Dielectrically Confined Stable Excitons in Few-Atom-Thick PbS Nanosheets
Dielectrically Confined Stable Excitons in Few-Atom-Thick PbS Nanosheets
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少原子厚的 PbS 纳米片中的介电约束稳定激子
DOI：
10.1021/acs.jpclett.2c02254
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Sun, Liangfeng
中科院分区：
文献类型：
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作者：
Weeraddana, Tharaka MDS;Premathilaka, Shashini M.;Tang, Yiteng;Antu, Antara Debnath;Roach, Adam;Yang, Jun;Sun, Liangfeng
二维胶体PbS纳米片表现出比它们的本体对应物大一个数量级以上的激子结合能，使得有可能在室温下产生稳定的激子。实验表明，随着PbS纳米片厚度从4.7 nm减小到1.2 nm，激子的结合能从26 meV增加到68 meV。激子的电介质限制在结合能增强中起着关键作用。实验证实，大的结合能导致快速的厚度依赖性激子辐射复合速率。
Two-dimensional colloidal PbS nanosheets exhibit more than one order of magnitude larger exciton binding energy than their bulk counterpart, making it possible to generate stable excitons at room temperature. It is experimentally revealed that the binding energy of the exciton increases from 26 to 68 meV as the thickness of the PbS nanosheet decreases from 4.7 to 1.2 nm. The dielectric confinement of the exciton plays a critical role in the binding-energy enhancement. The large binding energy results in a fast thickness-dependent exciton radiative recombination rate, confirmed experimentally.