Tin halide perovskites are promising lead-free candidates for light-emitting diodes (LEDs), but their performance is hindered by the poor crystallinity quality and the oxidation of tin. It is necessary but challenging to simultaneously realize modulating crystallization, suppressing oxidation, and passivating defects to boost the device’s performance. Here, naphthol sulfonic salt is demonstrated as an effective multifunctional additive. The sulfonic group can retard crystallization by forming intermediate complexes with perovskite to form a pinhole-free film. The reducing hydroxyl group can prevent Sn²⁺ from oxidation and hinder the migration of I^– ions. The high electron density of the naphthol ring can enhance the electrostatic attraction toward undercoordinated Sn²⁺ to passivate the defects. The synergistic effect of the multifunctional additive contributes to a boosted efficiency of 0.72% and a brightness of 132 cd m^–2 for quantum-well structure phenethylammonium tin iodide ((PEA)₂SnI₄) LEDs, which represents the most effective lead-free perovskite LEDs in pure-red regions as far as we know.

中文翻译：

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多功能萘酚磺酸盐掺入无铅二维卤化钙钛矿中，用于红色发光二极管

卤化钙钛矿是有前途的无铅发光​​二极管（LED）候选物，但其性能因结晶性差和锡的氧化而受到阻碍。同时实现调制结晶，抑制氧化和钝化缺陷以提高器件性能是必要但具有挑战性的。在这里，萘酚磺酸盐被证明是一种有效的多功能添加剂。磺酸基团可以通过与钙钛矿形成中间配合物来形成无针孔膜，从而延迟结晶。还原羟基可以防止的Sn ²⁺氧化和阻碍的我迁移^-离子。萘酚环的高电子密度可增强对配位不足的Sn ²⁺的静电吸引钝化缺陷。多功能添加剂的协同效应有助于将量子阱结构的苯乙碘化锡（PEA）₂ SnI ₄）LED的效率提高0.72％，亮度达到132 cd m ^–2，这是最有效的无铅LED据我们所知，纯红色区域中的钙钛矿型LED。