Hydroxymethyl-Functionalized PEDOT-MeOH:PSS for Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Polymer Chemistry

Background:

• Perovskite solar cells (PVSCs) are a promising renewable energy technology.
• Efficient hole transport materials (HTMs) are crucial for high-performance inverted PVSCs.
• Commercial PEDOT:PSS, a common HTM, has limitations in energy level alignment and conductivity.

Purpose of the Study:

• To synthesize and characterize a novel conducting polymer, poly(hydroxymethylated-3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT-MeOH:PSS).
• To investigate the impact of PEDOT-MeOH:PSS as a hole transport material in inverted PVSCs.
• To enhance the performance of inverted PVSCs through improved energetic alignment and conductivity.

Main Methods:

• Synthesis of PEDOT-MeOH:PSS by functionalizing ethylenedioxythiophene (EDOT) with hydroxymethyl groups.
• Modification of PEDOT-MeOH:PSS properties by adjusting PSS content, ferric oxidizing agent, and post-synthesis ethylene glycol treatment.
• Incorporation of the modified PEDOT-MeOH:PSS into inverted PVSC architectures and performance evaluation.

Main Results:

• The hydroxymethyl functionalization lowered the highest occupied molecular orbital of PEDOT-MeOH, increasing the work function of PEDOT-MeOH:PSS.
• Hydrogen bonding in PEDOT-MeOH:PSS promoted chain growth and enhanced PSS doping, improving electronic and microstructural properties.
• PVSCs utilizing ethylene-glycol-treated PEDOT-MeOH:PSS demonstrated superior performance compared to those with commercial PEDOT:PSS.

Conclusions:

• PEDOT-MeOH:PSS offers better energetic alignment and enhanced electrical conductivity for inverted PVSCs.
• The developed material significantly overperforms commercial PEDOT:PSS in inverted PVSC applications.
• This research paves the way for advanced HTMs to achieve highly efficient inverted PVSCs.