Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology (HUST) , 1037 Luoyu Road, 430074 Wuhan, Hubei, P.R. China.
ACS Nano. 2017 Sep 26;11(9):9294-9302. doi: 10.1021/acsnano.7b04683. Epub 2017 Sep 11.
Colloidal quantum dots (QDs) of lead halide perovskite have recently received great attention owing to their remarkable performances in optoelectronic applications. However, their wide applications are hindered from toxic lead element, which is not environment- and consumer-friendly. Herein, we utilized heterovalent substitution of divalent lead (Pb) with trivalent antimony (Sb) to synthesize stable and brightly luminescent CsSbBr QDs. The lead-free, full-inorganic QDs were fabricated by a modified ligand-assisted reprecipitation strategy. A photoluminescence quantum yield (PLQY) was determined to be 46% at 410 nm, which was superior to that of other reported halide perovskite QDs. The PL enhancement mechanism was unraveled by surface composition derived quantum-well band structure and their large exciton binding energy. The Br-rich surface and the observed 530 meV exciton binding energy were proposed to guarantee the efficient radiative recombination. In addition, we can also tune the inorganic perovskite QD (CsSbX) emission wavelength from 370 to 560 nm via anion exchange reactions. The developed full-inorganic lead-free Sb-perovskite QDs with high PLQY and stable emission promise great potential for efficient emission candidates.
卤化铅钙钛矿胶体量子点由于其在光电应用中的卓越性能而受到了极大的关注。然而，由于其中含有有毒的铅元素，它们的广泛应用受到了阻碍，这对环境和消费者都不友好。在此，我们利用二价铅（Pb）与三价锑（Sb）的杂价取代来合成稳定且发光亮度高的 CsSbBr 量子点。无铅、全无机量子点是通过改良的配体辅助再沉淀策略制备的。在 410nm 处的光致发光量子产率（PLQY）被确定为 46%，优于其他报道的卤化铅钙钛矿量子点。通过表面组成衍生的量子阱能带结构和大的激子结合能揭示了 PL 增强机制。富 Br 的表面和观察到的 530meV 的激子结合能被认为是保证高效辐射复合的原因。此外，我们还可以通过阴离子交换反应将无机钙钛矿量子点（CsSbX）的发射波长从 370nm 调谐到 560nm。所开发的具有高光致发光量子产率和稳定发射的全无机无铅 Sb 钙钛矿量子点有望成为高效发光候选材料。
