Polymer Solar Cells with 90% External Quantum Efficiency Featuring an Ideal Light- and Charge-Manipulation Layer

Area of Science:

• Materials Science
• Nanotechnology
• Photovoltaics

Background:

• Polymer solar cells (PSCs) require optimized power conversion efficiency (PCE).
• Key factors include matching the solar spectrum, maximizing light absorption, and minimizing charge recombination.
• Advanced materials and device architectures are crucial for progress.

Purpose of the Study:

• To develop an efficient light- and charge-manipulation layer (LCML) for polymer solar cells (PSCs).
• To investigate the role of a nanopatterned ZnO:Al2O3 composite film in enhancing device performance.
• To demonstrate the effectiveness of this LCML in improving both light harvesting and charge collection.

Main Methods:

• Fabrication of a nanopatterned ZnO:Al2O3 composite film as an LCML.
• Utilizing Al2O3 shells on ZnO nanoparticles for passivation and electron collection.
• Characterizing the optical and electronic properties of the composite film.
• Fabricating and testing single-junction PSCs with the developed LCML.

Main Results:

• The ZnO:Al2O3 LCML demonstrated broadband light harvesting due to increased refractive index and nanostructure.
• Al2O3 shells effectively passivated ZnO nanoparticles, suppressing charge recombination and improving electron collection.
• Highly efficient single-junction PSCs achieved peak external quantum efficiencies up to 90%.
• Certified power conversion efficiencies (PCEs) reached 9.69% for a fullerene blend (PTB7:PC71BM) and 13.03% for a nonfullerene blend (FTAZ:IDIC).

Conclusions:

• The nanopatterned ZnO:Al2O3 composite film serves as an effective LCML for PSCs.
• This approach significantly enhances light harvesting and charge transport, leading to higher PCEs.
• The developed LCML shows great potential for future photovoltaic applications, unlocking the full capabilities of PSCs.