Understanding Perovskite Solar Cells and Their Promise

Perovskite solar cells represent one of the most exciting developments in renewable energy technology. Named after the crystal structure resembling the mineral perovskite, these devices use hybrid organic-inorganic lead or tin halide-based materials as light absorbers. Unlike traditional silicon solar panels, which dominate the market but require high temperatures and energy-intensive manufacturing, perovskite solar cells can be produced via low-cost solution processing at near-room temperature. This makes them potentially cheaper and easier to scale.

In Singapore, where land scarcity drives the need for efficient urban solar solutions, research into perovskites aligns perfectly with national goals for sustainable energy. Nanyang Technological University, a global leader in materials science, has been at the forefront, pushing efficiencies beyond 25 percent while tackling key hurdles like long-term durability.

The Stability Challenge in Perovskite Technology

Despite lab efficiencies rivaling silicon at over 26 percent certified, perovskite solar cells suffer from instability under real-world conditions. Factors like moisture, heat, light, and ion migration degrade the material, causing efficiency drops within months. The active layer's sensitivity stems from defects at interfaces between the perovskite and charge transport layers, leading to non-radiative recombination and hysteresis.

Low-dimensional perovskite interfaces, such as 2D or quasi-2D layers formed by bulky organic cations like phenethylammonium (PEA), have been used as protective caps. However, these are metastable and reactive, exchanging ions with the 3D perovskite bulk, which undermines passivation over time. Singapore's humid tropical climate exacerbates these issues, making robust interfaces critical for local applications like building-integrated photovoltaics.

NTU's Innovative Selective Templating Growth Method

NTU researchers, led by Associate Professor Teddy Salim from the School of Materials Science and Engineering and Professor Tze Chien Sum from the School of Physical and Mathematical Sciences, introduced selective templating growth (STG). This elegant solution starts with a conventional metastable low-dimensional interface, typically PEA-based, deposited on the 3D perovskite surface.

Next, precursors of bulky, low-reactivity cations like iso-butylammonium (isoBA) or neo-pentylammonium (neoPA) are drop-cast in an orthogonal solvent that doesn't dissolve the underlying perovskite. Through cation exchange, the metastable layer templates the epitaxial growth of a stable, chemically inert low-dimensional cap. This new layer passivates defects without reacting further, maintaining high hole extraction while blocking degradation pathways.

• Step 1: Fabricate standard 3D perovskite film (e.g., FAPbI3-based).
• Step 2: Spin-coat metastable LD precursor (PEAI).
• Step 3: Anneal to form LD template.
• Step 4: Drop-cast bulky cation precursor solution.
• Step 5: Exchange and grow CI LD interface; rinse excess.

This process is scalable, compatible with roll-to-roll printing, and avoids toxic solvents.

Impressive Performance Metrics from NTU Devices

The STG-capped inverted perovskite solar cells achieved a power conversion efficiency of 25.1 percent over 1.235 square centimeters—one of the highest for devices of this size. Voc was 1.20 V, Jsc 25.4 mA/cm², FF 82.3 percent.

Stability tests shone: Devices retained 93 percent initial efficiency after 1000 hours maximum power point tracking under one-sun illumination at 25 percent relative humidity. Under thermal stress at 85 degrees Celsius, they held 98 percent after 1100 hours. Unencapsulated cells endured 2000 hours at 65 degrees Celsius with 90 percent retention, far surpassing controls.

Compared to PEA-only caps, STG reduced non-radiative losses, boosted photoluminescence lifetime to 1.2 microseconds, and minimized hysteresis. These metrics position NTU's work as a benchmark for commercialization.

NTU's Research Ecosystem Driving Solar Innovation

Nanyang Technological University, consistently ranked among the world's top young universities, hosts world-class facilities like the Nanyang Environment & Water Research Institute and Energy Research Institute @ NTU. The breakthrough emerged from interdisciplinary collaboration across Materials Science, Physics, and Engineering schools, supported by the Facility for Analysis, Characterisation, Testing and AstrOsciences (FACT).

Singapore's higher education landscape amplifies such advances. With heavy investments via the National Research Foundation's Research, Innovation and Enterprise 2025 Plan, NTU secured Ministry of Education Academic Research Fund Tier 1, 2, and 3 grants, plus Competitive Research Programme funding. This ecosystem fosters PhD training, postdoctoral positions, and industry spin-offs, positioning Singapore as an Asia-Pacific hub for next-gen photovoltaics.

Funding and Collaborative Efforts Behind the Breakthrough

The project drew from multiple sources, including Singapore NRF Fellowship (NRF-NRFF13-2023-0005), A*STAR TSARP, and MOE Tier 2 grant (MOE-T2EP20220-0006). Patents filed by NTU protect the STG method, signaling commercialization potential through tech transfer offices.

Collaborations extend to international partners, with data shared openly via DR-NTU repository. In Singapore, NTU complements NUS's perovskite work on tandem cells, creating synergies under the Solar Energy Research Institute of Singapore.

Career Opportunities in Perovskite Research at Singapore Universities

This breakthrough highlights vibrant career paths in Singapore's higher education. NTU frequently recruits research fellows, associates, and faculty in materials science and energy engineering. Roles involve fabricating devices, characterizing interfaces via SEM, XPS, TRPL, and advancing to tandem or flexible PSCs.

PhD students gain hands-on experience in cleanrooms, publishing in top journals like Nature Energy. Salaries competitive: Research fellows earn SGD 60,000-90,000 annually, professors SGD 200,000+. Singapore's pro-research environment offers grants, housing subsidies, and global networks, attracting talents worldwide.

• Research Associate: Focus on device optimization.
• Postdoc: Lead stability studies.
• Faculty: Develop courses in sustainable energy.

Singapore's Green Energy Goals and Perovskite's Role

Singapore aims for 2 gigawatts solar capacity by 2030 under the Singapore Green Plan 2030, despite limited rooftop space. High-efficiency perovskites enable denser installations, reducing import dependence amid geopolitical tensions.

NTU's advance supports national RIE2025, targeting SGD 25 billion R&D investment. Tandem silicon-perovskite cells could hit 30 percent efficiency, slashing levelized cost of electricity. Local firms like Vanda Gold or Sunseap eye commercialization.

Expert Insights and Quotes from NTU Researchers

"The STG strategy is a game-changer, balancing passivation and conductivity without compromising scalability," says Assoc Prof Teddy Salim. Prof Sum Tze Chien adds, "By templating stable inert layers, we've unlocked a pathway to durable PSCs viable for Singapore's humid conditions."

Haixia Rao, first author, notes the method's simplicity: "Drop-casting in minutes yields superior interfaces." Peers praise the work's rigor, with DFT simulations confirming energetics.

Future Directions and Global Implications

NTU plans tandem integrations and flexible modules for wearables or BIPV. Challenges remain: Scale-up uniformity, lead alternatives, recycling. Yet, STG's versatility suits diverse cations, accelerating progress.

For Singapore universities, this cements leadership in clean energy, inspiring students toward research careers. Globally, it addresses climate urgency, potentially cutting solar costs 30-50 percent.

Photo by Newpowa on Unsplash

Student and Early-Career Opportunities at NTU

NTU offers modules like MSE graduate perovskite courses, internships via ERI@N, and scholarships like Nanyang President's. Undergrads join labs through URECA, gaining publications. Singapore's ecosystem includes A*STAR fellowships, ideal for aspiring researchers.