Organometal halide perovskites (OHPs) exhibit superior charge transport characteristics and ultralow thermal conductivities. However, thermoelectric (TE) applications of OHPs have been limited because of difficulties in controlling their carrier concentration, which is a key to optimizing their TE properties. Here, facile control of the carrier concentration in Sn-based OHPs is achieved by developing 2D crystal structures. The 2D OHP crystals are laterally oriented using a mixed solvent, and the morphology and crystal structure of the coexisting 2D/3D hybrid structures are systematically controlled via doping with methylammonium chloride. The effective number n_eff of inorganic octahedron layers in the 2D OHPs shows a strong positive correlation with the carrier concentration. Moreover, the 2D structure induces the quantum confinement effect, which enhances both the Seebeck coefficient and the electrical conductivity. A 2D OHP shows a high power factor of 111 µW m⁻¹ K⁻², which is an order of magnitude greater than the power factor of its 3D counterpart.

中文翻译：

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通过抑制 2D/3D 相分离提高 2D 有机金属卤化物钙钛矿的热电功率因数

有机金属卤化物钙钛矿 (OHP) 表现出优异的电荷传输特性和超低热导率。然而，OHP 的热电 (TE) 应用由于难以控制其载流子浓度而受到限制，这是优化其热电性能的关键。在这里，通过开发二维晶体结构可以轻松控制锡基 OHP 中的载流子浓度。2D OHP 晶体使用混合溶剂横向取向，并通过掺杂甲基氯化铵系统地控制共存的 2D/3D 混合结构的形态和晶体结构。有效数n _eff二维 OHP 中无机八面体层的数量与载流子浓度呈强正相关。此外，二维结构引起了量子限制效应，从而提高了塞贝克系数和电导率。2D OHP 显示出 111 µW m ^-1 K ^-2的高功率因数，这比其 3D 对应物的功率因数大一个数量级。