title: Performance Improvement of Polymer Solar Cells by Surface-Energy-Induced Dual Plasmon Resonance.
abstract: The surface plasmon resonance (SPR) effect of metal nanoparticles (MNPs) is effectively applied on polymer solar cells (PSCs) to improve power conversion efficiency (PCE). However, universality of the reported results mainly focused on utilizing single type of MNPs to enhance light absorption only in specific narrow wavelength range. Herein, a surface-energy-induced dual MNP plasmon resonance by thermally evaporating method was presented to achieve the absorption enhancement in wider range. The differences of surface energy between silver (Ag), gold (Au), and tungsten trioxide (WO3) compared by contact angle images enable Ag and Au prefer to respectively aggregate into isolated islands rather than films at the initial stage of the evaporation process, which was clearly demonstrated in the atomic force microscopy (AFM) measurement. The sum of plasmon-enhanced wavelength range induced by both Ag NPs (350-450 nm) and Au NPs (450-600 nm) almost cover the whole absorption spectra of active layers, which compatibly contribute a significant efficiency improvement from 4.57 ± 0.16 to 6.55 ± 0.12% compared to the one without MNPs. Besides, steady state photoluminescence (PL) measurements provide strong evidence that the SPR induced by the Ag-Au NPs increase the intensity of light absorption. Finally, ultraviolet photoelectron spectroscopy (UPS) reveals that doping Au and Ag causes upper shift of both the work function and valence band of WO3, which is directly related to hole collection ability. We believe the surface-energy-induced dual plasmon resonance enhancement by simple thermally evaporating technique might pave the way toward higher-efficiency PSCs.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , 2699 Qianjin Street, Changchun 130012, People's Republic of China.
authors.forename: Mengnan
authors.initials: M
authors.lastname: Yao
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , 2699 Qianjin Street, Changchun 130012, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Shen
authors.affiliation: Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University , Changchun 130022, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , 2699 Qianjin Street, Changchun 130012, People's Republic of China.
authors.forename: Boyuan
authors.initials: B
authors.lastname: Chen
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , 2699 Qianjin Street, Changchun 130012, People's Republic of China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Guo
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , 2699 Qianjin Street, Changchun 130012, People's Republic of China.
authors.forename: Shengping
authors.initials: S
authors.lastname: Ruan
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , 2699 Qianjin Street, Changchun 130012, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
keywords: buffer layer; metal nanoparticles; photoluminescence; plasmon resonance; polymer solar cells; surface energy