Speed Limit for Triplet-Exciton Transfer in Solid-State PbS Nanocrystal-Sensitized Photon Upconversion
Speed Limit for Triplet-Exciton Transfer in Solid-State PbS Nanocrystal-Sensitized Photon Upconversion
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DOI：
10.1021/acsnano.7b02024
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发表时间：
2017-08-01
期刊：
影响因子：
17.1
通讯作者：
Bawendi, Moungi G.
中科院分区：
文献类型：
--
作者：
Nienhaus, Lea;Wu, Mengfei;Bawendi, Moungi G.
将无机和有机材料结合在一起的混合界面支撑了许多光电子和光催化系统的运行，并允许采用创新的方法进行光子上转换和下转换。然而，自旋三重态激子通过这些界面交换介导的能量转移的机制仍然不清楚，特别是当宏观施主和受主都由许多单独相互作用的纳米部分组成的时候。在这里，我们研究了激子从胶体硫化铅(PbS)纳米晶到Rubrene分子的自旋三重态的转移。通过将纳米晶表面的羧酸配体的长度从18个碳原子减少到4个碳原子，将有效的配体壳层从13埃变薄到6埃，我们能够将特征转移速率提高一个数量级。然而，我们观察到较短分离距离的能量传递速率渐近线(
Hybrid interfaces combining inorganic and organic materials underpin the operation of many optoelectronic and photocatalytic systems and allow for innovative approaches to photon up- and down-conversion. However, the mechanism of exchange-mediated energy transfer of spin-triplet excitons across these interfaces remains obscure, particularly when both the macroscopic donor and acceptor are composed of many separately interacting nanoscopic moieties. Here, we study the transfer of excitons from colloidal lead sulfide (PbS) nanocrystals to the spin-triplet state of rubrene molecules. By reducing the length of the carboxylic acid ligands on the nanocrystal surface from 18 to 4 carbon atoms, thinning the effective ligand shell from 13 to 6 angstrom, we are able to increase the characteristic transfer rate by an order of magnitude. However, we observe that the energy transfer rate asymptotes for shorter separation distances (