Research Paper: Dicyandiamide‑Driven Tailoring of the n‑Value Distribution and Interface Dynamics for High‑Performance ACI 2D Perovskite Solar Cell
Summary
This study aims to address critical stability challenges and performance limitations, such as vertical phase segregation and buried interface defects, in quasi-2D alternating-cation-interlayer (ACI) perovskite solar cells (PSCs). The researchers introduced dicyandiamide (DCD) as a dual-functional modifier at the perovskite/TiO2 buried interface. Key findings demonstrate that DCD's guanidine group passivates undercoordinated Pb2+ and MA+ vacancies, while its cyano groups eliminate oxygen vacancies in TiO2, reducing interfacial trap density by 73%. DCD also regulates crystallization kinetics, suppressing low-n-phase aggregation and promoting beneficial vertical alignment of high-n phases, enhancing charge transport. This molecular bridge strategy resulted in optimised devices achieving a record power conversion efficiency (PCE) of 21.54% (compared to 19.05% for control devices) and significantly improved stability, retaining 94% of initial efficiency after 1200 hours under ambient conditions (versus 84% for unmodified counterparts).
Why it matters
These findings are crucial for advancing perovskite solar cell technology by providing an effective strategy to simultaneously enhance both efficiency and long-term stability, a significant trade-off in low-dimensional perovskites. The DCD-driven interface engineering offers a universal framework for developing high-performance optoelectronics by creating a more robust and efficient charge transport pathway and reducing degradation mechanisms, paving the way for more commercially viable and durable PSCs.
How Fluxim tools used
Fluxim’s PAIOS was employed to conduct transient photocurrent (TPC) and transient photovoltage (TPV) measurements. These measurements were vital for investigating charge transport and recombination dynamics between interfaces. The precise data obtained from PAIOS enabled the conclusion that the DCD-modified device exhibited a shorter charge extraction time and a longer recombination decay time, directly indicating faster carrier extraction and suppressed non-radiative recombination within the PSCs.
Publication Details
Chen, G., Gan, Y., Wang, S., Liu, X., Yang, J., Peng, S., Zhao, Y., Li, P., Komilov, A., Song, Y., Zhang, Y. (2025), Dicyandiamide‑Driven Tailoring of the n‑Value Distribution and Interface Dynamics for High‑Performance ACI 2D Perovskite Solar Cells. Nano-Micro Lett., 17:305. https://doi.org/10.1007/s40820-025-01817-x