Tailored Polymer Hole-Transporting Materials with Multisite Passivation Functions for Effective Buried-Interface...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Quasi-2D Ruddlesden-Popper (RP) perovskites offer improved stability but lag behind 3D counterparts in photovoltaic performance.
• Optimizing buried interfaces and reducing energy losses are key to enhancing efficiency and stability in inverted quasi-2D RP perovskite solar cells (PSCs).
• Developing polymer hole-transporting materials (HTMs) with defect passivation capabilities is crucial for buried-interface engineering in these devices.

Purpose of the Study:

• To design and synthesize novel polymer HTMs for improved buried-interface engineering in inverted quasi-2D RP PSCs.
• To enhance charge extraction, defect passivation, and perovskite crystallization through tailored HTM side-chain functionality.
• To achieve high power conversion efficiency (PCE) and stability in quasi-2D RP PSCs.

Main Methods:

• Side-chain tailoring strategy was employed to modify π-conjugation and functionality of polymer HTMs.
• Synthesized PVCz-ThSMeTPA and PVCz-ThOMeTPA polymers with high hole mobility and multisite passivation functions.
• Investigated the impact of sulfur atom-containing groups on intermolecular interactions, energy levels, and interfacial properties.

Main Results:

• Achieved high hole mobility of 9.20 × 10^-4 cm² V^-1 S^-1 for PVCz-ThSMeTPA.
• Demonstrated that PVCz-ThSMeTPA enhances intra/intermolecular interactions, optimizes energy levels, and improves interfacial contact with perovskite.
• The PVCz-ThSMeTPA-based inverted quasi-2D PSC achieved a champion PCE of 22.37%.

Conclusions:

• Multifunctional polymer HTMs with tailored side-chains are effective for buried-interface engineering in quasi-2D PSCs.
• PVCz-ThSMeTPA enables efficient charge extraction, defect passivation, and improved perovskite crystallization.
• The developed HTM represents a significant advancement, achieving one of the highest PCEs reported for quasi-2D RP PSCs.