Morphological consequences of ligand exchange in quantum dot - Polymer solar cells
Morphological consequences of ligand exchange in quantum dot - Polymer solar cells
复制标题
DOI：
10.1016/j.orgel.2017.12.018
复制
发表时间：
2018-03
影响因子：
3.2
通讯作者：
Raymond T. Hickey;Erin Jedlicka;B. Pokuri;Adam E Colbert;Z. I. Bedolla-Valdez;B. Ganapathysubramanian
中科院分区：
文献类型：
--
作者：
Raymond T. Hickey;Erin Jedlicka;B. Pokuri;Adam E Colbert;Z. I. Bedolla-Valdez;B. Ganapathysubramanian
共轭聚合物和量子点纳米晶体的混合物为光电子器件（包括太阳能电池）的有源层提供了一个有趣的溶液可加工材料系统。我们利用扫描透射电子显微镜研究了交换量子点的盖层配体对薄膜三维形貌的影响。我们创建了聚(（4,8-双（辛氧基）苯并（1,2-b:4,5-b ')-二噻吩-2,6-二基）（2-（十二烷基氧基）羰基）噻吩(3,4-b)-噻吩二基）（PTB1）和PbS量子点的三维重建，这些量子点被油酸（OA）、丁胺（BA）、OA到3-巯基丙酸（MPA）和BA到MPA覆盖。我们使用这些重建的体积来评估激子解离和电荷传输作为配体处理的函数的差异。我们发现，没有中间BA处理的MPA交换会导致膜结构的严重变化和有效装置的非理想形态。我们还发现，在BA交换的情况下，形貌与额外的MPA处理基本保持不变。这种定量表征阐明了先前报道的由配体交换引起的器件性能变化，并应告知未来的器件制造方案。
Mixtures of conjugated polymers and quantum dot nanocrystals present an interesting solution-processable materials system for active layers in optoelectronic devices, including solar cells. We use scanning transmission electron microscopy to investigate the effects of exchanging the capping ligand of quantum dots on the three-dimensional morphology of the film. We created 3D reconstructions for blends of poly((4,8-bis(octyloxy)benzo(1,2-b:4,5-b’)-dithiophene-2,6-diyl)(2-((dodecyloxy)carbonyl)thieno (3,4-b)-thiophenediyl)) (PTB1) and PbS quantum dots capped with oleic acid (OA), butylamine (BA), OA to 3-mercaptopropionic acid (MPA), and BA to MPA. We use these reconstructed volumes to evaluate differences in exciton dissociation and charge transport as a function of ligand processing. We show that the MPA exchange without an intermediate BA treatment results in severe changes to the film structure and a non-ideal morphology for an effective device. We also show that with a BA exchange, the morphology remains largely unchanged with the additional MPA treatment. This quantitative characterization elucidates previously reported device performance changes caused by ligand exchange and should inform future device fabrication protocols.