POS10-1465
Computational Insights into p-Type Doping and Sn2+ Protection by Bifunctional Polymer in Tin–Lead Perovskites
Topic
S10. AI-assisted Design and Simulation of Polymers
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Sang Wook Park (Hanyang University)
Co-Author(s)
Abstract
Although tin–lead perovskites (TLPs) are attractive narrow-bandgap absorbers for high-efficiency solar cells, their device performance and long-term stability remain constrained by spontaneous Sn2+ oxidation and inefficient charge transport. Sn2+ oxidation promotes Sn-vacancy formation and uncontrolled self-p-type doping, which compromise device stability through oxidation-induced p-type behavior. Controlled p-type doping is therefore essential for improving hole extraction and valence-band alignment without inducing additional Sn oxidation. In this work, we introduce poly(pyrrolidinium-Jeffamine) hexafluorophosphate (PPJ-PF6) as a bifunctional copolymer additive that enables controlled p-type doping while protecting oxidation-sensitive Sn2+ sites. Density functional theory (DFT) calculations elucidated the molecular function of PPJ-PF6. The favorable electrostatic interaction between the pyrrolidinium cation and PF6- anion resulted in a strong ion-pair binding energy of approximately −3.8 eV, indicating that PF6- is effectively anchored within the pyrrolidinium-based polymer framework. Slab calculations showed favorable PPJ-PF₆ adsorption on the TLP surface, where the pyrrolidinium–PF6 unit interacts with uncoordinated metal sites to promote controlled p-type doping, while the Jeffamine segment coordinates Sn2+ through ether oxygen atoms to enhance Sn2+ protection and interfacial stability. Additional DFT analysis showed that PF6− incorporation at representative Sn and Pb sites induces a downward Fermi-level shift and increases the work function, indicating controlled p-type doping through surface charge redistribution rather than Sn2+ oxidation. Supported by the computational results, PPJ-PF6 suppresses trap-assisted recombination and enhances hole transport, enabling a champion PCE of 22.8% and improved operational stability. This work presents a bifunctional polymer strategy for oxidation-safe p-type doping in TLP solar cells.
