Solar Energy

Use of perovskite will be a key feature of the next generation of electronic appliances

Published

4 years ago

March 15, 2021

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Use of perovskite will be a key feature of the next generation of electronic appliances

Quantum dots are manmade nanoparticles of semiconducting material comprising only a few thousand atoms. Because of the small number of atoms, a quantum dot’s properties lie between those of single atoms or molecules and bulk material with a huge number of atoms. By changing the nanoparticles’ size and shape, it is possible to fine-tune their electronic and optical properties – how electrons bond and move through the material, and how light is absorbed and emitted by it.

Thanks to increasingly refined control of the nanoparticles’ size and shape, the number of commercial applications has grown. Those already available include lasers, LEDs, and TVs with quantum dot technology.

However, there is a problem that can impair the efficiency of devices or appliances using this nanomaterial as an active medium. When light is absorbed by a material, the electrons are promoted to higher energy levels, and when they return to their fundamental state, each one can emit a photon back to the environment. In conventional quantum dots the electron’s return trip to its fundamental state can be disturbed by various quantum phenomena, delaying the emission of light to the exterior.

The imprisonment of electrons in this way, known as the “dark state”, retards the emission of light, in contrast with the path that lets them return quickly to the fundamental state and hence to emit light more efficiently and directly (“bright state”).

This delay can be shorter in a new class of nanomaterial made from perovskite, which is arousing considerable interest among researchers in materials science as a result (read more at: agencia.fapesp.br/32682/).

A study conducted by researchers in the Chemistry and Physics Institutes of the University of Campinas (UNICAMP) in the state of Sao Paulo, Brazil, in collaboration with scientists at the University of Michigan in the United States, made strides in this direction by providing novel insights into the fundamental physics of perovskite quantum dots.

“We used coherent spectroscopy, which enabled us to analyze separately the behavior of the electrons in each nanomaterial in an ensemble of tens of billions of nanomaterials. The study is groundbreaking insofar as it combines a relatively new class of nanomaterials – perovskite – with an entirely novel detection technique,” Lazaro Padilha Junior, principal investigator for the project on the Brazilian side, told Agencia FAPESP.

FAPESP supported the study via a Young Investigator Grant and a Regular Research Grant awarded to Padilha.

“We were able to verify the energy alignment between the bright state [associated with triplets] and the dark state [associated with singlets], indicating how this alignment depends on the size of the nanomaterial. We also made discoveries regarding the interactions between these states, opening up opportunities for the use of these systems in other fields of technology, such as quantum information,” Padilha said.

“”Owing to the crystal structure of perovskite, the level of bright energy divides into three, forming a triplet. This provides various paths for excitation and for the electrons to return to the fundamental state. The most striking result of the study was that by analyzing the lifetimes of each of the three bright states and the characteristics of the signal emitted by the sample we obtained evidence that the dark state is present but located at a higher energy level than two of the three bright states.

This means that when light is shone on the sample the excited electrons are trapped only if they occupy the highest bright level and are then shifted to the dark state. If they occupy the lower bright levels, they return to the fundamental state more efficiently.”

To study how electrons interact with light in these materials, the group used multidimensional coherent spectroscopy (MDCS), in which a burst of ultrashort laser pulses (each lasting about 80 femtoseconds, or 80 quadrillionths of a second) is beamed at a sample of perovskite chilled to minus 269 degrees Celsius.

“The pulses irradiate the sample at tightly controlled intervals. By modifying the intervals and detecting the light emitted by the sample as a function of the interval, we can analyze the electron-light interaction and its dynamics with high temporal precision, mapping the typical interaction times, the energy levels with which they couple, and the interactions with other particles,” Padilha said.

The MDCS technique can be used to analyze billions of nanoparticles at the same time and to distinguish between different families of nanoparticles present in the sample.

The experimental system was developed by a team led by Steven Cundiff, principal investigator for the study at the University of Michigan. Some of the measurements were made by Diogo Almeida, a former member of Cundiff’s team and now at UNICAMP’s ultrafast spectroscopy laboratory with a postdoctoral fellowship from FAPESP under Padilha’s supervision.

Quantum dots were synthesized by Luiz Gustavo Bonato, a PhD candidate at UNICAMP’s Chemistry Institute. “The care Bonato took in preparing the quantum dots and his protocol were fundamentally important, as evidenced by their quality and size, and by the properties of the nanometric material,” said Ana Flavia Nogueira, co-principal investigator for the study in Brazil. Nogueira is a professor at the Chemistry Institute (IQ-UNICAMP) and principal investigator for Research Division 1 at the Center for Innovation in New Energies (CINE), an Engineering Research Center (ERC) established by FAPESP and Shell.

“”The results obtained are very important since knowledge of the optical properties of the material and how its electrons behave opens up opportunities for the development of new technologies in semiconductor optics and electronics. The incorporation of perovskite is highly likely to be the most distinctive feature of the next generation of television sets,” Nogueira said.

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Solar Energy

China says wind and solar energy capacity exceeds thermal for first time

Published

8 hours ago

April 27, 2025

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China says wind and solar energy capacity exceeds thermal for first time

By Sam Davies and Luna Lin

Beijing (AFP) April 25, 2025

China’s wind and solar energy capacity has surpassed that of mostly coal-powered thermal for the first time, the national energy body said Friday.

China, the world’s largest emitter of greenhouse gases that drive climate change, has pledged to peak carbon emissions by 2030 and achieve carbon neutrality by 2060.

While around 60 percent of China’s energy comes from coal, the country is also a renewable energy powerhouse, building almost twice as much wind and solar capacity as every other country combined, according to research published last year.

“In the first quarter of 2025, China’s newly installed wind and photovoltaic power capacity totalled 74.33 million kilowatts, bringing the cumulative installed capacity to 1.482 billion kilowatts,” the national energy body said.

That surpassed the installed capacity of thermal power (1.451 billion kilowatts) for the first time.

President Xi Jinping said on Wednesday that “no matter how the international situation changes”, the country’s efforts to combat climate change “will not slow down”.

Xi also said China would announce its 2035 greenhouse gas reduction commitments, known as Nationally Determined Contributions (NDCs), before COP30 in November and that it would cover all greenhouse gases, not just carbon dioxide.

President Donald Trump meanwhile has pulled the United States, the world’s second-largest polluter, out of the Paris climate accord while pledging a vast expansion in fossil fuel exploitation.

-‘Structural change’-

China’s new milestone comes as the country experiences explosive growth in renewable energy.

Last year, China added a record 357 gigawatts of wind and solar, 10 times the US’s additions.

It met a 2030 target to install 1,200 GW of solar and wind capacity almost six years early.

Friday’s announcement said that wind and solar additions in the first quarter had “far exceeded” China’s total increase in electricity consumption.

“This trend is very likely to continue in the following months and quarters in 2025,” Yao Zhe, Global Policy adviser at Greenpeace East Asia, told AFP.

That suggests China’s power sector is undergoing “structural change and the sector’s carbon emissions are one small step away from peaking”.

However, coal continues to play a key role in China’s energy mix.

“The intermittency of variable renewables like wind and solar… means it’s generally inappropriate to compare them to firm, dispatchable power sources like coal,” according to David Fishman, senior manager at the Lantau Group.

“There is indeed some combination of wind plus solar plus storage that equals one coal plant, but the determination is different everywhere in the world.”

And China’s energy consumption continues to grow — by 4.3 percent last year.

Covering that growth with renewable power is a “tough proposition for a developing country with a huge heavy industrial segment and a residential population that frankly doesn’t even use that much electricity on a per capita basis”, Fishman said.

Despite the renewable energy boom, China also began construction on 94.5 gigawatts of coal power projects in 2024, 93 percent of the global total, according to a February report from the Finland-based Centre for Research on Energy and Clean Air (CREA) and Global Energy Monitor (GEM) in the United States.

China’s coal production has risen steadily in recent years, from 3.9 billion tons in 2020 to 4.8 billion tons in 2024.

That is despite Xi pledging to “strictly control” coal power before “phasing it down” between 2026 and 2030.

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Solar Energy

A single molecule elevates solar module output and stability

Published

3 days ago

April 24, 2025

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A single molecule elevates solar module output and stability

by Sophie Jenkins

London, UK (SPX) Apr 24, 2025

A new molecule developed through international collaboration has been shown to significantly improve both the performance and durability of perovskite solar cells, according to a recent study published in *Science*. The discovery centers on a synthetic ionic salt named CPMAC, which originates from buckminsterfullerene (C60) and has been shown to outperform traditional C60 in solar applications.

Researchers from the King Abdullah University of Science and Technology (KAUST) played a key role in the development of CPMAC. While C60 has long been used in perovskite solar cells due to its favorable electronic properties, it suffers from stability issues caused by weak van der Waals interactions at the interface with the perovskite layer. CPMAC was engineered to address these shortcomings.

“For over a decade, C60 has been an integral component in the development of perovskite solar cells. However, weak interactions at the perovskite/C60 interface lead to mechanical degradation that compromises long-term solar cell stability. To address this limitation, we designed a C60-derived ionic salt, CPMAC, to significantly enhance the stability of the perovskite solar cells,” explained Professor Osman Bakr, Executive Faculty of the KAUST Center of Excellence for Renewable Energy and Sustainable Technologies (CREST).

Unlike C60, CPMAC forms ionic bonds with the perovskite material, strengthening the electron transfer layer and thereby enhancing both structural stability and energy output. Cells incorporating CPMAC demonstrated a 0.6% improvement in power conversion efficiency (PCE) compared to those using C60.

Though the gain in efficiency appears modest, the impact scales up dramatically in real-world energy production. “When we deal with the scale of a typical power station, the additional electricity generated even from a fraction of a percentage point is quite significant,” said Hongwei Zhu, a research scientist at KAUST.

Beyond efficiency gains, CPMAC also enhanced device longevity. Under accelerated aging tests involving high heat and humidity over 2,000 hours, solar cells containing CPMAC retained a significantly higher portion of their efficiency. Specifically, their degradation was one third that observed in cells using conventional C60.

Further performance evaluation involved assembling the cells into four-cell modules, offering a closer approximation to commercial-scale solar panels. These tests reinforced the molecule’s advantage in both durability and output.

The key to CPMAC’s success lies in its capacity to reduce defects within the electron transfer layer, thanks to the formation of robust ionic bonds. This approach circumvents the limitations posed by van der Waals forces typical of unmodified C60 structures.

Research Report:C60-based ionic salt electron shuttle for high-performance inverted perovskite solar modules

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Solar Energy

Indonesia says China’s Huayou to replace LGES in EV battery project

Published

4 days ago

April 24, 2025

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Indonesia says China’s Huayou to replace LGES in EV battery project

by AFP Staff Writers

Jakarta (AFP) April 23, 2025

China’s Zhejiang Huayou Cobalt is replacing South Korea’s LG Energy Solution as a strategic investor in a multibillion-dollar project to build an electric vehicle battery joint venture in Indonesia, officials said on Wednesday.

The South Korean company, which was part of a consortium that signed a 142 trillion rupiah ($8.4 billion) “Grand Project” in 2020, announced its withdrawal from the project this week, citing factors including market conditions and the investment environment.

Energy and Mineral Resources Minister Bahlil Lahadalia said LG Energy Solution’s decision would not significantly affect the project, which aims to establish a local electric vehicle battery value chain in Indonesia.

“Changes only occur at the investor level, where LG no longer continue its involvement… and has been replaced by a strategic partner from China, namely Huayou,” Bahlil said in a statement.

“Nothing has changed from the initial goal, namely making Indonesia as the center of the world’s electric vehicle industry.”

Indonesia, home to the world’s largest nickel reserve, has been seeking to position itself as a key player in the global electric vehicle supply chain by leveraging its vast reserve of the critical mineral to attract investments.

The government decided not to move forward with the South Korean company in the project due to the long negotiation process with the firm to realise its investment, Investment Minister Rosan Roeslani said.

Rosan cited Huayou’s familiarity with Indonesia as one of the reasons why the government chose the company to succeed LG Energy Solution.

“Huayou had invested in Indonesia,” Rosan said.

“They have sources to develop the industry going forward.”

LG Energy Solution said in a statement on Tuesday that it will continue to explore “various avenues of collaboration” with the Indonesian government, including in its battery joint venture.

HLI Green Power, a joint venture between LG Energy Solution and Hyundai Motor Group, operates Indonesia’s first electric vehicle battery plant, which was launched in 2024 with a production capacity of up to 10 Gigawatt hours (GWh) of cells annually.

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