Rapid mitigation of carrier-induced degradation in commercial silicon solar cells

Hallam, Brett; Chen, Ran; Wang, Sisi; Ji, Jingjia; Mai, Linh; Abbott, Malcolm; Payne, D.N.; Kim, Moonyong; Chen, Daniel; Chong, Chee Mun; Wenham, Stuart

doi:10.7567/jjap.56.08mb13

Cited by 29 publications

(23 citation statements)

References 50 publications

(66 reference statements)

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“…[110] In contrast, by accelerating the defect formation rate using high-intensity illumination, a substantially higher temperature can be used, which results in a further reduction in the time to form the defects. [72,98,100] Using such a process, B-O defects can be completely formed and passivated on finished industrial screen-printed solar cells in less than 8 s, [72,100,113] which can improve cell performance of industrial cells in the vicinity of 1 % absolute. [113] This has seen the development of new halogen-, light-emitting diode (LED)-, and laser-based industrial advanced hydrogenation tools for the mitigation of B-O-related degradation.…”

Section: Hydrogenation Of Carrier-induced Defectsmentioning

confidence: 99%

“…[72,98,100] Using such a process, B-O defects can be completely formed and passivated on finished industrial screen-printed solar cells in less than 8 s, [72,100,113] which can improve cell performance of industrial cells in the vicinity of 1 % absolute. [113] This has seen the development of new halogen-, light-emitting diode (LED)-, and laser-based industrial advanced hydrogenation tools for the mitigation of B-O-related degradation. [113] An example showing the impact of advanced hydrogenation processes for eliminating B-O-related degradation is shown in Table 2.…”

Section: Hydrogenation Of Carrier-induced Defectsmentioning

confidence: 99%

“…[113] This has seen the development of new halogen-, light-emitting diode (LED)-, and laser-based industrial advanced hydrogenation tools for the mitigation of B-O-related degradation. [113] An example showing the impact of advanced hydrogenation processes for eliminating B-O-related degradation is shown in Table 2. The cells that received an AHP process to eliminate B-O-related carrier-induced degradation show a higher efficiency (20.54 %) after the AHP and subsequent accelerated stability test [98] compared with the initial efficiency (20.11 %).…”

Section: Hydrogenation Of Carrier-induced Defectsmentioning

confidence: 99%

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Overcoming the Challenges of Hydrogenation in Silicon Solar Cells

et al. 2018

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The challenges of passivating defects in silicon solar cells using hydrogen atoms are discussed. Atomic hydrogen is naturally incorporated into conventional silicon solar cells through the deposition of hydrogen-containing dielectric layers and the metallisation firing process. The firing process can readily passivate certain structural defects such as grain boundaries. However, the standard hydrogenation processes are ineffective at passivating numerous defects in silicon solar cells. This difficulty can be attributed to the atomic hydrogen naturally occupying low-mobility and low-reactivity charge states, or the thermal dissociation of hydrogen–defect complexes. The concentration of the highly mobile and reactive neutral-charge state of atomic hydrogen can be enhanced using excess carriers generated by light. Additional low-temperature hydrogenation processes implemented after the conventional fast-firing hydrogenation process are shown to improve the passivation of difficult structural defects. For process-induced defects, careful attention must be paid to the process sequence to ensure that a hydrogenation process is included after the defects are introduced into the device. Defects such as oxygen precipitates that form during high-temperature diffusion and oxidation processes can be passivated during the subsequent dielectric deposition and high-temperature firing process. However, for laser-based processes performed after firing, an additional hydrogenation process should be included after the introduction of the defects. Carrier-induced defects are even more challenging to passivate, and advanced hydrogenation methods incorporating minority carrier injection must be used to induce defect formation first, and, second, provide charge state manipulation to enable passivation. Doing so can increase the performance of industrial p-type Czochralski solar cells by 1.1 % absolute when using a new commercially available laser-based advanced hydrogenation tool.

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Section: Hydrogenation Of Carrier-induced Defectsmentioning

confidence: 99%

Section: Hydrogenation Of Carrier-induced Defectsmentioning

confidence: 99%

Section: Hydrogenation Of Carrier-induced Defectsmentioning

confidence: 99%

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Overcoming the Challenges of Hydrogenation in Silicon Solar Cells

et al. 2018

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“…Currently, most tools are using intensities in the range of 5-20 suns [144][145][146][147]. The illumination intensities used leads to industrial belt-furnace based tools typically requiring processing times of 25-45 s per wafer for the process.…”

Section: Lid Mitigation During Cell Fabricationmentioning

confidence: 99%

“…This illuminated process can be achieved during the cool-down section of the high-temperature co-firing process, or as a separate thermal process after co-firing. Several companies, including Centrotherm (Blaubeuren, Germany), Despatch Industries (Mineapolis, MN, USA), Schmid (Freudenstadt, Germany), Asia Neo Tech (Taoyuan City, Taiwan), DR Laser (Wuhan, China) and Folungwin (Dongguan Shi, China) have tools available for LID mitigation that can reduce the extent of LID by approximately 75-80% [144][145][146][147]. For tools with LID mitigation processes integrated into tools for the fast-firing of the metallisation contacts, any potential changes to belt speed resulting from the requirements of future pastes could directly impact B-O LID mitigation.…”

Section: Lid Mitigation During Cell Fabricationmentioning

confidence: 99%

Eliminating Light-Induced Degradation in Commercial p-Type Czochralski Silicon Solar Cells

et al. 2017

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This paper discusses developments in the mitigation of light-induced degradation caused by boron-oxygen defects in boron-doped Czochralski grown silicon. Particular attention is paid to the fabrication of industrial silicon solar cells with treatments for sensitive materials using illuminated annealing. It highlights the importance and desirability of using hydrogen-containing dielectric layers and a subsequent firing process to inject hydrogen throughout the bulk of the silicon solar cell and subsequent illuminated annealing processes for the formation of the boron-oxygen defects and simultaneously manipulate the charge states of hydrogen to enable defect passivation. For the photovoltaic industry with a current capacity of approximately 100 GW peak, the mitigation of boron-oxygen related light-induced degradation is a necessity to use cost-effective B-doped silicon while benefitting from the high-efficiency potential of new solar cell concepts.

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Defect engineering of p‐type silicon heterojunction solar cells fabricated using commercial‐grade low‐lifetime silicon wafers

Chen

Kim

Shi

et al. 2019

Progress in Photovoltaics

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In this work, we integrate defect engineering methods of gettering and hydrogenation into silicon heterojunction solar cells fabricated using low-lifetime commercial-grade p-type Czochralski-grown monocrystalline and high-performance multicrystalline wafers. We independently assess the impact of gettering on the removal of bulk impurities such as iron as well as the impact of hydrogenation on the passivation of grain boundaries and B-O defects. Furthermore, we report for the first time the susceptibility of heterojunction devices to light-and elevated temperature-induced degradation and investigate the onset of such degradation during device fabrication. Lastly, we demonstrate solar cells with independently verified 1-sun open-circuit voltages of 707 and 702 mV on monocrystalline and multicrystalline silicon wafers, respectively, with a starting bulk minority-carrier lifetime below 40 microseconds. These remarkably high opencircuit voltages reveal the potential of inexpensive low-lifetime p-type silicon wafers for making devices with efficiencies without needing to shift towards n-type substrates.

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Rapid mitigation of carrier-induced degradation in commercial silicon solar cells

Cited by 29 publications

References 50 publications

Overcoming the Challenges of Hydrogenation in Silicon Solar Cells

Overcoming the Challenges of Hydrogenation in Silicon Solar Cells

Eliminating Light-Induced Degradation in Commercial p-Type Czochralski Silicon Solar Cells

Defect engineering of p‐type silicon heterojunction solar cells fabricated using commercial‐grade low‐lifetime silicon wafers

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