Broadband Enhancement of PbS Quantum Dot Solar Cells by the Synergistic Effect of Plasmonic Gold Nanobipyramids and Nanospheres
Si Chen,1 Yongjie Wang,1 Qipeng Liu,1 Guozheng Shi,1 Zeke Liu,1 Kunyuan Lu,1 Lu Han,1Xufeng Ling,1 Han Zhang,2 Si Cheng,*2 and Wanli Ma*1
1Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM) Soochow University Suzhou, Jiangsu 215123, China
2College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, China
For the first time, the plasmonic gold bipyramids (Au BPs) are introduced to the PbS colloidal quantum dot (CQD) solar cells for improved infrared light harvesting. The localized surface plasmon resonance peaks of Au BPs matches perfectly with the absorption peaks of conventional PbS CQDs. Owing to the geometrical novelty of Au BPs, they exhibit significantly stronger far-fields cattering effect and near-field enhancement than conventional plasmonic Au nanospheres (NSs). Consequently, device open-circuit voltage (Voc) and short-circuit current (Jsc) are simultaneously enhanced, while plasmonic photovoltaic devices based on Au NSs only achieve improved Jsc. The different effects and working mechanisms of these two Au nanoparticles are systematically investigated. Moreover, to realize effective broadband light harvesting, Au BPs and Au NSs are used together to simultaneously enhance the device optical and electrical properties. As a result, a significantly increased power conversion efficiency (PCE) of 9.58% is obtained compared to the PCE of 8.09% for the control devices due to the synergistic effect of the two plasmonic Au nanoparticles. Thus, this work reveals the intriguing plasmonic effect of Au BPs in CQD solar cells and may provide insight into the future plasmonic enhancement for solution-processed new-generation solar cells.