Improved hole interfacial layer for planar perovskite solar cells with efficiency exceeding 15%

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Planar perovskite solar cells (PSCs) offer efficient, low-temperature fabrication.
• Controlling interfaces and crystal growth is crucial for high-performance PSCs.

Purpose of the Study:

• To introduce a novel PEDOT-GeO2 composite as a hole transport layer (HTL) for planar PSCs.
• To investigate the effect of GeO2 nanoparticles on perovskite film formation and device performance.

Main Methods:

• Solution-processed PEDOT-GeO2 composite films were prepared by incorporating GeO2 aqueous solution into PEDOT aqueous dispersion.
• The composite film was used as an HTL in planar PSCs.
• Perovskite film growth and morphology were analyzed.

Main Results:

• The PEDOT-GeO2 composite exhibited high conductivity, ambient stability, and effective interface modification.
• GeO2 particles acted as nucleation sites, promoting the growth of uniform CH3NH3PbI(3-x)Cl(x) films with large domains.
• The resulting PSCs achieved a maximum power conversion efficiency (PCE) of 15.15% and a fill factor (FF) of 74%.

Conclusions:

• The PEDOT-GeO2 composite HTL significantly enhances perovskite crystallization and device performance.
• This method offers a promising strategy for developing efficient and stable planar PSCs.
• A remarkable average PCE improvement of ~37% was observed compared to pristine PEDOT devices.