Solution-processed hybrid organic–inorganic perovskites (HOIPs) from organoammonium halide and lead halide precursors form efficacious active layers for photovoltaics, light-emitting diodes, and flexible electronics. Though solvent–solute coordination plays a critical role in HOIP crystallization, the influence of solvent choice on such interactions is poorly understood. We demonstrate Gutmann’s donor number, D_N, as a parameter that indicates the coordinating ability of the processing solvent with the Pb²⁺ center of the lead halide precursor. Low D_N solvents interact weakly with the Pb²⁺ center, favoring instead complexation between Pb²⁺ and iodide and subsequent crystallization of perovskite. High D_N solvents coordinate more strongly with the Pb²⁺ center, which in turn inhibits iodide coordination and stalls perovskite crystallization. Varying the concentration of high-D_N additives in precursor solutions tunes the strength of lead–solvent interactions, allowing finer control over the crystallization and the resulting morphology of HOIP active layers.

中文翻译：

---

溶剂配位对有机-无机钙钛矿杂化形成的影响

由有机卤化铵和卤化铅前驱体进行溶液处理的有机-无机钙钛矿杂化物（HOIP）形成了光伏，发光二极管和柔性电子产品的有效活性层。尽管溶剂与溶质的配位在HOIP结晶中起着关键作用，但对于这种相互作用的溶剂选择的影响知之甚少。我们证明了古特曼的供体数D _N作为参数，该参数指示加工溶剂与卤化铅前体的Pb ²⁺中心的配位能力。低D _N溶剂与Pb ²⁺中心的相互作用较弱，从而有利于Pb ²⁺之间的络合碘化物和钙钛矿的后续结晶。高D _N溶剂与Pb ²⁺中心的配位作用更强，进而抑制了碘化物的配位并阻止了钙钛矿的结晶。通过改变前驱体溶液中高D _N添加剂的浓度，可以调节铅与溶剂之间的相互作用强度，从而可以更好地控制HOIP活性层的结晶和所形成的形态。