Controlling Surface Chemistry in Tin-Lead Perovskites for High-Efficiency Solar Cells
Abstract
Interfacial nonradiative recombination limits tin-lead perovskite photovoltaics. Here we show that neutral ethylenediamine chelates undercoordinated metals at tin-rich surfaces, weakens metal-iodide bonds, and removes excess tin, reconstructing the surface towards a stoichiometric tin-to-lead ratio. In contrast, protonated ethylenediammonium iodide initially passivates undercoordinated metal sites before undergoing defect-assisted deprotonation. Atomistic simulations reveal that subsurface iodide vacancies promote iodide migration and lower the energetic cost of deprotonation. Ethylenediamine-induced reconstruction produces stronger n-type surface character, facilitates electron extraction into C60, and suppresses interfacial nonradiative recombination, enabling methylammonium-free solar cells with a power conversion efficiency of 25.86%. Together, these distinct surface reaction pathways and the defect-assisted evolution of the passivating species underscore the importance of understanding perovskite surface chemistry for the rational design of molecular passivation strategies.
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BibTeX
@misc{chen2026controlling,
title = {{Controlling Surface Chemistry in Tin-Lead Perovskites for High-Efficiency Solar Cells}},
author = {Lijun Chen and Sitong Zhao and Gaukhar Nigmetova and David Garcia Romero and Matteo Pitaro and Sofia Lerda and Edoardo Mosconi and Michael Aidi and Douwe van Netten and Julia Kraft and Jiaxiong Li and Jacopo Pinna and Asya Serafimova and Antonija Grubišić-Čabo and Loredana Protesescu and Giuseppe Portale and Petra Rudolf and Filippo De Angelis and Maria Antonietta Loi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34293},
eprint = {2610.34293},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34293},
}
RIS
TY - UNPB
TI - Controlling Surface Chemistry in Tin-Lead Perovskites for High-Efficiency Solar Cells
AU - Lijun Chen
AU - Sitong Zhao
AU - Gaukhar Nigmetova
AU - David Garcia Romero
AU - Matteo Pitaro
AU - Sofia Lerda
AU - Edoardo Mosconi
AU - Michael Aidi
AU - Douwe van Netten
AU - Julia Kraft
AU - Jiaxiong Li
AU - Jacopo Pinna
AU - Asya Serafimova
AU - Antonija Grubišić-Čabo
AU - Loredana Protesescu
AU - Giuseppe Portale
AU - Petra Rudolf
AU - Filippo De Angelis
AU - Maria Antonietta Loi
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2610.34293
UR - https://arxiv.org/abs/2610.34293
AB - Interfacial nonradiative recombination limits tin-lead perovskite photovoltaics. Here we show that neutral ethylenediamine chelates undercoordinated metals at tin-rich surfaces, weakens metal-iodide bonds, and removes excess tin, reconstructing the surface towards a stoichiometric tin-to-lead ratio. In contrast, protonated ethylenediammonium iodide initially passivates undercoordinated metal sites before undergoing defect-assisted deprotonation. Atomistic simulations reveal that subsurface iodide vacancies promote iodide migration and lower the energetic cost of deprotonation. Ethylenediamine-induced reconstruction produces stronger n-type surface character, facilitates electron extraction into C60, and suppresses interfacial nonradiative recombination, enabling methylammonium-free solar cells with a power conversion efficiency of 25.86%. Together, these distinct surface reaction pathways and the defect-assisted evolution of the passivating species underscore the importance of understanding perovskite surface chemistry for the rational design of molecular passivation strategies.
ER -