on the market, and summarize their average costs. Adding complexity to a module comes with the increase of possible degradation mechanisms, requiring more thorough testing, e.g., for rear side PID (Potential Induced Degradation). We show that with the use of bifacial modules in fixed tilt systems, gains in annual energy yield of up to 30% can be expected compared to the monofacial equivalent. With the combination of bifacial modules in simple single axis tracking systems, energy yield increases of more than 40% can be expected compared to fixed tilt monofacial installations. Rudimentary simulations of bifacial systems can be performed with commercially available programs. However, when more detailed and precise simulations are required, it is necessary to use more advanced programs such as those developed at several institutes. All in all, as bifacial PV—being the most cost-effective PV solution—is now becoming also bankable, it is becoming the overall best technology for electricity generation.

show abstract

“…Although n-type TOPCon solar cells do not suffer BO LID, several reports have shown the presence of light-and elevated temperature-induced degradation (LeTID) in n-type wafers. [13][14][15] Additionally, several studies have also demonstrated a firinginduced degradation in the tunnelling oxide/doped polysilicon passivation scheme employed in TOPCon solar cells. 16,17 The incorporation of a hydrogenation step is critical to achieve the required chemical passivation for the tunnelling oxide, polysilicon contact.…”

mentioning

confidence: 99%

“…This approach is often referred to as an 'advanced hydrogenation process' and involves carrier injection, either via illumination or direct current injection. 15 Modulating the carrier density and temperature can alter the charge state of hydrogen in silicon. 15 This alteration of the charge state can vastly impact its ability to passivate defects.…”

mentioning

confidence: 99%

See 1 more Smart Citation

24.58% efficient commercial n‐type silicon solar cells with hydrogenation

Chen

Wright

Chen

et al. 2021

Progress in Photovoltaics

Self Cite

View full text Add to dashboard Cite

Tunnelling oxide passivated contact (TOPCon) solar cells are gaining significant commercial interest, due to the potential for high efficiency. Industrially, this passivated contact scheme is typically coupled with an n-type Czochralski (Cz) wafer. JinkoSolar Holding Co., Ltd. is one of the leading manufacturers that are producing n-type TOPCon solar cells (referred to as 'HOT' cells) on a commercial scale. In this work, the influence of a post-cell hydrogenation step, using illumination from an LED light source, on the performance and stability of n-type TOPCon solar cells is investigated.The incorporation of this additional hydrogenation treatment led to an average efficiency enhancement of 0.64% abs on a batch of 50 cells made in an industrial environment. This significant improvement was caused by a 6.9 mV and 1.04% abs increase in open-circuit voltage (V OC ) and fill factor (FF), respectively. We also assessed the stability and found almost no light-and elevated temperature-induced degradation (LeTID) in hydrogenated n-type TOPCon cells. Testing at 70 ± 5 C under 1-sun illumination revealed that the maximum degradation is limited to 0.06% rel .Following further stability testing, the efficiency increased beyond the initial value, up to 0.4% rel increase after 120 h. By incorporating this hydrogenation process into the production, an average line efficiency of 24.08% and V OC of 707.5 mV was achieved. The champion cell from the batch displayed an efficiency of 24.58%, as certified by measurement at the Chinese Academy of Sciences.

show abstract

Hydrogen-Induced Degradation

Cited by 26 publications

References 50 publications

Temporary Recovery of the Defect Responsible for Light- and Elevated Temperature-Induced Degradation: Insights Into the Physical Mechanisms Behind LeTID

Temporary Recovery of the Defect Responsible for Light- and Elevated Temperature-Induced Degradation: Insights Into the Physical Mechanisms Behind LeTID

Bifacial Photovoltaics 2021: Status, Opportunities and Challenges

24.58% efficient commercial n‐type silicon solar cells with hydrogenation

Contact Info

Product

Resources

About