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Sustainability project factors happiness and making a buck

ASU sustainability students guide small organizations toward zero waste.
Other student-created finalists: PCs for Refugees and Solar Water Solutions.
February 20, 2017

Student team wins Pakis entrepreneurship prize with solution to eliminate waste, save money

No one wants to live in a world overflowing with garbage, but how does a regular person tackle such a complicated problem?

Three Arizona State University sustainability students have come up with a way to guide small organizations painlessly toward zero waste.

And they’ll make money doing it.

Their consulting firm, Circle Blue, will partner with schools, nonprofits and small businesses to find and eliminate waste, saving money and reducing the amount of garbage that goes to the landfills.

“Part of being sustainable is being happy, and in order to be happy we have to make money,” said Eric Johnson (pictured above), one of the Circle Blue team members.

“But that doesn’t mean we do it at the expense of society and the environment. We’re trying to create a new transformative business model to show that you can make money and be sustainable at the same time.”

The Circle Blue team won a $20,000 grant last week from the Pakis Social Entrepreneurship Challenge, defeating two other teams in the pitch competition. The event, sponsored by the Center for Entrepreneurship in the W. P. Carey School of Business at ASU, sought the team with the strongest potential to solve a social challenge.

Success in social entrepreneurship requires a firm grasp of complex problems and the ability to make enough money to be viable.

“Who wants to live in this world?” asked Johnson, showing a photo of overflowing garbage during the pitch event. “In the city of Tempe annually, we sent 1 million tons of waste to the landfill.

“That’s enough to fill Chase Field 14 times from bottom to top.”

Johnson said the firm is harnessing peoples’ desire to do the right thing and empowering them to find a way to do it.

“It’s not easy, but we provide them with the support they need to achieve zero waste,” he said.

The other two finalists were PCs for Refugees, which refurbishes donated computers and gives them to refugee families, and Solar Water Solutions, which retrofits water pumps in rural communities in Zimbabwe with solar-powered technology.

Fred PakisFred Pakis is managing director of Clarendon Capital Management and chairman of the Pakis Family Foundation. The Pakis Center for Business Philanthropy is part of the Arizona Community Foundation. Photo by Jordan Johnson/W. P. Carey School of Business, benefactor of the Pakis Center for Business Philanthropy, which funds the competition, said all three teams were strong.

“You’re all doing wonderful things for the world, which is the reason we put this contest together.”

Each team was awarded places in the “boot camp” run by Seed Spot, a Phoenix-based entrepreneurship incubator.

This is the second year of the Pakis Challenge. Last year’s winner was All Walks, a nonprofit group that created a program to teach life skills to survivors of sex trafficking. One of the last year’s finalist teams, 33 Buckets, is a nonprofit group that installs water-filtration devices in developing countries, and was featured in an ASU commercial during the Super Bowl.

Here’s more on this year’s teams, which each earned $7,500 for being named finalists:

Circle Blue

The team: Eric Johnson, Sean Murray and Daniel Velez are all master’s students in the School of Sustainability. The venture had its beginnings as Johnson’s thesis project when he was an undergraduate in Barrett, the Honors College.

The mission: Circle Blue is a consulting firm that partners with small to mid-size organizations to divert as much waste from landfills as possible. The company already has worked with Native American Connections on its multifamily housing units, saving it $13,000 on trash fees, and with two schools in the Tempe Elementary School District as pilot projects. Tempe Academy achieved 88 percent waste diversion after working with Circle Blue.

The model: A for-profit consulting firm, the company charges a fee for its services, which begins with a waste audit to see how much is being produced.

“From the outside it looks like we’re dumpster diving, but the reality is that we’re collecting a lot of valuable data,” said Velez.

The team then meets with the people in an organization to see what the obstacles are and to get everyone engaged before adapting new behaviors. At Tempe Academy, that meant a pep rally to fire up the students.

“First we focus on reducing. Are there ways we can minimize the amount of consumption to minimize trash?” Johnson said. “Second we focus on reusing materials. At Tempe Academy, we’ve been able to donate at least 50 pounds of food a day to the homeless. Previously it was going to a landfill.”

At some organizations, especially schools, up to 75 percent of waste is food, so composting is an important element.

“If you’re able to take that and create compost, that compost gets repurposed to grow new food,” Johnson said.

Why they do it: The team has done a lot of research on attitudes about sustainability and realized that while most people embrace it as a concept, they don’t know how to do it.

“We want to help people find the solutions they need. There’s a big disconnect between belief and action, and we’re trying to fill that gap,” Murray said.

What’s next: Circle Blue will use the $20,000 to expand its services to all schools in the Tempe district and to ramp up the business.

Riad Sbai, co-founder of PCs for Refugees, sets up a computer for a Syrian family. The organization takes donated laptops and personal computers, refurbishes them and gives them to refugees.

PCs for Refugees

The team: Riad Sbai, who has a master’s degree in health care delivery from ASU and now works as a web developer for a health care company; Louis Ship, a computer systems engineering major; Abdul Bayazid, a health sciences major; and Sudip Thomas, an employee at Intel. Sbai and Bayazid are Syrian Americans, and Sbai has lost family members to the war in Syria.

“The most difficult part of it all was the feeling of helplessness,” Sbai said. “The refugee community is a vulnerable population, and it’s more important than ever to show we do support them and want them to succeed.”

About 10 months ago, he and Bayazid began visiting newly arrived refugees and noticed that none of them had computers.

The mission: PCs for Refugees collects donated personal computers and laptops, refurbishes them and distributes them to Syrian refugee families who have settled in metro Phoenix. Then they work with Cox Communications, which has a program that provides internet service to low-income families with kids for $9.95 a month with no installation, modem or cancellation fees. The team members also provide computer training for each family. So far the team has donated to 97 families, with six refugees acquiring jobs because they had access to a computer.

The model: The team recently made PCs for Refugees a 501c3 nonprofit organization, so donations are tax-deductible.

Why they do it: “Lack of a computer is a big limitation. Everyone relies on a computer for doing homework, job searches, applications for scholarships and accessing resources,” Sbai said.

The biggest challenge for the families is learning English, and the PCs come with English-tutoring software, as well as educational and professional programs.

The first family that received a computer included a daughter who is disabled.

“This computer was really her lifeline to the world,” Sbai said.

The $7,500 finalist grant was a big help, because it costs $15 to $18 to refurbish each computer, usually for batteries, adapters, speakers, mice, monitors and other peripherals. Thomas took on the job of driving all over the Valley to pick up donations and deliver them to Sbai.

What’s next: The team hopes to expand to refugees from other countries besides Syria and to offer other computer skills, and will start a PCs for Refugees Club at ASU.

Ngoni Mugwisi, co-founder of Solar Water Solutions, describes the project during the Pakis Social Entrepreneurship Challenge. Photo by Jordan Johnson/W. P. Carey School of Business

Solar Water Solutions

The team: Ngoni Mugwisi and Mohammed Munir, both electrical engineering majors; Allistar Machacek, a construction management major.

The project began in EPICS, the Engineering Projects in Community Service course in which teams design, build and deploy systems to solve engineering-based problems for charities, schools and other not-for-profit organizations.

“It started as a sustainable gardens project, but the biggest way to improve is to learn from your mistakes and we learned that the project didn’t work quite as well as we thought it would,” Munir said. “So we shifted to water.”

The mission: Solar Water Solutions will retrofit existing water pumps with solar-powered submersible pumps in rural communities in sub-Saharan Africa. The team installed one pump in 2015 that supplies 48 households.

“They were really happy about the outcome, and it improved their lives on many different levels. They started a little garden next to the pump,” Mugwisi said.

The model: Solar Water Solutions is a hybrid nonprofit and for-profit model that works this way: A rural community will receive a free pump and, with more water, can increase its harvest profits, which will allow it to invest in the next pump in another community. The venture also will sell pump kits that have added functionality for solar-powered lights and Wi-Fi to boarding schools in Zimbabwe. The sale of five kits will fund one nonprofit pump. Operation of the pumps will be supervised by a local committee in the communities, which handles maintenance and security.

Why they do it: Most rural communities use hand-powered pumps, which are labor-intensive and take a long time.

“We realized we could go to existing pumps and retrofit them with solar panels, so now it’s not only pumping water but storing it, so anyone can turn on the faucet and have water,” Munir said.

What’s next: Solar Water Solutions is planning to install seven pumps in Zimbabwe this summer and eventually hire a director to supervise operations there. Next fall, Mugwisi will be working on his PhD at Oxford University as a Rhodes Scholar.

Top photo: Eric Johnson is one of the members of Circle Blue, which will partner with schools, nonprofits and small businesses to find and eliminate waste, saving money and reducing the amount of garbage that goes to the landfills. Photo by Jordan Johnson/W. P. Carey School of Business

Mary Beth Faller

Reporter , ASU News


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ASU, Stanford researchers achieve record-breaking efficiency with tandem solar cell

February 20, 2017

Some pairs are better together than their individual counterparts: peanut butter and chocolate, warm weather and ice cream, and now, in the realm of photovoltaic technology, silicon and perovskite.

As existing solar-energy technologies near their theoretical efficiency limits, researchers are exploring new methods to improve performance — such as stacking two photovoltaic materials in a tandem cell. Collaboration between researchers at Arizona State University and Stanford University has birthed such a cell with record-breaking conversion efficiency — effectively finding the peanut butter to silicon’s chocolate.

The results of their work, published Feb. 17 in Nature Energy, outline the use of perovskite and silicon to create a tandem solar cell capable of converting sunlight to energy with an efficiency of 23.6 percent, just shy of the all-time silicon efficiency record.

“The best silicon solar cell alone has achieved 26.3 percent efficiency,” said Zachary Holman, an assistant professor of electrical engineering at the Ira A. Fulton Schools of Engineering. “Now we’re gunning for 30 percent with these tandem cells, and I think we could be there within two years.”

Silicon solar cells are the backbone of a $30 billion-a-year industry, and this breakthrough shows that there’s room for significant improvement within such devices by finding partner materials to boost efficiency.

The high-performance tandem cell’s layers are each specially tuned to capture different wavelengths of light. The top layer, composed of a perovskite compound, was designed to excel at absorbing visible light. The cell’s silicon base is tuned to capture infrared light.

Perovskite, a cheap, easily manufacturable photovoltaic material, has emerged as a challenger to silicon’s dominance in the solar market. Since its introduction to solar technology in 2009, the efficiency of perovskite solar cells has increased from 3.8 percent to 22.1 percent in early 2016, according to the National Renewable Energy Laboratory.

The perovskite used in the tandem cell came courtesy of Stanford researchers — professor Michael McGehee and doctoral student Kevin Bush, who fabricated the compound and tested the materials.

The research team at ASU provided the silicon base and modeling to determine other material candidates for use in the tandem cell’s supporting layers.

Overcoming challenges with perovskites

Though low-cost and highly efficient, perovskites have been limited by poor stability, degrading at a much faster rate than silicon in hot and humid environments. Additionally, perovskite solar cells have suffered from parasitic absorption, in which light is absorbed by supporting layers in the cell that don’t generate electricity.

“We have improved the stability of the perovskite solar cells in two ways,” said McGehee, a materials science and engineering professor at Stanford’s College of Engineering. “First, we replaced an organic cation with cesium. Second, we protected the perovskite with an impermeable indium tin oxide layer that also functions as an electrode.”

Though McGehee’s compound achieves record stability, perovskites remain delicate materials, making it difficult to employ in tandem solar technology.

“In many solar cells, we put a layer on top that is both transparent and conductive,” said Holman, a faculty member in the School of Electrical, Computer and Energy Engineering. “It's transparent so light can go through and conductive so we can take electrical charges off it.”

This top conductive layer is applied using a process called sputtering deposition, which historically has led to damaged perovskite cells. However, McGehee was able to apply a tin oxide layer with help from chemical engineering professor Stacey Bent and doctoral student Axel Palmstrom of Stanford. The pair developed a thin layer that protects the delicate perovskite from the deposition of the final conductive layer without contributing to parasitic absorption, further boosting the cell’s efficiency.

The deposition of the final conductive layer wasn’t the only engineering challenge posed by integrating perovskites and silicon.

“It was difficult to apply the perovskite itself without compromising the performance of the silicon cell,” said Zhengshan (Jason) Yu, an electrical engineering doctoral student at ASU.

Silicon wafers are placed in a potassium hydroxide solution during fabrication, which creates a rough, jagged surface. This texture, ideal for trapping light and generating more energy, works well for silicon, but perovskite prefers a smooth — and unfortunately reflective — surface for deposition.

Additionally, the perovskite layer of the tandem cell is less than a micron thick, opposed to the 250-micron-thick silicon layer. This means when the thin perovskite layer was deposited, it was applied unevenly, pooling in the rough silicon’s low points and failing to adhere to its peaks.

Yu developed a method to create a planar surface only on the front of the silicon solar cell using a removable, protective layer. This resulted in a smooth surface on one side of the cell, ideal for applying the perovskite, while leaving the backside rough, to trap the weakly absorbed near-infrared light in the silicon.

“With the incorporation of a silicon nanoparticle rear reflector, this infrared-tuned silicon cell becomes an excellent bottom cell for tandems," said Yu.  

Building on previous successes

The success of the tandem cell is built on existing achievements from both teams of researchers. In October 2016, McGehee and post-doctoral scholar Tomas Leijtens fabricated an all-perovskite cell capable of 20.3 percent efficiency. The high-performance cell was achieved in part by creating a perovskite with record stability, marking McGehee’s group as one of the first teams to devote research efforts to fabricating stable perovskite compounds.

Likewise, Holman has considerable experience working with silicon and tandem cells.

“We’ve tried to position our research group as the go-to group in the U.S. for silicon bottom cells for tandems,” said Holman, who has been pursuing additional avenues to create high-efficiency tandem solar cells.

In fact, Holman and Yu published a comment in Nature Energy in September 2016 outlining the projected efficiencies of different cell combinations in tandems.

“People often ask, ‘Given the fundamental laws of physics, what’s the best you can do?’” said Holman. “We’ve asked and answered a different, more useful question: Given two existing materials, if you could put them together, ideally, what would you get?”’

The publication is a sensible guide to designing a tandem solar cell, specifically with silicon as the bottom solar cell, according to Holman.

It calculates what the maximum efficiency would be if you could pair two existing solar cells in a tandem without any performance loss. The guide has proven useful in directing research efforts to pursue the best partner materials for silicon.

“We have eight projects with different universities and organizations, looking at different types of top cells that go on top of silicon,” said Holman. “So far out of all our projects, our perovskite/silicon tandem cell with Stanford is the leader.”

Pete Zrioka

Assistant director of content strategy , Knowledge Enterprise