Scientists Boost Stability of Low-Cost, Large-Area Solar Modules
January 23, 2019 | OISTEstimated reading time: 3 minutes
Scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) have resolved a fundamental weakness in a promising solar technology known as Perovskite Solar Cells, or PSCs. Their innovations appear to improve both the devices’ stability and scalability in one fell swoop and could be key to moving PSCs to market.
Third-generation solar cells efficiently convert sunlight into usable electricity and cost less energy to manufacture than old-school silicon cells. PSCs, in particular, have garnered the attention of science and industry thanks to their low cost and high efficiency. Though their performance is promising in lab tests, the devices still suffer from low stability and cannot be produced commercially until they’re built to last.
“We need solar modules that can last for at least 5 to 10 years. For now, the lifetime of PSCs is much shorter,” said Dr. Longbin Qiu, first author of the paper and a postdoctoral scholar in the OIST Energy Materials and Surface Sciences Unit, led by Prof. Yabing Qi.
The study, published online in Advanced Functional Materials on December 13, 2018, supports prior evidence that a commonly used material in PSCs, called titanium dioxide, degrades the devices and limits their lifetime. The researchers replaced this material with tin dioxide, a stronger conductor without these degrading properties. They optimized their method of applying tin dioxide to produce stable, efficient and scalable PSCs.
In experiments, the researchers found that tin dioxide-based devices showed lifetimes over three times longer than PSC devices using titanium dioxide. “Tin dioxide can give users the device performance they need,” said Qiu.
An Improved Design
PSCs consist of layered materials, each with a specific function. The “active layer,” made from perovskite materials, absorbs incoming sunlight in the form of particles called photons. When a photon strikes a solar cell, it generates negatively-charged electrons and positively-charged holes in the active layer. Scientists control the flow of these electrons and holes by sandwiching the active layer between two “transport materials,” thus creating a built-in electrical field.
To help usher electrons in the right direction, many PSCs include an “electron transport layer.” Most PSCs employ titanium dioxide as their electron transport layer, but when exposed to sunlight, the material reacts with perovskite and ultimately degrades the device. Tin dioxide stands as a viable replacement for titanium dioxide, but before this study, it had not been successfully incorporated into a large-scale device.
Using a common technique in the industry called sputtering deposition, the researchers learned how to craft an effective electron transport layer from tin dioxide. Sputtering deposition works by bombarding the target material, here tin dioxide, with charged particles, causing it to spray upwards onto a waiting surface. By precisely controlling the power of the sputtering and speed of the deposition, the researchers produced smooth layers with a uniform thickness over a large area.
*Their new solar cells achieved an efficiency of over 20%. To demonstrate the scalability of this new method, the researchers then fabricated 5 by 5 centimeter solar modules with a designated area of 22.8 square-centimeters, finding that the resulting devices showed over 12% efficiency. This research, which was supported by the OIST Technology Development and Innovation Center’s Proof-of-Concept Program, represents a crucial step forward towards meeting the current industry standard for PSC efficiency.
Dr. Longbin Qiu holds up a sheet of solar cells made from flexible materials. The Energy Materials and Surface Sciences Unit aims to develop these devices to craft solar curtains and solar technologies that can be easily incorporated into people’s homes.
Moving to Market
The researchers plan to continue optimizing their PSC design with the goal of producing large-scale solar modules with improved efficiency. The research unit experiments with flexible, transparent solar devices and aims to apply their optimized PSC design in solar windows, curtains, backpacks and deployable charging units.
“We want to scale these devices up to a large size, and though their efficiency is already reasonable, we want to push it further,” said Prof. Qi. “We are optimistic that in the next few years, this technology will be viable for commercialization.”
Suggested Items
Groundbreaking Ceremony Marks the Beginning of a New Era for Newccess Industrial; The Construction of the MINGXIN Building
04/12/2024 | Newccess IndustrialOn a clear and sunny day in March, the groundbreaking ceremony for the MINGXIN Building took place in Shenzhen, China. This moment marked the official commencement of construction for a project that will reshape the semiconductor materials industry.
The Need for a Holistic Global Sustainability Standard
04/10/2024 | Michael Ford, Aegis SoftwareNo one can deny that the resources of our fragile planet are finite. The environment seems like a third party, subject to constant degradation. We’re acutely aware of the effects of pollution on our climate, and despite our “throw-away” culture, recycling and recovery of materials has remained relatively expensive, even as we use more energy just to survive.
iNEMI Publishes Four Roadmap Topics
04/04/2024 | iNEMIThe International Electronics Manufacturing Initiative (iNEMI) announces the availability of the first roadmap topics in the new iNEMI Roadmap format. Printed circuit boards, sustainable electronics, smart manufacturing, and mmWave materials and test are now available online.
Insulectro’s 'Storekeepers' Extend Their Welcome to Technology Village at IPC APEX EXPO
04/03/2024 | InsulectroInsulectro, the largest distributor of materials for use in the manufacture of PCBs and printed electronics, welcomes attendees to its TECHNOLOGY VILLAGE during this year’s IPC APEX EXPO at the Anaheim Convention Center, April 9-11, 2024.
Checking In With ICAPE Group
04/03/2024 | Nolan Johnson, I-Connect007ICAPE Group’s field application engineer Erik Pederson drills down on sustainability, supply chain resiliency, and what value engineering really looks like in this exclusive interview. Founded in 1999, European-based ICAPE Group provides 21 million printed circuit boards and over six million technical parts to manufacturers every month. With 30 PCB manufacturing partners globally and 50 partners providing a wide array of technical parts, ICAPE Group has operations in China, Taiwan, Thailand, South Korea, Vietnam, South Africa, Europe, Mexico, and the United States. The company also focuses on the value proposition for its customers.