Singlet Fission and Triplet Transfer to PbS Quantum Dots in TIPS-Tetracene Carboxylic Acid Ligands
Singlet Fission and Triplet Transfer to PbS Quantum Dots in TIPS-Tetracene Carboxylic Acid Ligands
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DOI：
10.1021/acs.jpclett.8b00099
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发表时间：
2018-03-15
影响因子：
5.7
通讯作者：
Rao, Akshay
中科院分区：
文献类型：
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作者：
Davis, Nathaniel J. L. K.;Allardice, Jesse R.;Rao, Akshay
单线态激子裂变允许对于在有机半导体内吸收的每个光子产生两个三线态激子。这些三重态的有效收获可以允许打破单结光致发光器件的功率转换效率的肖克利-奎塞尔限制。在这里，我们表明，单线态裂变分子直接绑定到PbS量子点作为配体可以进行单线态裂变与近单位效率，并可以转移三重态顺序到PbS与近单位效率。在PbS中，激发复合，产生光子发射。这允许当光子被单线态裂变配体吸收时，与直接吸收在量子点中时相比，量子点光致发光量子效率加倍。我们的方法证明了将单重态裂变的激子倍增过程转化为光子倍增过程的可能性，为利用光子学来控制单重态裂变提供了一条新的途径。
Singlet exciton fission allows for the generation of two triplet excitons for each photon absorbed within an organic semiconductor. Efficient harvesting of these triplets could allow for the Shockley-Queisser limit on the power conversion efficiency of single-junction photovoltaics to be broken. Here, we show that singlet fission molecules bound directly to PbS quantum dots as ligands can undergo singlet fission with near unity efficiency and can transfer triplets sequentially into the PbS with near unity efficiency. Within the PbS, the excitations recombine, giving rise of the emission of photons. This allows for the doubling of the quantum dot photoluminescence quantum efficiency when photons are absorbed by the singlet fission ligand, as compared to when directly absorbed in the quantum dot. Our approach demonstrates that it is possible to convert the exciton multiplication process of singlet fission into a photon multiplication process and provides a new path to harness singlet fission with photovoltaics.