3D Conjugated Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells and Modules

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Spiro-OMeTAD is a common hole transporting material (HTM) in perovskite solar cells (PSCs).
• Its orthogonal structure provides good conductivity and film formation, but low intrinsic hole mobility due to weak π-π interactions.
• This limits the overall efficiency and stability of PSCs.

Purpose of the Study:

• To design and synthesize a novel HTM, FTPE-ST, with enhanced π-π interactions and high hole mobility.
• To improve the performance and stability of perovskite solar cells (PSCs) by addressing interfacial defects.
• To evaluate the scalability of FTPE-ST for large-area PSCs and modules.

Main Methods:

• Designed FTPE-ST with a twisted dibenzo(g,p)chrysene core and coplanar 3,4-ethylenedioxythiophene (EDOT) donor units.
• Investigated the 3D configuration and conjugated backbone for charge transport and solubility.
• Analyzed the coordination of sulfur donors with lead ions at the perovskite/HTM interface.
• Fabricated and tested PSCs, large-area PSCs, and modules using FTPE-ST.

Main Results:

• FTPE-ST exhibits enhanced π-π interactions, high hole mobility, and excellent solubility.
• PSCs utilizing FTPE-ST achieved a champion power conversion efficiency (PCE) of 25.21% with superior long-time stability.
• The sulfur donors in FTPE-ST effectively suppressed defects at the perovskite/HTM interface.
• Large-area (1.0 cm²) PSCs and modules (29.0 cm²) demonstrated high PCEs of 24.21% and 21.27%, respectively.

Conclusions:

• FTPE-ST is a highly effective non-spiro HTM for n-i-p perovskite solar cells.
• The novel molecular design overcomes the limitations of traditional HTMs, leading to record efficiencies.
• FTPE-ST shows significant potential for the commercialization of stable and efficient large-scale perovskite solar cells and modules.