Future of renewable energy with tandem solar technology

Revolutionizing Solar Energy: The Rise of Tandem Solar Cells for Higher Efficiency and Sustainability

Introduction

Solar panels on rooftops and expansive energy farms have become a familiar sight across many parts of the globe. Even in the cloudy UK, solar power is emerging as a key contributor to electricity generation.

The Solar Energy Boom

The Solar energy boom is primarily driven by two breakthroughs:

• First, advancements in mass production techniques enable the manufacturing of billions of solar panels, with each process step refined for maximum cost efficiency.
• The Second, and more critical, driver is the steady improvement in power conversion efficiency, which boosts the panels' ability to convert sunlight into electrical energy.

Increasing Efficiency and Reducing Costs

As solar panel efficiency improves, the cost of electricity decreases. This raises the question: how much more efficient can solar technology become, and will it significantly reduce our energy bills?

Present-day commercial solar panels typically convert 20-22% of sunligh into electricity. However, a study in Nature reveals that tandem solar cells could push this efficiency to 34%, marking a breakthrough in solar technology.

What exactly are Tandem Solar Cells?

Solar cells traditionally employ a single material to absorb sunlight, and most modern panels are crafted from silicon, also used in microchips. However, silicon's efficiency is restricted to about 29%.

Researchers have addressed this limitation by employing tandem solar cells, which layer two materials to capture a wider range of solar energy.

In a recent study published in Nature, researchers from the energy leader LONGi have introduced a new tandem solar cell that integrates silicon and perovskite materials. This innovation combination has resulted in a world record efficiency of 33.89% due to enhanced sunlight absorption.

Discovered less than twenty years ago, perovskite solar materials have proven to be an excellent complement to traditional silicon technology. Their unique light absorption tenability allows them to capture high-energy blue light more efficiently than silicon.

Enhancing Overall Efficiency

By implementing this approach, energy losses are minimized, leading to an increase in overall tandem efficiency. Other materials, known as III-V semiconductors, have been incorporated into tandem cells to achieve even higher efficiencies; however, their production is challenging and costly, which restricts their use to small solar cells combined with focused light.

The Role of the Scientific Community

The scientific community is dedicated to advancing perovskite solar cells, with efficiencies for lab single cells rising from 14% to 26% in a mere decade. This progress has enabled their integration into ultra-high-efficiency tandem soalr cells, illustrating a route to scale photovoltaic technology to meet the trillions of watts required to decarbonize global energy production.

The pricing of solar-generated electricity

These innovative tandem cells, which have achieved a new efficiency record, can absorb an extra 60% of solar energy. As a result, fewer panels are necessary to generate equivalent energy output, leading to reduced installation expenses and less land or rooftop area needed for solar installations.

This advancement also allows power plant operators to produce solar energy with greater profitability. Nevertheless, due to the current structure of electricity pricing in the UK, consumers may not perceive any changes in their electricity bills. The true impact is evident when examining rooftop soalr installations, where space is limited and must be utilized efficiently.

Factors Influencing Rooftop Solar Power Costs

The cost of rooftop solar power is determined by two primary factors: the total expense of installing solar panels on your roof and the anticipated electricity generation over their 25-year lifespan. While the installation costs are straightforward to assess, calculating the financial returns from generating solar electricity at home is more complex. Savings can be achieved by reducing reliance on grid energy during peak pricing periods, and homeowners can also sell excess electricity back to the grid.

However, the remuneration provided by grid operators for this electricity is quite low, so it may be more beneficial to invest in a battery to store energy for use during nighttime. Considering average metrics for a typical British household, I have estimated the cash savings consumers could realize from rooftop solar electricity based on the panels' efficiency.

Maximizing Savings Through Efficiency Improvements

By improving panel efficiency from 22% to 34% without raising installation costs, annual savings on electricity bills could escalate from £558 to £709. This 20% rise in cash savings would significantly boost the attractiveness of solar rooftop, even in the often gray and cloudy skies of Britain.

When will these New Solar Panels be available for Purchase?

Ongoing research is focused on enhancing this technology and confirming its long-term durability. The record-breaking tandem cells, currently produced in laboratories, are smaller than a postage stamp. Adapting this high performance to larger, meter-square areas presents a significant challenge.

However, progress is being made. Earlier this month, Oxford PV, a leader in perovskite technology, announced the initial sale of its newly developed tandem solar panels. They have effectively addressed the challenges of combining two solar materials to create durable and reliable panels. While their efficiency has not yet reached the 34% mark, their work indicates a promising pathway for next-generation solar cells.

Sustainability Considerations

Another important factor to consider is the sustainability of the materials utilized in tandem solar panels. The extraction and processing of certain minerals for solar panels can be extremely energy-intensive. In addition to silicon, perovskite solar cells require lead, carbon, iodine, and bromine to function effectively. The integration of perovskite and silicon also necessitates rare materials containing indium, indicating that further research is essential to overcome these challenges.

Commitment to Advancing Solar Technologies

Despite the obstacles, both the scientific and industrial sectors are dedicated to advancing tandem solar technologies that can be integrated into a wide array of applications, including vehicles, structures, and aircraft.

Conclusion

The latest advancements in high-efficiency perovskite-silicon tandem cells signal a promising future for solar energy, solidifying its role in the global shift towards renewable energy sources.

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Solar-powered fresh water production from seawater

Solar-Powered, Energy-Efficient Device Converts Seawater into Fresh Water

Introduction

Researchers from the University of Waterloo have engineered an energy-efficient system that produces fresh drinking water from seawater through a solar-driven evaporation process.

The Urgency of Desalination

Global Water Scarcity

As water scarcity intensifies due to expanding populations and increasing water consumption worldwide, desalination is crucial for coastal and island nations to maintain fresh water access.

UN World Water Development Report 2024

The UN World Development Report 2024 highlights that around 2.2 billion individuals worldwide are without access to clean water, reinforcing urgency for technological advancements in fresh water production.

Conventional Desalination Challenges

Energy-Intensive Methods

The conventional approach to desalination involves passing seawater through membranes to extract salt. However, this energy-intensive method often causes salt to accumulate on the membrane surfaces, hindering water flow and reducing system efficiency, which necessitates regular maintenance and prevents uninterrupted operation.

Innovative Solution from Waterloo Researchers

Nature-Inspired Technology

Waterloo researchers have created a device inspired by the natural water cycle, specifically how trees move water from their roots to their leaves. This novel technology provides a continuous desalination process with reduced maintenance requirements. The study is featured in Nature Communications.

Design and Functionality

Dr. Michael Tam, a professor in the Department of Chemical Engineering at Waterloo, explained, "We drew inspiration form nature's self-sustaining processes and the natural evaporation and condensation of water in the environment."

"The engineered system we created enables water to evaporate, move to the surface, and then condenses within a closed-loop system, which prevents salt from accumulating and reducing device efficiency."

Device Efficiency and Performance

Solar Power Efficiency

The device operates on solar power, converting approximately 93% of sunlight into energy--five times more efficient than existing desalination systems. It generates around 20 liters of fresh water per square meter, meeting the World Health Organization's daily recommended intake for drinking and hygiene.

Materials and Consturction

In their research, Ph.D. students Eva Wang and Weinan Zhao, among others, crafted the device using nickel foam that was coated with a conductive polymer and integrated with thermoresponsive pollen particles.

Sunlight is absorbed across the solar spectrum by this material, which then converts it into heat. A thin saltwater layer on the polymer is heated and moves upward, replicating the natural process of water movement in tree capillaries.

Maintenance and Operation

As the water evaporates, the residual salt accumulates in the device's bottom layer, similar to a backwash system in a swimming pool, thereby preventing blockages and ensuring uninterrupted operation.

Dr. Yuning Li, a professor in the Department of Chemical Engineering at Waterloo, assisted the research team by using a solar tester to evaluate the device's light-harvesting capabilities and generate solar energy for the project.

As Li explained, "This device is both efficient and portable, which makes it especially valuable in remote areas where fresh water is scarce. It offers a sustainable resolution to the developing water crisis."

Future Plans and Impact

Prototype Development

The Waterloo research team aims to construct a prototype of their device for maritime deployment, allowing for large-scale testing of the technology in future phases.

Potential Benefits

According to Tam, "If the testing is successful, the technology could sustainable deliver fresh water to coastal regions and support the UN's Sustainable Development Goals 3, 6, 10 and 12."

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Perovskite solar cell defect management

Passivation of Defects in Perovskite-Based Solar Cells

Introduction to Solar Energy and Perovskite Solar Cells

The Promise of Solar Energy

Solar energy presents a  promising solution for reducing reliance on Fossil Fuels, offering a cleaner alternative. Over time, solar cell technology has advanced significantly in harnessing this renewable resource.

Metal-Halide Perovskites as Light-Absorbing Materials

Metal-Halide perovskites have attracted considerable interest as effective light-absorbing materials for solar cells, thanks to their outstanding optoelectronic properties that facilitate efficient energy generation from sunlight.

Challenges in Polycrystalline Perovskite Solar Cells

The Role of Polycrystalline Formamidinium Lead Iodide (FAPbl₃)

Poly-crystalline formamidinium lead iodide (FAPbl₃) is a favored material for constructing high-power conversion efficiency (PCE) perovskite solar cells (PSCs) due to its narrow energy band gap. However, despite its excellent optoelectronic properties and versatility, polycrystalline perovskites like FAPbl₃ often exhibit crystal structure defects that impair structural stability and carrier dynamics, ultimately reducing energy conversion efficiency.

Innovative Defect Passivation Strategy by GIST Researchers

Development of a Novel Defect Passivation Strategy

Filling this gap, a team of researchers headed by Professor Hobeom Kim at GIST has devised a novel defect pasivation strategy, which effectively reduces defects and boosts both power conversion efficiency and stability in perovskite solar cells.

In their recent Nature Commuinications study, dated July 4, 2024, the team introduced hexagonal polytype (6H) perovskite into cubic FAPbl₃ (3C),leading to a remarkable rise in PCE compared to existing counterparts.

The Advantages of 6H Perovskite Polytype

Why Choose 6H Perovskite?

Why opt for the 6H perovskite polytype? Prof. Kim explains, "The conventional method has been to introduce external chemical reagents to address defect issues. However, these reagents can negatively affect the crystalline integrity of perovskites during growth. Our approach avoids such stabilizers, instead utilizing the 6H polytype--a chemically identical version of perovskite with a corner-sharing structure that effectively prevents defect formation."

Incorporation and Impact of 6H Perovskite

By introducing excess lead iodide and methylammonium chloride, the researchers incorporated 6H perovskite into FAPbl₃, thereby addressing the key defect site, Halide Vacancies (VI+), present in the α-phase cubic polytype (3C) FAPbl₃.

Results and Implications

Future Prospects and Applications

The introduction of the 6H phase was found to bolster the structural stability and carrier dynamics of FAPbl₃, yielding an impressive carrier lifetime exceeding 18 microseconds. This improvement enabled PSCs to reach a PCE of 24.13%, with a module achieving a PCE of 21.92% (Certified at 21.44%) and demonstrating long-term operational durability.

According to the researchers, the 3C/6H Hetero-Polytypic perovskite design may closely approach the ideal structure for polycrystalline perovskite films. The study showcased how manipulating defects in perovskites can accelerate the development of cutting-edge solar cells for diverse uses such as rooftop installations, wearable electronics, and portable charging solutions.

Conclusion

The Transformative Potential of Perovskite Solar Cells

According to Prof. Kim, perovskite solar cells offer a trans-formative approach to reaching carbon neutrality and mitigating global warming. Their efficiency, adaptability, and reduced environmental impact make them integral to the transition towards sustainability.

Innovative solar technologies reducing

Oxford University Physicists Pioneer Innovative Solar Technology

Breakthrough in Solar Energy Efficiency

• Oxford University physicists have pioneered an innovative method for producing solar electricity, eliminating the reliance on silicon-based panels by applying a novel energy-generating material to common surfaces like rucksacks, vehicles, and smartphones.

• The breakthrough light-absorbing material, now thin and flexible, can be applied to the surfaces of nearly any structure or common object. Utilizing an innovative stacking method developed in Oxford, which integrates multiple light-absorbing layers into a single solar cell, they have effectively broadened the spectrum of captured light, significantly increasing energy output.

Certification and Efficiency Achievements

• This ultra-thin material, utilizing the multi-junction approach, has achieved an independently certified energy efficiency exceeding 27% equaling the performance of conventional silicon photovoltaics for the first time. The certification was awarded by Japan's National Institute of Advanced Industrial Science and Technology (AIST) ahead of the research study's publication later this year.

• "In just five years of experimenting with our mulit-juction stacking approach, we have increased power conversion efficiency from approximately 6% to over 27%, approaching the theoretical limits of single-layer photovoltaics," stated Dr. Shuaifeng Hu, Postdoctoral Fellow at Oxford University Physics.

• "We are confident that, in the long term , this method has the potential to enable photovoltaic devies to exceed 45% efficiency."

Versatility and Commercial Potential

• In comparison, current solar panels achieve about 22% energy efficiency, converting roughly 22% of sunlight into usable energy. However, the true advantage of the new ultra-thin, flexible material lies in its versatility. Measuring just over one micron in thickness--nearly 150 times thinner than a silicon wafer---it can be applied to virtually any surface, unlike traditional photovoltaics, which are typically limited to silicon panels.

• "by utilizing novel materials that can be applied as a coating, we've demonstrated the ability to match and even exceed silicon's performance while adding flexibility. This is crucial, as it suggests the potential for generating more solar power without relying on extensive silicon panels or dedicated solar farms," stated Dr. Junke Wang, Marie Sklodowska Curie Actions Postdoctoral Fellow at Oxford University Physics.

• The researchers are confident that their approach will keep lowering the cost of solar energy, making it the most sustainable form of renewable power. Since 2010, the global average cost of solar electricity has decreased by almost 90%, rendering it nearly a third less expensive than fossil fuel-derived energy. Ongoing innovations are likely to yield furhter cost efficiencies as new materials like thin-film perovskite reduce the necessity for silicon panels and specialized solar farms.

• "We anticipate that perovskite coatings could be used on a wider range of surfaces to produce affordable solar power, including car roofs, buildings facades, and even mobile phone backs. If this method proves effective in generating more solar energy, it could significanlty reduce the future reliance on silicon panels and the need for additional solar farms," Dr. Wang explained.

• Among the 40 researchers working on photovoltaics under the guidance of Professor Henry Snaith at Oxford University's Physics Department, this team has been pioneering the field. Their innovative research on thin-film perovskite, initiated nearly ten years ago, is conducted using a custom-built robotic laboratory.

• Their innovative work demonstrates considerable commercial potential and is beginning to influence applications across the utilities, construction, and automotive sectors.

• Oxford PV, a UK-based company established in 2010 by Professor Henry Snaith, co-founder and Chief Scientific Officer, to commercialize perovskite photovoltaics, has recently commenced large-scale production of these cells at its Brandenburg-an-der-Havel facility near Berlin. This marks the world's inaugural volume manufacturing line for 'perovskite-on-silicon' tandem solar cells.

• Professor Snaith explained, "Initially, we considered UK locations for our manufacturing operations, but the government has not yet provided the fiscal and commercial incentives available in other European and US regions."

• "To date, the UK has primarily focused on expending solar energy through new solar farms. However, significant growth is expected to stem from commercializing innovative technologies. We hope that the newly established British Energy will prioritize this approach."

• Professor Snaith noted. "The provision of these materials is poised to become a rapidly expending sector within the global green economy. The UK has demonstrated scientific leadership and innovation, but without new incentives and improved pathways for translating this innovation into manufacturing, the UK risks missing the chance to spearhead this emerging global industry."

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