Solar Energy

A new modifier increases the efficiency of perovskite solar cells

Published

3 years ago

February 12, 2021

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A new modifier increases the efficiency of perovskite solar cells

The research team of NUST MISIS has presented an improved structure of perovskite solar cells. Scientists have modified perovskite-based solar cells using MXenes – thin two-dimensional titanium carbides with high electrical conductivity.

The MXenes-based modified cells showed superior performance, with power conversion efficiency exceeding 19% (the reference demonstrated 17%) and improved stabilized power output with respect to reference devices. The results have been published in the Nano energy international scientific journal.

Perovskite solar cells are promising alternative energy technology worldwide. They can be printed on special inkjet or slot die printers with minimal quantity of vacuum processes. This reduces the cost of the device compared to traditional silicon solar cell technology.

Their other advantages are flexibility (the solar cell can be made on substrates of PET a common material for plastic bottles) and compactness. Perovskite solar cells can be mounted on the walls of buildings and curved surfaces of automobile panoramic roofs, receiving independent power supply.

The perovskite module has a sandwich structure: there is a process of collecting electrons between the layers. As a result, the energy of sunlight is converted into electrical energy.

The layers are very thin – from 10 to 50 nanometers, and the “sandwich” itself is thinner than a human hair. The collection of the charge carriers in the solar cells should go with minimal losses during electron transport. The reduction of the such losses in the device will increase the power of the solar cell.

A scientific group of physicists from NUST MISIS and the University of Tor Vergata (Rome, Italy) have shown experimentally that the addition of a small amount of titanium carbide-based MXenes to light-absorbing perovskite layers improves the electronic transport process and optimizes the performance of the solar cell.

The name – MXenes comes from the synthesis process. The material is made by etching and exfoliation of the atomically thin metal carbides pre-coated with aluminum (MAX phases – layered hexagonal carbides and nitrides).

“”In this work, we demonstrate a useful role of MXenes doping both for the photoactive layer (perovskite) and for the electron transport layer (fullerenes) in the structure of solar cells based on nickel oxide,” said the co-author of the paper, a researcher from the NUST MISIS Laboratory for Advanced Solar Energy, post-graduate student Anastasia Yakusheva.

“On the one hand, the addition of MXenes helps to align the energy levels at the perovskite/fullerene interface, and, on the other hand, it helps to control the concentration of defects in the thin-film device, and improves the collection of photocurrent.”

The solar cells developed with the new approach have shown improved characteristics with a power conversion efficiency exceeding 19%. This is 2% more in comparison to the reference devices.

The approach proposed by the developers can be easily scaled to the format of modules and large-area panels. Doping with MXenes does not change the fabrication sequence and integrated only to the initial stage of ink preparation without changes to architecture of the device.

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Solar Energy

Project receives funding for advanced solar-thermal research

Published

5 days ago

April 12, 2024

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Project receives funding for advanced solar-thermal research

by Sophie Jenkins

London, UK (SPX) Apr 12, 2024

The University of Surrey, leading a collaboration with the University of Bristol and Northumbria University, has received a GBP 1.1 million grant from the Engineering and Physical Sciences Research Council (EPSRC) to develop solar-thermal devices. These devices aim to revolutionize the way we heat homes and generate power, differing from traditional solar cells by converting sunlight into heat for energy production.

The research focuses on creating surfaces that selectively absorb sunlight and emit heat through near-infrared radiation. This project leverages the combined expertise of the institutions in photonics, advanced materials, applied electromagnetics, and nanofabrication to address a global need for efficient solar energy utilization.

Professor Marian Florescu, Principal Investigator from Surrey, highlighted the importance of the project: “The sun provides an immense amount of energy daily, much more than we currently harness. By advancing these solar-absorbing surfaces, we aim to transform solar energy use into a sustainable powerhouse for our increasing energy needs.”

Goals of the project include developing high-temperature solar absorbers, enhancing the efficiency of solar-absorbing structures, and improving the management of heat generated from sunlight. Prototypes will be constructed to demonstrate these technologies.

Professor Marin Cryan, Co-Principal Investigator from the University of Bristol, explained their focus on thermionic solar cell technology, which uses concentrated sunlight to initiate electron emission for high-efficiency solar cells.

Dr. Daniel Ho, Co-Principal Investigator from Northumbria University, added: “Our university leads in thermophotovoltaic research, utilizing advanced thermal analysis techniques. We’re excited to contribute to groundbreaking developments in renewable energy.”

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Solar Energy

Improving Solar and Wind Power Integration in the U.S. Grid

Published

6 days ago

April 11, 2024

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Improving Solar and Wind Power Integration in the U.S. Grid

by Clarence Oxford

Los Angeles CA (SPX) Apr 11, 2024

The Midcontinent Independent System Operator manages a high-voltage electricity network spanning from Manitoba to Louisiana, serving 45 million users. This vast operation requires maintaining a balance between the energy generated and the demand across its regions.

The traditional reliance on coal and natural gas power plants is changing. For example, wind farms in Iowa now generate over 64% of the state’s electricity, and recent initiatives like the Alliant Energy Solar Farm at Iowa State University represent the shift towards renewable energy sources. These sources, however, introduce variability and uncertainty into grid management.

Zhaoyu Wang, a Northrop Grumman associate professor of electrical and computer engineering at Iowa State, emphasized, The power system seeks certainty which is challenging with unpredictable natural resources like sun and wind.

Wang is leading the MODERNISE project, aimed at modernizing grid operations. The U.S. Department of Energy has earmarked a $3 million grant over three years for this initiative, with an additional $1.1 million coming from project collaborators including Argonne National Laboratory and Siemens Corp.

The project, titled Modernizing Operation and Decision-Making Tools Enabling Resource Management in Stochastic Environment, involves developing computational tools that allow for better integration and management of renewable energy sources into the grid.

Jennifer M. Granholm, U.S. Secretary of Energy, supported this initiative stating that effective integration of renewable resources is essential for deploying clean energy. The project is part of a larger $34 million investment by the DOE to develop technologies that enhance grid reliability and efficiency.

By aggregating smaller renewable energy resources into larger operational blocks, MODERNISE aims to improve grid stability and predictability. Bai Cui, project co-leader and assistant professor at Iowa State, explained that this approach allows operators to manage grid operations more effectively by understanding and handling the uncertainties of renewable supply sources.

This initiative promises to make grid operations more adaptable and efficient, critical for accommodating the increasing reliance on renewable energy.

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Solar Energy

Quantum Material Achieves Up to 190% Efficiency in Solar Cells

Published

6 days ago

April 11, 2024

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Quantum Material Achieves Up to 190% Efficiency in Solar Cells

by Clarence Oxford

Los Angeles CA (SPX) Apr 11, 2024

Researchers from Lehigh University have developed a material that significantly enhances the efficiency of solar panels.

A prototype incorporating this material as the active layer in a solar cell displays an average photovoltaic absorption rate of 80%, a high rate of photoexcited carrier generation, and an external quantum efficiency (EQE) reaching up to 190%. This figure surpasses the theoretical Shockley-Queisser efficiency limit for silicon-based materials, advancing the field of quantum materials for photovoltaics.

This work signifies a major advance in sustainable energy solutions, according to Chinedu Ekuma, professor of physics at Lehigh. He and Lehigh doctoral student Srihari Kastuar recently published their findings in the journal Science Advances. Ekuma highlighted the innovative approaches that could soon redefine solar energy efficiency and accessibility.

The material’s significant efficiency improvement is largely due to its unique intermediate band states, which are energy levels within the material’s electronic structure that are ideally positioned for solar energy conversion.

These states have energy levels in the optimal subband gaps-energy ranges capable of efficiently absorbing sunlight and producing charge carriers-between 0.78 and 1.26 electron volts.

Moreover, the material excels in absorbing high levels in the infrared and visible regions of the electromagnetic spectrum.

In traditional solar cells, the maximum EQE is 100%, which corresponds to the generation and collection of one electron for each photon absorbed. However, newer materials and configurations can generate and collect more than one electron per high-energy photon, achieving an EQE over 100%.

Multiple Exciton Generation (MEG) materials, though not yet widely commercialized, show immense potential for enhancing solar power system efficiency. The Lehigh-developed material utilizes intermediate band states to capture photon energy typically lost in traditional cells, including energy lost through reflection and heat production.

The research team created this novel material using van der Waals gaps, atomically small spaces between layered two-dimensional materials, to confine molecules or ions. Specifically, they inserted zerovalent copper atoms between layers of germanium selenide (GeSe) and tin sulfide (SnS).

Ekuma developed the prototype based on extensive computer modeling that indicated the system’s theoretical potential. Its rapid response and enhanced efficiency strongly indicate the potential of Cu-intercalated GeSe/SnS as a quantum material for advanced photovoltaic applications, offering a path for efficiency improvements in solar energy conversion, he stated.

While the integration of this quantum material into existing solar energy systems requires further research, the techniques used to create these materials are already highly advanced, with scientists mastering precise methods for inserting atoms, ions, and molecules.

Research Report:Chemically Tuned Intermediate Band States in Atomically Thin CuxGeSe/SnS Quantum Material for Photovoltaic Applications