New Pathway Emerges To Improve Polycrystalline Thin-Film Solar Cell Performance
Puzzling out and testing new ways to improve the efficiency of cadmium telluride (CdTe) polycrystalline thin-film photovoltaic materials is a typical day in the life of National Renewable Energy Laboratory (NREL) research scientists Matthew Reese and Craig Perkins. Like any good puzzlers, they bring curiosity and keen observation to the task. These skills led them, over time, to make an intriguing observation. In fact, their discovery may prove to be a boon for the next generation of several different types of thin-film solar cells.
When fragments of solar cell material are crystallized together, or “grown” — think of a piece of rock candy growing in layers in a cup of sugar — they create a polycrystalline solar cell. With many layers come many surfaces, where one layer ends and another begins. These surfaces can cause defects that restrict the freedom of electrons to move, reducing the cell’s efficiency. As the cells are grown, researchers can introduce specific compounds that minimize the loss of electrons at these defects, in a process called “passivation.”
Reese, Perkins, and Colorado School of Mines doctoral student Deborah McGott noticed that the three-dimensional (3D) CdTe solar cells’ surfaces appeared to be covered in a very thin, two-dimensional (2D) layer that naturally eliminated surface defects. This 2D passivation layer forms in sheets on the 3D light-absorbing layer as the cell is growing, in a standard processing technique that is used around the globe. Despite the ubiquity of this 2D passivation layer, it had not been observed or reported in the research literature. Reese, Perkins, and McGott believed 2D passivation was also occurring naturally in other thin-film solar cells, like copper indium gallium selenide (CIGS) and perovskite solar cells (PSCs). They realized that this observation could lead to the development of new methods to improve the performance of many types of polycrystalline thin-film cells.
To confirm their hypothesis, they discussed it with NREL colleagues in the CdTe, CIGS, and PSC research groups. Through many informal discussions involving coffee, hallway chats, and impromptu meetings, Reese, Perkins, and McGott arrived at an “aha” moment. Their CdTe and CIGS colleagues confirmed that, while their research communities were not generally trying to perform 2D surface passivation in the 3D light-absorbing layer, it was, in fact, occurring. The PSC researchers said that they had noticed a 3D/2D passivation effect and were beginning to intentionally include compounds in device processing to improve performance. The “aha” moment took on even more significance.
“One of the unique things about NREL is that we have large groups of experts with different pools of knowledge working on CdTe, CIGS, and PSC technologies,” Reese said. “And we talk to each other! Confirming our hypothesis about naturally occurring 3D/2D passivation with our colleagues was easy because we share the successes and setbacks of our diverse research in an ongoing, informal, and collaborative way. We learn from each other. It is not something that typically happens in academic or for-profit-based polycrystalline thin-film solar cell research, where information is closely held, and researchers tend to remain siloed in their specific technology.”
The details of Reese, Perkins, and McGott’s discovery are presented in the article “3D/2D passivation as a secret to success for polycrystalline thin-film solar cells,” published in the journal Joule.
Supporting Evidence in the Literature
To confirm their findings, McGott conducted an extensive literature search and found considerable supporting evidence. The literature confirmed the presence of passivating 2D compounds in each of the CdTe, CIGS, and PSC technologies. No mention was made, however, of the 2D compounds’ ability to improve device performance in CdTe and CIGS technologies. While many articles on PSC technologies noted the naturally occurring 3D/2D passivation effect and discussed efforts to intentionally include specific compounds in device processing, none suggested that this effect might be active in other polycrystalline thin-film photovoltaic technologies.
Polycrystalline thin-film solar cells are made by depositing thin layers, or a thin film, of photovoltaic material on a backing of glass, plastic, or metal. Thin-film solar cells are inexpensive, and many people are familiar with their more unique applications. They can be mounted on curved surfaces — to power consumer goods, for example — or laminated on window glass to produce electricity while letting light through. The largest market for thin-film solar cell applications, however, is for CdTe thin film on rigid glass to make solar modules. CdTe modules are deployed at utility scale, where they compete directly with conventional silicon solar modules. Currently, commercial thin-film modules are generally less efficient than the best single crystal silicon solar modules, making performance improvements a high priority for polycrystalline thin-film researchers.
Key Properties of 2D Materials
Reese, Perkins, and McGott’s team used surface science techniques combined with crystal growth experiments to show that the 2D layers existed at and passivated 3D absorber surfaces in the three leading polycrystalline thin-film photovoltaic technologies. They then analyzed the key properties of successful 2D materials and developed a set of principles for selecting passivating compounds.
Finally, the team outlined key design strategies that will allow 3D/2D passivation to be employed in polycrystalline thin-film photovoltaic technologies more generally. This is particularly important because each 3D material requires a specific passivation approach.
The literature results, combined with lab-based observations, show that 3D/2D passivation may be the secret to success in enabling next-generation thin-film solar cells, particularly if researchers freely share the knowledge developed for each technology. The lack of 3D/2D passivation may even shed light on the stalled performance improvements of some polycrystalline technologies such gallium arsenide. By drawing parallels between the three technologies, Reese, Perkins, and McGott hope to demonstrate how the knowledge developed in each can — and should — be leveraged by other technologies, an approach that is seldom seen in polycrystalline thin-film solar cell research.
CdTe, CIGS, and PSC thin-film research at NREL is funded by the Department of Energy’s Solar Energy Technologies Office. Additional funding for Reese and McGott’s research is provided by the Department of Defense’s Office of Naval Research.
Learn more about photovoltaic research at NREL.
Article courtesy of the NREL, The U.S. Department of Energy.
Environment
Kia’s first electric hatchback is here and it has nearly 400 miles range: Meet the EV4 hatch
Who said hatchbacks are going out of style? Kia’s first electric hatchback, the EV4, went on sale in the UK on Monday, offering the longest driving range of any of its EVs to date. Here’s a full breakdown of prices and specs.
Meet the EV4, Kia’s first electric hatchback
After launching the sedan version in Korea in April, the EV4 already took the top spot as the best-selling domestic electric sedan in its second month on the market. It’s already being called a “box office hit.” Now, the new hatch variant is officially on sale.
Kia opened orders for the EV4 hatchback in the UK on Monday, starting from £34,695 ($47,700). The EV4 is Kia’s first crack at an electric hatchback.
With an impressive 388 miles of WLTP driving range, it’s also the longest driving range of any EV Kia has ever produced.
The hatch is based on the same E-GMP platform as the EV4 sedan and Kia’s other electric vehicles, but it’s custom-tailored for European buyers.
The base EV4 “Air” is available with two battery packs: 58.2 kWh or 81.4 kWh, providing a WLTP driving range of up to 273 miles or 388 miles on a full charge. Kia said it’s the brand’s first electric vehicle offering a range of over 380 miles.
The sporty “GT-Line” and top-spec “GT-Line S” variants are available exclusively with the extended range (81.4 kWh) battery, which offers a range of 362 miles.
All EV4 hatchback models are powered by a single front motor with 201 bhp (150 kW) and 283 Nm of torque, good for a 0 to 62 mph sprint in 7.5 secs.
The interior features a similar setup to Kia’s latest EV models, like the EV3 and EV9, with its new connected car Navigation Cockpit (ccNC) at the center. The setup features dual 12.3″ driver clusters and infotainment screens in a curved panoramic display. An additional 5.3″ touchscreen for climate control is included for easy access to heating and ventilation functions.
Like the EV3, Kia’s electric hatchback will include an AI Assistant, powered by ChatGPT. It will also be the brand’s first vehicle with several entertainment settings, including “Rest mode” and Theatre mode.”
With all the seats upright, the electric hatch has a boot space of 435 liters, which Kia claims makes it “one of the most practical vehicles in its segment.”
With a length of 4,430 mm, a width of 1,860 mm, and a height of 1,485 mm, the EV4 hatchback is about the size of Kia’s XCreed.
The EV4 hatch can recharge from 10% to 80% in 29 minutes, while the larger battery will take approximately 31 minutes to charge using a 350 kW DC fast charger.
| Kia EV4 hatchback trim | Starting Price | Driving Range (WLTP) |
| Air Standard Range | £34,695 ($47,700) | 273 miles |
| Air Long Range | £37,695 ($51,700) | 388 miles |
| GT-Line | £39,395 ($54,000) | 362 miles |
| GT-Line S | £43,895 ($60,200) | 362 miles |
Kia opened orders for the new electric hatch on Monday, July 1. It will join the EV3, EV6, and EV9 in the brand’s European lineup. The EV4 hatchback will be built at Kia’s plant in Slovakia to expedite deliveries, which are scheduled to begin in the Fall.
Kia also announced on Monday that a new EV4 Fastback variant will join the lineup, but didn’t offer any additional details. More info, including prices and specs, “will be revealed in due course.” Check back soon for the latest.
What do you think of Kia’s first electric hatchback? Would you buy one in the US? Unfortunately, it’s not likely to make the trip overseas, but we will see the sedan version launch at some point in early 2026. Let us know your thoughts in the comments.
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Tesla (TSLA) is about to release its Q2 2025 delivery and production results. Here, we examine what Wall Street expects and what would make sense in reality.
Wall Street has struggled to understand Tesla’s decline in deliveries over the past year.
The analyst consensus for the first quarter was over 450,000 deliveries in January, but that number dropped to 377,000 deliveries by the end of the quarter.
They had to adjust down by 73,000 units, or about $3 billion in sales, over just two months, and they still got it wrong by more than 40,000 units.
Something similar is happening this quarter.
The Wall Street consensus was for 444,000 deliveries in April, indicating that analysts believed Tesla when it stated that the poor performance in the first quarter was solely due to the Model Y changeover and that it could return to growth or maintain demand, as it had delivered approximately 444,000 vehicles in Q2 2024.
However, that consensus waned throughout the quarter as data confirmed that Tesla is not production-constrained, yet still faces significant demand issues.
The Wall Street consensus for Tesla’s Q2 deliveries is now at 385,000 vehicles.
This represents a 13% decline year-over-year, despite Tesla currently offering record discounts and incentives, including 0% financing on both the Model 3 and Model Y in most markets.
However, it is likely that analysts are again overestimating deliveries.
Electrek’s Take
We have great data in Europe and China, where Tesla is basically down by a few thousand units despite the new Model Y being widely available during the second quarter.
The only primary market with limited data for the second quarter is the US.
The US is likely where the new Model Y had the biggest positive impact, and Tesla will need to perform well there for deliveries to surpass its Q1 2025 results.
The automaker has no chance at annual growth in the second quarter, but based on the best data available, I think it should end between 330,000 and 360,000 units – way below the current analyst consensus.
The lower end of the spectrum would result in a massive 25% drop in annual deliveries, while the higher end would result in a still significant 19% drop.
There’s no other way to cut it: Tesla’s automotive business is in crisis.
The crazy thing is that Wall Street is completely missing this story and only adjusting for the decline throughout the quarter.
At the end of the first quarter, analysts still expected Tesla to avoid a decline in deliveries in 2025, with approximately 1,850,000 vehicles.
The consensus now stands at 1.6 million units, which is still likely too high by 100,000 units, representing billions of dollars in sales.
Furthermore, they predict that Tesla will experience a resurgence in growth in 2026, despite the EV tax credit being eliminated in the US, its least affected market so far.
Tesla has minimal prospects for returning to automotive growth beyond some significant reforms that are nowhere in sight, given Musk’s leadership.
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Tesla’s stock (TSLA) crashed by as much as 5% in pre-market trading after President Trump threatened to set DOGE on Elon Musk, who has been criticizing his ‘Big Beautiful Bill’.
After being kindly shown the door to the White House last month, Musk had a brief moment of clarity and started to criticize Trump and the Republican party, which he helped elect with almost $300 million of his own money in the 2024 elections.
He highlighted how Trump’s “Big Beautiful Bill” is expected to increase the deficit and debt. The Tesla CEO even linked Trump to Jeffrey Epstein, something that has been well known for decades, but Musk conveniently ignored it as he was backing the President and wearing hats that read, “Trump was right about everything.”
Musk quickly calmed down and even apologized for “going too far” and started praising Trump again.
That didn’t last long.
Over the last few days, as the Senate attempts to pass Trump’s budget and tax bill, Musk has renewed his efforts to halt the legislation.
The CEO appeared to renew the attacks after the Senate updated the bill to kill the EV incentive sooner and to increase taxes on solar and wind projects.
However, Musk said that he doesn’t mind EV and renewable energy subsidies going away, but he believes that fossil fuel subsidies should also be removed, which is not in the plans at all.
Trump campaigned on Musk’s money, claiming that he would get America to “drill, baby, drill” again.
The CEO went as far as threatening any Senator who vote for the bill, all Republicans, to face his money in their next primary. He added that if the bill passes, he will create a new “America Party.’
Musk’s attacks have focused on the bill itself and the Republicans voting for it, but Trump likes to call it his bill, and unsurprisingly, he is unhappy with Musk.
Last night, he took to Truth Social to highlight again that Musk “would probably have to close up shop and head back to South Africa” without US government subsidies.
The President then suggested that he could have DOGE, a department that Musk created, go after him and the subsidies that his companies get:
Elon Musk knew, long before he so strongly Endorsed me for President, that I was strongly against the EV Mandate. It is ridiculous, and was always a major part of my campaign. Electric cars are fine, but not everyone should be forced to own one. Elon may get more subsidy than any human being in history, by far, and without subsidies, Elon would probably have to close up shop and head back home to South Africa. No more Rocket launches, Satellites, or Electric Car Production, and our Country would save a FORTUNE. Perhaps we should have DOGE take a good, hard, look at this? BIG MONEY TO BE SAVED!!!
Tesla’s stock dropped by more than 4% in pre-market trading following the President’s threat.
Musk responded to the President by pointing out that he is asking to remove the subsidies, but he didn’t add his usual caveat of also removing all subsidies for fossil fuel.
Electrek’s Take
It’s both sad and funny to see Elon now. It’s sad because the US is plunging back into an energy dark age of relying on fossil fuels. Still, it’s amusing because Elon is acting as if he’s just now realizing what he has done, despite everyone but a few cult members screaming at him that this was going to happen for the last year.
Elon got what he wanted out of Trump with his $300 million, and now, he realizes that his influence has limits and that Trump is going to do way more damage than just what Musk wanted out of him: to stop illegal immigration and the so scary “woke mind virus.”
The result will be a significant blow to the growth of electric vehicles and clean energy in the US, and Tesla will be affected in the process, exactly what we have been saying for the last year.
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