Nankai University's Groundbreaking Achievement in Perovskite Solar Technology

In a significant advancement for renewable energy research, scientists at Nankai University in Tianjin, China, have developed a perovskite solar cell (PSC) that achieves a certified steady-state power conversion efficiency (PCE) of 27.17 percent. This record-breaking performance, detailed in a paper published in Nature, marks the highest efficiency yet for n-i-p structured PSCs, a conventional architecture prized for its scalability in manufacturing. The innovation centers on a continuously graded-doped tin dioxide (SnO2) electron transport layer (ETL), which addresses longstanding issues like non-radiative recombination at the ETL-perovskite interface.

This breakthrough not only pushes the boundaries of photovoltaic technology but also underscores Nankai University's pivotal role in China's drive toward energy innovation. As one of the nation's top research institutions, Nankai continues to lead in new energy materials chemistry, aligning with national goals for carbon neutrality by 2060.

What Are Perovskite Solar Cells and Why Do They Matter?

Perovskite solar cells derive their name from the crystal structure of the light-absorbing material, resembling the mineral perovskite (calcium titanium oxide). These hybrid organic-inorganic lead or tin halide perovskites offer several advantages over traditional silicon-based solar cells: they are low-cost to produce, lightweight, flexible, and capable of high efficiencies through solution processing rather than energy-intensive high-temperature fabrication.

Discovered in 2009 with initial efficiencies below 4 percent, PSCs have rapidly climbed the learning curve. By 2026, lab efficiencies exceed 27 percent for single-junction cells, approaching silicon's Shockley-Queisser limit of around 29 percent for single-junction devices. However, commercial viability hinges on stability and scalability—issues where n-i-p structures excel due to their compatibility with industrial roll-to-roll printing.

In China, where solar manufacturing dominates globally (over 80 percent market share), perovskites represent the next frontier. Government initiatives like the 14th Five-Year Plan prioritize third-generation photovoltaics, funneling billions into R&D at universities like Nankai to diversify beyond crystalline silicon.

The Technical Innovation: Graded-Doped SnO2 ETL

The Nankai team's key contribution is a ligand-competitive binding method to create a continuously graded n+/n-doped SnO2 ETL. Traditional SnO2 layers suffer from band misalignment and electron accumulation at the interface with the perovskite absorber, leading to recombination losses that cap steady-state PCE at about 26 percent.

Step-by-step, the process involves:

• Solution synthesis of SnO2 nanoparticles with varying ligand densities for n+ (high doping) and n (low doping) regions.
• Ligand-competitive binding during deposition, forming a gradient where doping decreases from the substrate to the perovskite interface.
• This gradient establishes a built-in electric field, aligning energy bands, accelerating electron extraction, and suppressing recombination.

Result: Voc up to 1.22 V, FF of 84.5 percent, Jsc of 26.5 mA/cm², yielding 27.17 percent steady-state PCE—verified by independent labs. For larger areas, 1 cm² cells hit 25.79 percent, and a 16 cm² module 23.33 percent, demonstrating scalability.

The Research Team Behind the Record

Led by corresponding authors Mingjian Yuan and Jun Chen from Nankai's College of Chemistry, first author Di Wang spearheaded the ETL development. Yuan, vice dean with expertise in perovskite optoelectronics, has a track record of high-impact publications. Chen, an academician, heads energy chemistry efforts at the State Key Laboratory for Advanced Energy Materials Chemistry.

The team spans Nankai's interdisciplinary centers, including the Frontiers Science Center for New Organic Matter and Haihe Laboratory. Collaborators include Beijing Institute of Technology and international partners from Saudi Arabia and Denmark, reflecting Nankai's global outlook.

This collaborative model exemplifies how Chinese universities foster talent through national labs and youth funds, training PhD students like Wang in cutting-edge photovoltaics.

Nankai University's Strengths in Energy Materials Research

Located in Tianjin, Nankai University—one of China's C9 League elites—boasts over 30,000 students and excels in chemistry (top 1 percent globally). The College of Chemistry hosts key labs for energy materials, driving breakthroughs in batteries, solar cells, and electrocatalysis.

Nankai's Institute of New Energy Material Chemistry, established 1992, pioneered organic solar cells and now leads in perovskites. Recent feats include solid-state batteries for 1,000 km range and flexible topological lasers, positioning it as a hub for sustainable tech.

Funding from NSFC, MOST, and Tianjin supports 100+ researchers, emphasizing commercialization—vital for China's dual-carbon goals.

China's Leadership in Perovskite Solar Cell Development

China dominates perovskite R&D, with universities like USTC, Huazhong UST, and Nankai holding multiple records. In 2026, Chinese labs claim over 70 percent of top efficiencies per NREL charts. Massive state investment—hundreds of billions in renewables—fuels pilot lines aiming GW-scale production by 2030.

This aligns with 1,200 GW solar capacity target by 2030, where perovskites could cut costs 50 percent vs. silicon, enabling BIPV and flexible applications.

Scalability: From Lab to Modules

Beyond small cells, Nankai's approach scales: 23.33 percent PCE on 16 cm² modules via blade-coating. This n-i-p compatibility with textured substrates suits mass production, unlike finicky p-i-n inverted structures.

• Low-temperature processing (<150°C).
• Compatible with flexible substrates for wearables.
• Potential tandem with silicon for >30 percent.

China's supply chain—perovskite precursors to encapsulation—positions it for rapid deployment.

Challenges Remaining in Perovskite Commercialization

Despite records, lead toxicity, humidity sensitivity, and hysteresis persist. Nankai's SnO2 gradient mitigates interface issues but long-term stability (1,000+ hours) needs validation. Regulations and recycling loom large.

China addresses via tin-based alternatives and encapsulation advances.

Implications for Higher Education and Talent in China

This feat highlights China's university ecosystem: Project 985/211 funding, Thousand Talents attracting overseas experts like Yuan (ex-Toronto). Nankai trains 1,000+ energy PhDs yearly, feeding firms like LONGi, Trina Solar.

It inspires STEM enrollment, with renewables curricula booming amid 18 million annual grads.

Global Impact and Future Outlook

Nankai's record accelerates perovskite tandems toward 35 percent, slashing LCOE below $0.02/kWh. For China, it bolsters energy security amid import reliance.

Future: Yuan's group eyes stability >10 years, commercialization via spin-offs. Collaborations with Saudi, Danish partners globalize tech transfer.

As Nankai exemplifies, Chinese universities are reshaping photovoltaics, driving sustainable future.

Photo by Jakob Rosen on Unsplash