Katarina Kovačević, Yifeng Zhao, Paul Procel, Liqi Cao, Luana Mazzarella, Olindo Isabella
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引用次数: 0
Abstract
The fabrication process of interdigitated-back-contacted silicon heterojunction (IBC-SHJ) solar cells has been significantly simplified with the development of the so-called tunnel-IBC architecture. This architecture utilizes a highly conductive (p)-type nanocrystalline silicon (nc-Si:H) layer deposited over the full substrate area comprising pre-patterned (n)-type nc-Si:H fingers. In this context, the (p)-type nc-Si:H layer is referred to as blanket layer. As both electrodes are connected to the same blanket layer, the high lateral conductivity of (p)nc-Si:H layer can potentially lead to relatively low shunt resistance in the device, thus limiting the performance of such solar cells. To overcome such limitation, we introduce a thin (<2 nm) full-area molybdenum oxide (MoOx) layer as an alternative to the (p)nc-Si:H blanket layer. We demonstrate that the use of such a thin MoOx minimizes the shunting losses thanks to its low lateral conductivity while preserving the simplified fabrication process. In this process, a novel (n)-type nc-Si:H/MoOx electron collection contact stack is implemented within the proposed solar cell architecture. We assess its transport mechanisms via electrical simulations showing that electron transport, unlike in the case of tunnel-IBC, occurs in the conduction band fully. Moreover, the proposed contact stack is evaluated in terms of contact resistivity and integrated into a proof-of-concept front/back-contacted (FBC) SHJ solar cells. Contact resistivity as low as 100 mΩcm2 is achieved, and fabricated FBC-SHJ solar cells obtain a fill factor above 81.5% and open-circuit voltage above 705 mV. Lastly, the IBC-SHJ solar cells featuring the MoOx blanket layer are fabricated, exhibiting efficiencies up to 21.14% with high shunt resistances above 150 kΩcm2. Further optimizations in terms of layer properties and fabrication process are proposed to improve device performance and realize the efficiency potential of our novel IBC-SHJ solar cell architecture.
期刊介绍:
Progress in Photovoltaics offers a prestigious forum for reporting advances in this rapidly developing technology, aiming to reach all interested professionals, researchers and energy policy-makers.
The key criterion is that all papers submitted should report substantial “progress” in photovoltaics.
Papers are encouraged that report substantial “progress” such as gains in independently certified solar cell efficiency, eligible for a new entry in the journal''s widely referenced Solar Cell Efficiency Tables.
Examples of papers that will not be considered for publication are those that report development in materials without relation to data on cell performance, routine analysis, characterisation or modelling of cells or processing sequences, routine reports of system performance, improvements in electronic hardware design, or country programs, although invited papers may occasionally be solicited in these areas to capture accumulated “progress”.