Skip to Content
Uncategorized

Promising New Solar Material Boosts Performance of Silicon

Researchers say they’ve overcome an obstacle to making highly efficient solar devices by combining silicon with a new material.
January 7, 2016

Silicon probably won’t be replaced as the dominant solar material anytime soon, but it might not be too long before it gets a partner from a promising class of materials called perovskites.

A group led by Henry Snaith, a physicist at the University of Oxford and leading perovskite researcher, has demonstrated what it says is a viable pathway to a device that combines a conventional silicon cell with a perovskite cell to boost the efficiency of that silicon cell by several percentage points.

Perovskites, which have captured the interest of solar researchers and energy policy experts because of their rapidly improving performance and low cost, are distinguished by a chemical structure that gives rise to unique electronic properties that make them attractive for solar technology (see “Could a New Solar Material Outperform Silicon?”). Snaith and his colleagues say the new composition they’ve developed overcomes a fundamental obstacle to designing a highly efficient device that combines the light-absorbing characteristics of silicon with those of a perovskite material.

The researchers say the result suggests it should be possible to make a silicon-perovskite “tandem” device that is more than 25 percent efficient, higher than the performance of today’s commercially available silicon cells, which are about 17 to 20 percent efficient. The measurements they took were in a laboratory environment, but the approach could eventually be used to achieve significantly higher efficiencies than the best silicon panels on the market today.

High-performance tandem devices made of semiconductors other than perovskite have already achieved efficiencies in the lab of over 40 percent, but they are extremely expensive because they require very technically complex manufacturing processes. Making perovskite solar cells is much simpler and cheaper, and the process could be integrated into existing silicon panel manufacturing lines by adding a few steps. Many experts believe the most realistic near-term commercial application of perovskites will be a tandem device with silicon.

Several groups have demonstrated working tandem devices made of a silicon cell and a perovskite cell, but the efficiencies have been limited because the range of the solar spectrum the perovskite absorbed did not fully complement the range that silicon absorbs. Attempts to tweak the range of light the perovskite absorbs led to instabilities within the material’s structure that compromised performance. Snaith and his colleagues came up with a method, which relies on substituting certain ions in the material with cesium ions, to achieve the desired photovoltaic properties while maintaining the material’s structural stability.

The researchers have only demonstrated the new composition at a small scale, and a lot of work would be needed before we might see it in commercially available panels. But a company Snaith cofounded, Oxford PV, is also focused on developing silicon-perovskite tandem devices. 

Chris Case, chief technology officer of Oxford PV, says results like this reflect how quickly researchers are addressing the inherent challenges to making reliable, high-performing tandem cells. Case won’t reveal the specifics of his company’s technology, but says Oxford PV is close to demonstrating full-size devices that are 23 percent efficient and could hit 25 percent shortly thereafter. Case says it’s not unrealistic to think 28 or even 30 percent efficiency is possible within just a few years.

Perovskite-based technologies still face challenges due to the material’s sensitivity to moisture and air, and questions remain about whether perovskite cells can be made durable enough to survive the long lifetimes required of power systems. Still, Case says Oxford PV is on track to deliver a commercial product—aimed at silicon panel manufacturers who want to “upgrade” the efficiency of their products—in 2017.

Keep Reading

Most Popular

10 Breakthrough Technologies 2024

Every year, we look for promising technologies poised to have a real impact on the world. Here are the advances that we think matter most right now.

Scientists are finding signals of long covid in blood. They could lead to new treatments.

Faults in a certain part of the immune system might be at the root of some long covid cases, new research suggests.

AI for everything: 10 Breakthrough Technologies 2024

Generative AI tools like ChatGPT reached mass adoption in record time, and reset the course of an entire industry.

OpenAI teases an amazing new generative video model called Sora

The firm is sharing Sora with a small group of safety testers but the rest of us will have to wait to learn more.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.