Researchers have created a new type of solar cell that replaces silicon with a crystal called perovskite. This design converts sunlight to electricity at efficiencies similar to current technology but at much lower cost.
A new design for solar cells that uses inexpensive, commonly available materials could rival and even outperform conventional cells made of silicon.
Writing in the Oct. 21 edition ofScience, researchers from Stanford and Oxford describe using tin and other abundant elements to create novel forms of perovskite – a photovoltaic crystalline material that’s thinner, more flexible and easier to manufacture than silicon crystals.
“Perovskite semiconductors have shown great promise for making high-efficiency solar cells at low cost,” said study co-author Michael McGehee, a professor of materials science and engineering at Stanford. “We have designed a robust, all-perovskite device that converts sunlight into electricity with an efficiency of 20.3 percent, a rate comparable to silicon solar cells on the market today.”
The new device consists of two perovskite solar cells stacked in tandem. Each cell is printed on glass, but the same technology could be used to print the cells on plastic, McGehee added.
“The all-perovskite tandem cells we have demonstrated clearly outline a roadmap for thin-film solar cells to deliver over 30 percent efficiency,” said co-author Henry Snaith, a professor of physics at Oxford. “This is just the beginning.”
Previous studies showed that adding a layer of perovskite can improve the efficiency of silicon solar cells. But a tandem device consisting of two all-perovskite cells would be cheaper and less energy-intensive to build, the authors said.
“A silicon solar panel begins by converting silica rock into silicon crystals through a process that involves temperatures above 3,000 degrees Fahrenheit (1,600 degrees Celsius),” said co-lead author Tomas Leijtens, a postdoctoral scholar at Stanford. “Perovskite cells can be processed in a laboratory from common materials like lead, tin and bromine, then printed on glass at room temperature.”
But building an all-perovskite tandem device has been a difficult challenge. The main problem is creating stable perovskite materials capable of capturing enough energy from the sun to produce a decent voltage.
A typical perovskite cell harvests photons from the visible part of the solar spectrum. Higher-energy photons can cause electrons in the perovskite crystal to jump across an “energy gap” and create an electric current.
A solar cell with a small energy gap can absorb most photons but produces a very low voltage. A cell with a larger energy gap generates a higher voltage, but lower-energy photons pass right through it.
An efficient tandem device would consist of two ideally matched cells, said co-lead author Giles Eperon, an Oxford postdoctoral scholar currently at the University of Washington.
“The cell with the larger energy gap would absorb higher-energy photons and generate an additional voltage,” Eperon said. “The cell with the smaller energy gap can harvest photons that aren’t collected by the first cell and still produce a voltage.”
The smaller gap has proven to be the bigger challenge for scientists. Working together, Eperon and Leijtens used a unique combination of tin, lead, cesium, iodine and organic materials to create an efficient cell with a small energy gap.
“We developed a novel perovskite that absorbs lower-energy infrared light and delivers a 14.8 percent conversion efficiency,” Eperon said. “We then combined it with a perovskite cell composed of similar materials but with a larger energy gap.”
The result: A tandem device consisting of two perovskite cells with a combined efficiency of 20.3 percent.
“There are thousands of possible compounds for perovskites,” Leijtens added, “but this one works very well, quite a bit better than anything before it.”
One concern with perovskites is stability. Rooftop solar panels made of silicon typically last 25 years or more. But some perovskites degrade quickly when exposed to moisture or light. In previous experiments, perovskites made with tin were found to be particularly unstable.
To assess stability, the research team subjected both experimental cells to temperatures of 212 degrees Fahrenheit (100 degrees Celsius) for four days.
“Crucially, we found that our cells exhibit excellent thermal and atmospheric stability, unprecedented for tin-based perovskites,” the authors wrote.
“The efficiency of our tandem device is already far in excess of the best tandem solar cells made with other low-cost semiconductors, such as organic small molecules and microcrystalline silicon,” McGehee said. “Those who see the potential realize that these results are amazing.”
The next step is to optimize the composition of the materials to absorb more light and generate an even higher current, Snaith said.
“The versatility of perovskites, the low cost of materials and manufacturing, now coupled with the potential to achieve very high efficiencies, will be transformative to the photovoltaic industry once manufacturability and acceptable stability are also proven,” he said.
The Latest on: Perovskite solar cell
via Google News
The Latest on: Perovskite solar cell
- Adding alkali metal to perovskite solar cells changes the solar game on February 18, 2019 at 10:46 pm
Researchers from Georgia Tech, UC San Diego and MIT havr discovered that adding alkali metal to perovskite solar cells could enable energy devices to last longer and maintain better performance. “Pero... […]
- Alkali metals improve efficiency of perovskite solar cells on February 18, 2019 at 8:04 pm
Perovskite-based solar cells are simple and cheap to produce, offer flexibility that could unlock a wide new range of installation methods and places, and in recent years have reached energy efficienc... […]
- Strain engineering in perovskite solar cells and its impacts on carrier dynamics on February 18, 2019 at 2:25 am
The mixed halide perovskites have emerged as outstanding light absorbers for efficient solar cells. Unfortunately, it reveals inhomogeneity in these polycrystalline films due to composition separation ... […]
- Nova Scotia start‑up a game changer for future of clean energy on February 15, 2019 at 6:40 am
Led by two long-time friends, Sam March and Dane George, Rayleigh Solar Tech is aiming commercialize perovskite solar cells. Perovskite is a solution deposited at low temperatures, easy to make, and w... […]
- Perovskite homojunction reduces charge carrier recombination on February 12, 2019 at 10:10 am
A cross-sectional SEM image of a homojunction PSC. Courtesy: Meicheng Li Perovskite solar cells (PSCs) made from organic-inorganic halides are a promising photovoltaic technology thanks to their remar... […]
- New Discovery Boosts Performance of Perovskite-based Solar Cells on February 12, 2019 at 9:06 am
Scientists from three leading US research institutes found a way to increase life-time of perovskite solar sells. It could finally make the technology viable when used in energy devices. A couple of y... […]
- Perovskite Solar Cells Module market explored in latest research on February 11, 2019 at 11:40 pm
News from QY Research, Inc. QY Research has published the new industry research report focuses on Global major leading players with information such as company profiles, product picture, future road m... […]
- Cesium and rubidium salt improve yield of perovskite cells on February 8, 2019 at 4:47 am
... at the University of California San Diego claim to have found a way to increase the efficiency of a perovskite-based solar cell by around 2% by simply adding small amounts of cesium or rubidium sa... […]
- Unleashing perovskites' potential for solar cells on February 7, 2019 at 1:22 pm
Solar cells made of perovskite have great promise, in part because they can easily be made on flexible substrates, like this experimental cell. Credit: Ken Richardson Perovskites—a broad ... […]
via Bing News