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The amount of solar PV manufactured over the next ten years and beyond is expected to rapidly increase to help curb global CO₂ emissions. This rapid expansion will require further considerations be given to the consumption of the constituent materials that go into making commercial solar panels. New research from UNSW has shown that the consumption of materials, in particular silver, indium and bismuth, will place limitations on the ability for PV manufacturing to expand at the required rate. The authors also suggest that tandem architectures can help reduce material consumption, as they have lower power losses due to series resistance compared with single junction approaches. 

Read more at ‘PV Magazine‘

A heliostat uses an array of movable mirrors to redirect the suns’ rays. While typically used in a large solar power plant to concentrate sunlight, this approach is being adapted to the built environment, to help redistribute light to dim urban areas. A new design in Rhodes uses movable mirrors on the roof of a 39-story building to bounce light to an array of reflectors, which then shines the light back to the street. As the buildings in our cities grow taller and taller, this could provide a potential solution to shading. 

Read more at ‘ABC News‘

Australian company Sundrive achieved a world record efficiency of 25.54% for a commercial size silicon solar cell, improving on the previous record of 25.26% held by LONGi. One fundamental difference with previous record cells is that Sundrive are using a technique called ‘copper plating’ to form the metal contacts, as opposed to the traditional screen printing of silver currently used in industry. The predicted rapid expansion of the PV industry over the coming decade has raised concerns over the consumption of silver for metal contacts, which has made the switch to copper contacts more appealing. This demonstration of a world record cell efficiency using copper represents a major breakthrough for the technology. 

Read more at ‘Renew Economy‘

Two identical office buildings side by side in Sydney’s Barangaroo provided a perfect opportunity for solar energy researchers to test a long-held hunch.

The answer, as it turned out, was yes.

The study was led by Peter Irga from the University of Technology Sydney and funded by the City of Sydney Council.

“For the first time we had the opportunity to compare these two buildings against each other,” Dr Irga said.

Read more at ‘ABC News‘

UNSW Engineering Professor Thorsten Trupke has won the internationally coveted IEEE William Cherry Award. The award recognises outstanding contributions to photovoltaic science and technology, by an individual who has devoted part of their professional life to the cause.

The award is named in honour of the late William R. Cherry, a founder of the photovoltaic community and pioneer of using photovoltaic systems for terrestrial applications.

Read more at ‘UNSW Newsroom‘

The PV industry continuous to push the efficiency of industrial silicon solar cells. LONGI was able to improve the world-record efficiency of three types of solar cells with at least one passivating contacts. They improved the efficiency of both n-type and p-type solar cells with a TOPCon electron contact to 25.21% and 25.02%, respectively. In addition, they demonstrated a 25.26% efficiency for a silicon heterojunction solar cell. These are remarkable efficiencies considering that these were produced on full industrial sized silicon wafers using pilot production equipment. Both TOPCon and silicon heterojunction solar cells are intensively investigated for near-future high-volume manufacturing.

Read more at ‘LONGI Solar‘

UNSW Scientia Professor Martin Green describes how photovoltaic solar power went from being outrageously expensive to “insanely cheap”. His team at UNSW laid many of the foundations for this incredible cost reduction that has been achieved through international collaboration and partnership. The PVSEC conferences have served as an important forum for this research witnessing and fitting that in 2021, the conference returns to Sydney where the latest scientific research and industrial developments will be announced. Professor Green will deliver the opening keynote address at PVSEC-31, 11am December 13th 2021.

Read more at ‘The Guardian‘

In April 2017, French renewable energy developer Tenergie commissioned its first photovoltaic greenhouse based on its proprietary technology Tenairlux, in Mallemort, in the Bouches-du-Rhône region of southern France. The plant was built with 265 W panels and has an installed power of 2.1 MW.

“Four years after the commissioning of this 33,000m² greenhouse, our feedback is positive, with a yield of four tons/hectare for this first year of growing green asparagus from Provence, after a period of diversified cultivation including zucchini, turnips, [and] sweet potatoes during the first three years and a production of 3.1 GWh of green electricity, which is the equivalent of the consumption of 700 households, excluding heating,” the company wrote in a detailed report. For 2022, the expected agricultural yield is expected to increase to nine tons/hectare.

Read more at ‘PV Magazine‘

The QPV Group at UNSW in partnership with researchers at the National Renewable Energy Laboratory (NREL) in the USA have set a new world record of 32.9% marking the highest double-junction solar cell efficiency achieved to date under AM1.5G. One novel aspect is the bottom sub-cell is formed from an artifical semiconductor composed of a strain-balanced stack of GaAsP/InGaAs quantum wells yjay gives rise to properties not found in natural semiconductor alloys. Quantum wells have been used extensibvely in semiconductor lasers and LEDs but this is the first time that this type of artifiical semiconductor has resulted in a more efficient tandem solar cell.

Read more about this result:

• Research paper published in Advanced Energy Materials
• News item published by NREL Quantum Wells Enable Record-Efficiency Two-Junction Solar Cell
• Article in PV Magazine New approach to III-V tandems sets 32.9% efficiency record
• Article in Renew Economy Australian researchers help set new records for ultra-high efficiency solar cells
• Article in Green Review Quantum wells enable record-efficiency two-junction solar cell

Perovskite solar cells have seen a rapid rise in recent years due to their potential for low-cost processing and high power conversion efficiencies. Passivation of perovskite cells, especially at the perovskite-charge transport layer interfaces, plays a key role in reducing nonradiative recombination and to achieve high open-circuit voltages. Polymer passivation layers are typically used for this purpose; however, such layers are poor conductors, leading to a trade-off between passivation quality (voltage) and series resistance (fill factor).

A nanopatterned electron transport layer consisting of a sparse array of TiO₂ nanorods was developed that overcomes this trade-off by forming nanoscale localized charge transport pathways through a passivated interface, thereby providing both effective passivation and excellent charge extraction.

A certified power conversion efficiency of 21.6% was achieved for a 1-square-centimetre cell with a FF of 0.839. Encapsulated cells retained >91% of their initial efficiency after 1000 hours of damp heat exposure.

[1]. J. Peng, D. Walter, Y. Ren, M. Tebyetekerwa, Y. Wu, T. Duong, Q. Lin, J. Li, T. Lu, M. A. Mahmud, O. L. C. Lem, S. Zhao, W. Liu, Y. Liu, H. Shen, L. Li, F. Kremer, H. T. Nguyen, D.-Y. Choi, K. J. Weber, K. R. Catchpole and T. P. White, “Nanoscale localized contacts for high fill factors in polymer-passivated perovskite solar cells”, Science, 2021, 371, 390-395.

Nanoscale localized contacts for high fill factors in polymer-passivated perovskite solar cells – Report
New world record in perovskite solar cell efficiency

Australia achieved another impressive milestone in the transition to a low carbon future when South Australia was fully powered by Photovoltaics for 1 hour on Sunday, 11 October 2020. This is a unique achievement globally as South Australia has an area of close to 1 million km²  which is one and a half times bigger than Texas and five times the United Kingdom! The photovoltaic energy was mostly supplied by rooftop solar at 77%, whereas the remainder was provided by large-scale PV. The actual renewable energy production was well above 100%, and the remainder was either stored in batteries or exported to Victoria.

The long-term stability of solar cells under illumination is of key importance for their application. Generally, it assumed that solar cells using n-type silicon do not suffer from light-induced degradation due to the absence of significant amounts of boron in the bulk of the material, i.e., making these solar cells immune to the boron-oxygen defect. However, Madumelu and co-workers [1] recently reported that they observed a significant amount of degradation after light soaking. These measurements were done at temperatures of 160 ^oC to accelerate the testing.

As can be seen in the figure below, a significant reduction in solar cell efficiency up to 1 % absolute was found when the solar cells were illuminated, whereas an improvement was observed when the solar cells were kept in the dark. The authors related the change in solar cell performance to changes in the amorphous silicon heterojunction contact. It should be noted that amorphous silicon is stable at the temperatures used in this work and that similar illuminated anneals do not seem to affect other types of solar cells such as PERC.

Further work is needed to identify the exact nature of this defect and to investigate if this can also affect photovoltaic modules with silicon heterojunction cells in the field which would typically operate at significantly lower temperatures. 

Solar conversion efficiency of individual cells as a function of time after either dark-annealing (DA) or light-soaking at 1 kWm^-2 illumination intensity at a temperature of 160 ◦C. A reference cell that was stored at room temperature was included to test the repeatability of the measurement. All I-V measurements were conducted ex-situ under standard testing conditions.

[1]           C. Madumelu, B. Wright, A. Soeriyadi, M. Wright, D. Chen, B. Hoex, and B. Hallam, “Investigation of light-induced degradation in N-Type silicon heterojunction solar cells during illuminated annealing at elevated temperatures,” Solar Energy Materials and Solar Cells, vol. 218, p. 110752, 2020

The photovoltaic field is currently working hard to identify the ideal candidate for a silicon-based tandem solar cell. From a material perspective, an ideal top cell has a bandgap of ~1.6 eV, high absorption coefficient, and consists of only earth abundant and ecofriendly materials. In addition, it should also be easy to manufacture, compatible with silicon, and have a long-term stable performance.

Solar cells based on antimony sulphide/selenide have all these desired properties, however, their solar cell performance was still too low with record efficiencies around the 7% range. On 20 July 2020, a team of researchers from China and Australia have reported the first antinomy sulphide/selenide with an efficiency above 10% in the journal Nature Energy [1].

They achieved this landmark result by optimising the deposition and post-processing step of the absorber material resulting in a significant improvement in its morphology, grain size, and a reduction in the defect density in the film. This result illustrates the potential for this material as a candidate for future silicon-based tandem solar cells.

[1]  R. Tang, X. Wang, W. Lian, J. Huang, Q. Wei, M. Huang, Y. Yin, C. Jiang, S. Yang, G. Xing, S. Chen, C. Zhu, X. Hao, M. A. Green, and T. Chen, “Hydrothermal deposition of antimony selenosulfide thin films enables solar cells with 10% efficiency,” Nature Energy, 5, pages587–595(2020).