Efficient, stable and scalable perovskite solar cells using poly(3-hexylthiophene)

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells commonly use poly(triarylamine) (PTAA) or spiro-OMeTAD as hole-transport materials, but these face commercialization challenges due to cost and dopant-induced degradation.
• Poly(3-hexylthiophene) (P3HT) offers a low-cost, easily fabricated alternative with good optoelectronic properties, but its use in perovskite solar cells has been limited to efficiencies around 16%.

Purpose of the Study:

• To develop a dopant-free device architecture for highly efficient perovskite solar cells utilizing P3HT as the hole-transport material.
• To overcome the efficiency limitations of P3HT in perovskite solar cells and enhance device stability.

Main Methods:

• A novel device architecture was proposed, incorporating a thin wide-bandgap halide perovskite layer formed in situ on the perovskite active layer using n-hexyl trimethyl ammonium bromide.
• Poly(3-hexylthiophene) (P3HT) was employed as a dopant-free hole-transport material.
• Scalable bar-coating methods were used for fabricating large-area modules.

Main Results:

• A certified power conversion efficiency of 22.7% was achieved with minimal hysteresis (±0.51%).
• The devices demonstrated good stability, maintaining 95% of initial efficiency after 1,370 hours of operation under 1-Sun illumination at room temperature.
• Large-area modules (24.97 cm²) fabricated using scalable methods achieved a power conversion efficiency of 16.0%.

Conclusions:

• The proposed architecture successfully leverages P3HT as a dopant-free hole-transport material, significantly boosting perovskite solar cell efficiency and stability.
• This approach offers a promising pathway for the commercialization of perovskite solar cells by addressing cost and degradation issues associated with traditional materials.
• Utilizing a wide-bandgap halide in conjunction with P3HT presents a valuable research direction for advancing perovskite solar cell technology.