Solution-processed nickel acetate as hole collection layer for polymer solar cells.

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Polymer solar cells (PSCs) are a promising renewable energy technology.
• Poly(3-hexylthiophene) (P3HT) and indene-C(60) bisadduct (ICBA) are common materials for PSCs.
• Poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is a widely used hole collection layer (HCL) but suffers from acidity and instability.

Purpose of the Study:

• To investigate the use of water-soluble nickel acetate (NiAc) as an alternative HCL in P3HT/ICBA based PSCs.
• To evaluate the performance and properties of NiAc as an anode buffer layer.
• To explore new materials for more efficient and stable PSCs.

Main Methods:

• Fabrication of PSCs using P3HT:ICBA active layers.
• Application of a thermally annealed NiAc (α-NiAc) layer as the HCL.
• Characterization of α-NiAc optical and electrical properties, including transparency and hole mobility.
• Performance testing of PSCs under AM1.5G illumination.

Main Results:

• The α-NiAc layer exhibited higher transparency than PEDOT:PSS in the 500-900 nm range.
• α-NiAc demonstrated a high hole mobility of 1.3 × 10⁻³ cm²/V·s.
• PSCs with α-NiAc achieved a power conversion efficiency of 6.08%, comparable to state-of-the-art P3HT-based devices.

Conclusions:

• Water-soluble NiAc is a viable and efficient alternative to PEDOT:PSS as an HCL in PSCs.
• The α-NiAc layer offers improved optical properties and high hole mobility.
• This finding provides a new material option for designing higher efficiency and more stable polymer solar cells.