Molecular Dipole Buffer Layer Enabling Compact Interfaces in Perovskite Solar Cells
Despite advances in p-i-n perovskite solar cells, interfacial losses between the electron transport layer (ETL) and metal electrode remain a bottleneck for efficiency and stability. Bathocuproine (BCP), a common buffer layer, suffers from poor film uniformity, low electron mobility, and limited thermal stability. Here, we report BTI-N, a D-A-D-type small molecule featuring a benzo-[c]-[1,2,5]-thiadiazole core and polar N,N-dimethylamino groups. BTI-N exhibits favorable molecular packing and solubility, enabling compact, uniform films with efficient electron transport. The polar termini anchor Ag electrodes via Ag-N dipole formation, lowering the work function and improving band alignment and charge extraction. BTI-N also suppresses Ag and I ion diffusion, significantly enhancing thermal stability. We demonstrate broad compatibility across ETLs (C<sub>60</sub>, PCBM), electrodes (Ag, Au), and perovskites with bandgaps from 1.58 to 1.7 eV. This work provides a practical interface engineering strategy to replace BCP and realize high-performance, stable perovskite solar cells.
Authors
- Weidong Xu (ORCID: https://orcid.org/0000-0002-3934-8579)
- Chieh‐Szu Huang (ORCID: https://orcid.org/0000-0002-2654-8352)
- Yoomi Ahn (ORCID: https://orcid.org/0009-0003-3689-5141)
- Eunhye Yang
- Danbi Kim (ORCID: https://orcid.org/0000-0002-5432-8613)
- Sung Heum Park (ORCID: https://orcid.org/0000-0001-5701-660X)
- Samuel D. Stranks (ORCID: https://orcid.org/0000-0002-8303-7292)
- Eui Dae Jung (ORCID: https://orcid.org/0000-0003-4848-0931)
- Bo Ram Lee (ORCID: https://orcid.org/0000-0002-4670-6717)
- L. Meng (ORCID: https://orcid.org/0000-0002-2901-6589)
- Hongsuk Suh
- Yang Lu (ORCID: https://orcid.org/0000-0002-2793-2065)
Institutions
- National University of Singapore (SG)
- University of Cambridge (GB)
- Université Bourgogne Franche-Comté (FR)
- Pusan National University (KR)
- Sungkyunkwan University (KR)
- Pukyong National University (KR)
Publication Details
- Journal
- ACS Energy Letters
- Published
- 2025-09-03
- DOI
- https://doi.org/10.1021/acsenergylett.5c02004
- Citations
- 2
- Primary Topic
- Perovskite Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 1.46
Funders
- Royal Society
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Sungkyunkwan University
- Korea Research Institute of Chemical Technology
- National Research Foundation of Korea
- Tata Sons
- Samsung
- Engineering and Physical Sciences Research Council