23.5%-efficient silicon heterojunction silicon solar cell using molybdenum oxide as hole-selective contact
TL;DR: In this paper, the influence of the MoOx and intrinsic a-Si:H thicknesses on current-voltage properties and discuss transport and performance-loss mechanisms is discussed. But the authors focus on the front-side hole-selective layer.
About: This article is published in Nano Energy.The article was published on 2020-04-01 and is currently open access. It has received 163 citations till now. The article focuses on the topics: Amorphous silicon & Passivation.
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TL;DR: In this paper, the development status of high-efficiency crystalline silicon (c-Si) heterojunction solar cells, from the materials to devices, mainly including hydrogenated amorphous silicon (a-Si:H) based silicon heterjunction technology, polycrystalline silicon based carrier selective passivating contact technology, metal compounds and organic materials based dopant-free contact technology are reviewed.
Abstract: Photovoltaic (PV) technology offers an economic and sustainable solution to the challenge of increasing energy demand in times of global warming. The world PV market is currently dominated by the homo-junction crystalline silicon (c-Si) PV technology based on high temperature diffused p-n junctions, featuring a low power conversion efficiency (PCE). Recent years have seen the successful development of Si heterojunction technologies, boosting the PCE of c-Si solar cells over 26%. This article reviews the development status of high-efficiency c-Si heterojunction solar cells, from the materials to devices, mainly including hydrogenated amorphous silicon (a-Si:H) based silicon heterojunction technology, polycrystalline silicon (poly-Si) based carrier selective passivating contact technology, metal compounds and organic materials based dopant-free passivating contact technology. The application of silicon heterojunction solar cells for ultra-high efficiency perovskite/c-Si and III-V/c-Si tandem devices is also reviewed. In the last, the perspective, challenge and potential solutions of silicon heterojunction solar cells, as well as the tandem solar cells are discussed.
112 citations
TL;DR: In this paper , the authors survey the key changes related to materials and industrial processing of silicon PV components and discuss what it will take for other PV technologies to compete with silicon on the mass market.
Abstract: Crystalline silicon (c-Si) photovoltaics has long been considered energy intensive and costly. Over the past decades, spectacular improvements along the manufacturing chain have made c-Si a low-cost source of electricity that can no longer be ignored. Over 125 GW of c-Si modules have been installed in 2020, 95% of the overall photovoltaic (PV) market, and over 700 GW has been cumulatively installed. There are some strong indications that c-Si photovoltaics could become the most important world electricity source by 2040–2050. In this Review, we survey the key changes related to materials and industrial processing of silicon PV components. At the wafer level, a strong reduction in polysilicon cost and the general implementation of diamond wire sawing has reduced the cost of monocrystalline wafers. In parallel, the concentration of impurities and electronic defects in the various types of wafers has been reduced, allowing for high efficiency in industrial devices. Improved cleanliness in production lines, increased tool automation and improved production technology and cell architectures all helped to increase the efficiency of mainstream modules. Efficiency gains at the cell level were accompanied by an increase in wafer size and by the introduction of advanced assembly techniques. These improvements have allowed a reduction of cell-to-module efficiency losses and will accelerate the yearly efficiency gain of mainstream modules. To conclude, we discuss what it will take for other PV technologies to compete with silicon on the mass market. Crystalline silicon solar cells are today’s main photovoltaic technology, enabling the production of electricity with minimal carbon emissions and at an unprecedented low cost. This Review discusses the recent evolution of this technology, the present status of research and industrial development, and the near-future perspectives.
67 citations
TL;DR: Kohler et al. as mentioned in this paper proposed a passivating contact based on a double layer of nanocrystalline silicon carbide that overcomes the trade-offs of conductivity, defect passivation and optical transparency.
Abstract: A highly transparent passivating contact (TPC) as front contact for crystalline silicon (c-Si) solar cells could in principle combine high conductivity, excellent surface passivation and high optical transparency. However, the simultaneous optimization of these features remains challenging. Here, we present a TPC consisting of a silicon-oxide tunnel layer followed by two layers of hydrogenated nanocrystalline silicon carbide (nc-SiC:H(n)) deposited at different temperatures and a sputtered indium tin oxide (ITO) layer (c-Si(n)/SiO2/nc-SiC:H(n)/ITO). While the wide band gap of nc-SiC:H(n) ensures high optical transparency, the double layer design enables good passivation and high conductivity translating into an improved short-circuit current density (40.87 mA cm−2), fill factor (80.9%) and efficiency of 23.99 ± 0.29% (certified). Additionally, this contact avoids the need for additional hydrogenation or high-temperature postdeposition annealing steps. We investigate the passivation mechanism and working principle of the TPC and provide a loss analysis based on numerical simulations outlining pathways towards conversion efficiencies of 26%. Passivating contacts hold promise for silicon solar cells yet the simultaneous optimization of conductivity, defect passivation and optical transparency remains challenging. Now Kohler et al. devise a passivating contact based on a double layer of nanocrystalline silicon carbide that overcomes these trade-offs.
65 citations
01 Nov 2021
TL;DR: In this article, the authors highlighted the contribution of Mohammed bin Rashid Al Maktoum (MBR) Solar Park in the United Arab Emirates to achieving the sustainable development goals (SDGs).
Abstract: With the fast growth of the global economy, energy supply and demand have a strong impact on social, economic, and environmental aspects. As a consequence, this has pushed the decision-makers to formulate objectives, guiding economic policies toward sustainable goals. The process is known as Sustainable Development Goals (SDGs) that have been proposed by the United Nations. This being said, the energy sector is a vital domain with a vast potential for improvments in terms of technologies and ligistalations. Solar energy is among the most efficient solutions proposed to reduce the economic and environmental footprints of energy. In this frame, the current paper aims to localize solar energy within SDGs and analyze the contribution of the solar energy towards the achievement of the SDGs. Moreover, the current work highlights the contributions of Mohammed bin Rashid Al Maktoum (MBR) Solar Park in the United Arab Emirates to achieving the SDGs. Indeed, the MBR Solar Park concept offers valuable insights of environmental impacts by deploying clean and affordable energy sources in place of conventional fossil fuel power plants that are still heavily used in the region. The MBR Solar Park operation has already mitigated 6.5 million tonnes of carbon dioxide equivalent and this number will likely rise when all phases are installed and operational. Moreover, it has been shown that MBR Solar Park achieve several SDGs such SDG 8: decent work and economic growth, SDG 9: industry, innovation and infrastructure, SDG 11: sustainable cities and communities, and SDG 15: life on land.
62 citations
TL;DR: In this paper, De Bastiani et al. presented a contactless capacitance-voltage (C-V ) measurement with a competitive grant from the National Natural Science Foundation of China (No. 91833303).
Abstract: The work presented in this publication was financially supported by King Abdullah University of Science and Technology (KAUST), through the Competitive Research Grant. B.S. and X.Z. acknowledge the National Natural Science Foundation of China (No. 91833303). The authors would like to thank Dr. Michele De Bastiani and Dr. Thomas Allen in KAUST for helping the device fabrication and Dr. Ziv Hameiri (University of New South Wales) for conducting the contactless capacitance–voltage (C–V ) measurements. The authors also thank Heno Hwang, scientific illustrator at KAUST, for producing Figure 5a.
57 citations
References
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TL;DR: In this paper, a silicon heterojunction with interdigitated back contacts was presented, achieving an efficiency of 26.3% and a detailed loss analysis to guide further developments.
Abstract: The efficiency of silicon solar cells has a large influence on the cost of most photovoltaics panels. Here, researchers from Kaneka present a silicon heterojunction with interdigitated back contacts reaching an efficiency of 26.3% and provide a detailed loss analysis to guide further developments.
2,052 citations
TL;DR: An overview of TMO-based device architectures ranging from transparent OLEDs to tandem OPV cells is given, and various TMO film deposition methods are reviewed, addressing vacuum evaporation and recent approaches for solution-based processing.
Abstract: During the last few years, transition metal oxides (TMO) such as molybdenum tri-oxide (MoO3), vanadium pent-oxide (V2O5) or tungsten tri-oxide (WO3) have been extensively studied because of their exceptional electronic properties for charge injection and extraction in organic electronic devices. These unique properties have led to the performance enhancement of several types of devices and to a variety of novel applications. TMOs have been used to realize efficient and long-term stable p-type doping of wide band gap organic materials, charge-generation junctions for stacked organic light emitting diodes (OLED), sputtering buffer layers for semi-transparent devices, and organic photovoltaic (OPV) cells with improved charge extraction, enhanced power conversion efficiency and substantially improved long term stability. Energetics in general play a key role in advancing device structure and performance in organic electronics; however, the literature provides a very inconsistent picture of the electronic structure of TMOs and the resulting interpretation of their role as functional constituents in organic electronics. With this review we intend to clarify some of the existing misconceptions. An overview of TMO-based device architectures ranging from transparent OLEDs to tandem OPV cells is also given. Various TMO film deposition methods are reviewed, addressing vacuum evaporation and recent approaches for solution-based processing. The specific properties of the resulting materials and their role as functional layers in organic devices are discussed.
1,023 citations
TL;DR: A universal energy-alignment trend is observed for a set of transition-metal oxides--representing a broad diversity in electronic properties--with several organic semiconductors, demonstrating that, despite the variance in their electronic properties, oxide energy alignment is governed by one driving force: electron-chemical-potential equilibration.
Abstract: Transition-metal oxides improve power conversion efficiencies in organic photovoltaics and are used as low-resistance contacts in organic light-emitting diodes and organic thin-film transistors. What makes metal oxides useful in these technologies is the fact that their chemical and electronic properties can be tuned to enable charge exchange with a wide variety of organic molecules. Although it is known that charge exchange relies on the alignment of donor and acceptor energy levels, the mechanism for level alignment remains under debate. Here, we conclusively establish the principle of energy alignment between oxides and molecules. We observe a universal energy-alignment trend for a set of transition-metal oxides--representing a broad diversity in electronic properties--with several organic semiconductors. The trend demonstrates that, despite the variance in their electronic properties, oxide energy alignment is governed by one driving force: electron-chemical-potential equilibration. Using a combination of simple thermodynamics, electrostatics and Fermi statistics we derive a mathematical relation that describes the alignment.
865 citations
08 Mar 2012
TL;DR: Silicon heterojunction solar cells as mentioned in this paper consist of thin amorphous silicon layers deposited on crystalline silicon wafers, which enables energy conversion efficiencies above 20% at the industrial production level.
Abstract: Silicon heterojunction solar cells consist of thin amorphous silicon layers deposited on crystalline silicon wafers. This design enables energy conversion efficiencies above 20% at the industrial production level. The key feature of this technology is that the metal contacts, which are highly recombination active in traditional, diffused-junction cells, are electronically separated from the absorber by insertion of a wider bandgap layer. This enables the record open-circuit voltages typically associated with heterojunction devices without the need for expensive patterning techniques. This article reviews the salient points of this technology. First, we briefly elucidate device characteristics. This is followed by a discussion of each processing step, device operation, and device stability and industrial upscaling, including the fabrication of solar cells with energy-conversion efficiencies over 21%. Finally, future trends are pointed out. (orig.)
765 citations