Improvement of quasi-2D perovskiet solar cells with dicyandiamide interface engineering
A research group led by professors Pengwei Li, Yanlin Song and Yiqiang Zhang has introduced a molecular bridge strategy based on Dicyandiamide (DCD) that significantly promotes quasi-2D alternating-kation interlayer (ACI) perovskite solar cells. Published in Nano-Micro letters, the study outlines a dual function interface engineering method that improves both efficiency and stability by passivating phase distribution and regulating phase distribution.
The team reported a recorder version efficiency of 21.54% for devices treated with DCD, compared to 19.05% in control monsters. DCD reduced the cross -border cross -border density by 73%, making it possible to charge charging transport and lower recombination percentages faster. Long -term tests showed treated devices that 94% of their initial efficiency retained after 1200 hours, which performed better than untreated cells that only maintained 84%.
The effectiveness of DCD stems from his guanidine and cyano groups. The guanidine group binds underwear PB2+ ions and fills iodide or cation evacatures, while the Cyano group coordinates with TI4+ in TIO2, which reduces oxygen vacancies and perovskiet/ETL interfaces are strengthened. DCD also suppressed low-n phase aggregation while promoting vertically aligned high-n phases, guaranteeing uniform load transport.
Spectroscopic and theoretical studies confirmed the mechanism. XPS and FTIR validated DCD interactions with PB and TI, while the oxygen vacancy evatios fell from 48% to 33%. Temporary absorption and photolumin rate studies revealed more homogeneous phase distributions and DFT calculations emphasized strong CN – Ti -binding, which explained the reduced falcon formation.
Performance tests showed a VOC of 1,172 V, JSC of 23.08 MA CM-2 and FF of 79.6%. The fall densities fell more than triple and the recombination resistance increased to 20.68 KO, which emphasized the efficient cargo extraction. The devices maintained stability under 400 hours of continuous lighting and 1200 hours combined thermal and environmental stress.
By integrating defective passivation with phase homogenization, this approach overcomes the traditional assessment of efficiency stability in 2D Perovoltaïschens. The team suggests that the strategy could extend to other perovskite-based opto electronics, including LEDs and photo detectors, which offers a universal platform for scalable, powerful device technology.
Research report:Dicyandiamide-driven customization of the N-value distribution and interface dynamics for powerful ACI 2D perovskiet solar cells
