In May 2023, the journal Nature featured a cover article highlighting a breakthrough in flexible monocrystalline silicon solar cells developed by researchers at the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences. The innovation achieved a device thickness of just 60 micrometers (1/15th the thickness of an A4 sheet), a bending radius under 5 mm, and a bending angle exceeding 360°, all while maintaining a 26.8% power conversion efficiency. This advancement addresses the longstanding mechanical brittleness challenge of monocrystalline silicon.
Technological Breakthrough
The team employed a mesoscopic symmetry modulation strategy, combining wet-chemical etching and dry plasma etching to smooth edges, transforming traditional V-shaped defects (with a stress concentration factor, Kt≈3.2) into U-shaped structures (Kt≈1.1). Finite element analysis revealed a 37% reduction in maximum strain, while molecular dynamics simulations confirmed a shift from brittle fracture to elastoplastic secondary shear band fracture, enhancing fracture toughness to 2.8 MPa·m¹/². The process targets only the 20-50 μm edge region, preserving >99.5% crystal integrity in core photovoltaic areas.
Applications and Prospects
- Aerospace: Deployed in near-space vehicles, the technology reduces module areal density to 0.6 kg/m² (40% of conventional modules), improves surface conformity to 98%, and achieves 320 W/m² power density.
- Building-Integrated Photovoltaics (BIPV): Enables curved installations with radii >0.5 m. A pilot curtain wall project demonstrated 24.3% efficiency and 300 MWh annual generation.
- Mobile Energy: Automotive systems generate 2.3 kWh daily with 180 Wh/kg energy density; wearable devices reach 15 mW/cm² power density.
- Extreme Environments: Deployed at Antarctic research stations, the technology exhibits <5%/year efficiency degradation (vs. >15% for conventional modules).
Industrialization Progress
- Mass Production: Thinning processes achieve >95% yield and <0.3% breakage rates, reducing manufacturing costs by 18%.
- Tandem Technology: Combined with perovskite materials, the technology achieves 28.7% certified efficiency (Jsc=42.1 mA/cm², Voc=1.89 V).
- Policy Support: China’s 2025 distributed PV target of 150 GW aims for 15% flexible module penetration.
Challenges and Future Development
Current bottlenecks include low silicon recycling rates (<10%) and high processing costs for ultrathin wafers (<30 μm). The team’s selective chemical stripping technique boosts silicon recovery to 95%, while non-contact laser cutting may reduce wafer thickness to 20 μm. GW-scale production is anticipated by late 2026, pending resolution of thickness fluctuations and increased breakage risks in ultrathin wafers.
