Temperature and Humidity Stable Alkali/Alkaline‐Earth Metal Carbonates as Electron Heterocontacts for Silicon Photovoltaics

Wan, Yimao; Bullock, James; Hettick, Mark; Xu, Zhaoran; Samundsett, Christian; Yan, Donghang; Peng, Jun; Ye, Jichun; Javey, Ali; Cuevas, Andrés

doi:10.1002/aenm.201800743

Cited by 39 publications

(44 citation statements)

References 20 publications

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“…104 Molybdenum oxide in particular has recently been integrated into PRC and full-area contact cells attaining PCEs of 20.6% and 23.5%. 105,106 In addition to metal oxides, a range of other metal compounds have been explored as contact materials for c-Si solar cells, including sulphides, 107 nitrides, 108,109 phosphides, 110 iodides, 111 carbonates, 112 and fluorides. 35 Of note among these are the alkali and alkaline earth metal fluorides utilised in electron extraction, including LiF, and MgF2.…”

Section: Mis Passivating Contactsmentioning

confidence: 99%

Passivating contacts for crystalline silicon solar cells

et al. 2019

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The global photovoltaic (PV) market is dominated by crystalline silicon (c-Si) based technologies with heavily doped, directly metallised contacts. Recombination of photogenerated electrons and holes at the contact regions is increasingly constraining the power conversion efficiencies of these devices as other performance-limiting energy losses are overcome. To move forward, c-Si PV technologies must implement alternative contacting approaches. Passivating contacts, which incorporate thin films within the contact structure that simultaneously supress recombination and promote charge carrier selectivity, are a promising next step for the mainstream c-Si PV industry. In this work we review the fundamental physical processes governing contact formation in c-Si. In doing so we identify the role passivating contacts play in increasing c-Si solar cell efficiencies beyond the limitations imposed by heavy doping and direct metallisation. Strategies towards the implementation of passivating contacts in industrial environments are discussed.

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Section: Mis Passivating Contactsmentioning

confidence: 99%

Passivating contacts for crystalline silicon solar cells

et al. 2019

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“…Finally, we realize a 19.5%-efficient c-Si solar cell by using an AZO/Al stack (on top of a passivating i a-Si:H layer) as electron-selective contact, which is the highest efficiency among the solar cells using ZnO as electron-selective film. In addition, it is worth mentioning that the previously successful electron-selective films are mainly made by either thermal evaporation [6,8,9,12] or atomic layer deposition [5,10,11]. Here our study firstly shows that magnetron sputtering is also a feasible method to fabricate efficient electron-selective films.…”

Section: Introductionmentioning

confidence: 64%

“…have attracted a significant interest as these contacts have the potential to further improve the cell performance by using more transparent or conducting layers, and to simplify the fabrication process. Until now, various materials have been demonstrated as effective electron-selective layers, including LiFx [8], MgFx [9], MgOx [6], TiOx [4,5], TaOx [11], TaNx [10], alkali/alkaline-earth metal carbonates [12], and their combinations [13], in some cases combined with intrinsic a-Si:H (i a-Si:H) for passivation.…”

Section: Introductionmentioning

confidence: 99%

Exploring co-sputtering of ZnO:Al and SiO2 for efficient electron-selective contacts on silicon solar cells

Zhong

Morales‐Masis

Mews

et al. 2019

Solar Energy Materials and Solar Cells

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In recent years, considerable efforts have been devoted to developing novel electron-selective materials for crystalline Si (c-Si) solar cells with the attempts to simplify the fabrication process and improve efficiency. In this study, ZnO:Al (AZO) is co-sputtered with SiO2 to form AZO:SiO2 films with different SiO2 content. These nanometer-scale films, deposited on top of thin intrinsic hydrogenated amorphous silicon films and capped with low-work-function metal (such as Al and Mg), are demonstrated to function effectively as electron-selective contacts in c-Si solar cells. On the one hand, AZO:SiO2 plays an important role in such electron-selective contact and its thickness is a critical parameter, thickness of 2 nm showing the best. On the other hand, at the optimal thickness of AZO:SiO2, the open circuit voltage (VOC) of the solar cells is found to be relatively insensitive to either the work function or the band gap of AZO:SiO2. Whereas, regarding the fill factor (FF), AZO without SiO2 content exhibits to be the optimal choice. By using AZO/Al as electron-selective contact, we successfully realize a 19.5%-efficient solar cell with VOC over 700 mV and FF around 75%, which is the best result among c-Si solar cells using ZnO as electron-selective contact. Also, this work implies that efficient carrier-selective film can be made by magnetron sputtering method.

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“…Therefore, solar cells using MoO x as HTL at the sunward side exhibit a higher short‐circuit current density ( J SC ) . As ETLs, LiF x , MgO x , MgF x , TiO x , TaO x , TaN x , or alkali/alkaline‐earth metal carbonates, combined with a low‐work‐function metal such as Al, Mg and Ca have been demonstrated to yield efficient electron‐selective contacts in c‐Si solar cells. Generally, these contacts are placed at the rear side of solar cells.…”

Section: Introductionmentioning

confidence: 96%

Mitigating Plasmonic Absorption Losses at Rear Electrodes in High‐Efficiency Silicon Solar Cells Using Dopant‐Free Contact Stacks

Zhong

Dréon

Jeangros

et al. 2019

Adv Funct Materials

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Although charge-carrier selectivity in conventional crystalline silicon (c-Si) solar cells is usually realized by doping Si, the presence of dopants imposes inherent performance limitations due to parasitic absorption and carrier recombination. The development of alternative carrier-selective contacts, using non-Si electron and hole transport layers, has the potential to overcome such drawbacks and simultaneously reduce the cost and/or simplify the fabrication process of c-Si solar cells. Nevertheless, devices relying on such non-Si contacts with power conversion efficiencies (PCEs) that rival their classical counterparts are yet to be demonstrated. In this study, one key element is brought forward toward this demonstration by incorporating low-pressure chemical vapor deposited ZnO as the electron transport layer in c-Si solar cells. Placed at the rear of the device, it is found that rather thick (75 nm) ZnO film capped with LiF x /Al simultaneously enables efficient electron selectivity and suppression of parasitic infrared absorption. Next, these electron-selective contacts are integrated in c-Si solar cells with MoO x -based hole-collecting contacts at the device front to realize full-area dopant-freecontact solar cells. In the proof-of-concept device, a PCE as high as 21.4% is demonstrated, which is a record for this novel device class and is at the level of conventional industrial solar cells.

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Temperature and Humidity Stable Alkali/Alkaline‐Earth Metal Carbonates as Electron Heterocontacts for Silicon Photovoltaics

Cited by 39 publications

References 20 publications

Passivating contacts for crystalline silicon solar cells

Passivating contacts for crystalline silicon solar cells

Exploring co-sputtering of ZnO:Al and SiO2 for efficient electron-selective contacts on silicon solar cells

Mitigating Plasmonic Absorption Losses at Rear Electrodes in High‐Efficiency Silicon Solar Cells Using Dopant‐Free Contact Stacks

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