State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, P. R. China.
University of the Chinese Academy of Sciences, Beijing, 100039, P. R. China.
Angew Chem Int Ed Engl. 2017 Oct 2;56(41):12471-12475. doi: 10.1002/anie.201704739. Epub 2017 Aug 30.
Lead-based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead-based and the other is the poor stability. Lead-free all-inorganic perovskite Cs Bi X (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand-free Cs Bi Br NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2 %. The PLQE can be increased to 4.5 % when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2-20 ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30 days.
含铅钙钛矿纳米晶体（NCs）具有出色的光学性能和廉价的合成方法，这使其在光电设备领域具有巨大的潜力。然而，两个关键问题仍未得到解决，这阻碍了它们的商业应用：一个是含铅的事实，另一个是稳定性差。通过简便的室温反应，合成了发射波长范围为 400 至 560nm 的无配体的全无机钙钛矿 Cs Bi X（X=Cl、Br、I）NCs。无配体的 Cs Bi Br NCs 具有蓝色发射，光致发光量子效率（PLQE）约为 0.2%。当在合成过程中添加额外的表面活性剂（油酸）时，PLQE 可以增加到 4.5%。这种改进源于快速捕获过程（2-20ps）的钝化。值得注意的是，在潮湿条件下也可以钝化陷光态，并且 NCs 在超过 30 天的时间内对空气暴露表现出高稳定性。
