Enhanced Quasi-Fermi Level Splitting of Perovskite Solar Cells by Universal Dual-Functional Polymer

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) show high power conversion efficiency (PCE) and simple fabrication.
• Open-circuit voltage (VOC) loss hinders PSC performance enhancement.

Purpose of the Study:

• To introduce a universal multifunctional polymer additive to boost VOC in PSCs.
• To overcome VOC loss limitations and approach the Shockley-Queisser (S-Q) limit.

Main Methods:

• A facile strategy using a multifunctional polymer additive was employed.
• The additive passivates both cation and anion defects in perovskite films.
• Energy level alignment and suppression of non-radiative recombination were investigated.

Main Results:

• The polymer additive boosted VOC to 95.5% of the S-Q limit.
• Champion devices achieved a VOC of 1.24 V and PCE of 23.86% (1.59 eV perovskite).
• A PCE of 25.04% was reached for 1.57 eV PSCs, and a 14 cm² module achieved 21.95% PCE.

Conclusions:

• The strategy effectively passivates defects, enhancing quasi-Fermi level splitting (QFLS).
• This universal approach significantly improves VOC across various perovskite systems.
• The method provides a pathway to achieve theoretical efficiency limits in PSCs.