Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
Nat Commun. 2013;4:2004. doi: 10.1038/ncomms3004.
There has been much controversy over the incorporation of organic-ligand-encapsulated plasmonic nanoparticles in the active layer of bulk heterojunction organic solar cells, where both enhancement and detraction in performance have been reported. Here through comprehensive transient optical spectroscopy and electrical characterization, we demonstrate evidence of traps responsible for performance degradation in plasmonic organic solar cells fabricated with oleylamine-capped silver nanoparticles blended in the poly (3-hexylthiophene):[6,6]-phenyl-C 61-butyric acid methyl ester active layer. Despite an initial increase in exciton generation promoted by the presence of silver nanoparticles, transient absorption spectroscopy reveals no increase in the later free polaron population-attributed to fast trapping of polarons by nearby nanoparticles. The increased trap-assisted recombination is also reconfirmed by light intensity-dependent electrical measurements. These new insights into the photophysics and charge dynamics of plasmonic organic solar cells would resolve the existing controversy and provide clear guidelines for device design and fabrication.
在体异质结有机太阳能电池的活性层中加入有机配体包裹的等离子体纳米粒子引起了很多争议，有报道称其性能既有增强也有降低。在这里，我们通过综合瞬态光学光谱和电学特性研究，证明了在以油酸胺封端的银纳米粒子与聚（3-己基噻吩）：[6,6]-苯基-C61-丁酸甲酯活性层共混的等离子体有机太阳能电池中，存在导致性能下降的陷阱。尽管存在银纳米粒子会促进激子生成，但瞬态吸收光谱显示，自由极化子的数量并没有增加，这归因于附近纳米粒子的快速极化子捕获。光强依赖的电测量也再次证实了增加的陷阱辅助复合。这些对等离子体有机太阳能电池的光物理和电荷动力学的新见解将解决现有的争议，并为器件设计和制造提供明确的指导。
