Stable Plasmonic-Improved dye Sensitized Solar Cells by Silver Nanoparticles Between Titanium Dioxide Layers Omid Amiri a , Masoud Salavati-Niasari a, *, Mostafa Farangi b , Mehdi Mazaheri c, *, Samira Bagheri d a Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Iran b Thin Film Laboratory and Nano-Electronics, Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran c Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden d Centre for Research in Nanotechnology & Catalysis (NANOCAT), 3rd Floor, Block A, Institute of Postgraduate Studies (IPS) building, University of Malaya, Kuala Lumpur-50603, Malaysia A R T I C L E I N F O Article history: Received 1 November 2014 Received in revised form 16 November 2014 Accepted 17 November 2014 Available online 18 November 2014 Keywords: Nanoparticles Dye synthesized Solar cells Plasmonic A B S T R A C T Novel metal nanoparticles (NPs) are introduced as light-harvesting antennae to enhance photocurrent of photovoltaic cells. In this work, we examined the plasmonic enhancement of photocurrent in dye- sensitized solar cells with deposition of Ag NPs between different TiO 2 layers. The I–V measurement showed clearly that the open-circuit voltage (V OC ) of cells doesn't depend on Ag existence in our cells configuration extremely, however the short-circuit photocurrent density (J SC ) strongly depends on it. Deposition of Ag NPs on packing TiO 2 layer (T1) and transparent layer of TiO 2 (T2) both had acceptable results. The solar cells performance by treatment of Ag was studied and the results indicated that time treatment of AgNO 3 and KBH 4 is a key parameter which has effect on the PCE of the device. Low time (1 min), hardly shows any effect while medium time (2 min) shows significant effect on device performance. Meanwhile to improve the stability of these cells, we have proposed a new sealing method to fabricate promising stabile dye synthesized solar cells. ã 2014 Elsevier Ltd. All rights reserved. 1. Introduction Dye-sensitized solar cells (DSSCs) have received a great deal of scientific attraction and technical interest because of their easy- fabrication and low cost production. Although the development of new dyes has continued to improve the efficiency of DSSCs [1,2], but they are still limited by the weak absorption of the dye sensitizer. This is illustrated by the commonly used ruthenium (II) polypyridyl dyes (e.g., N719). N719 has sharply adsorption at 535 nm, but its extinction coefficients reduce drastically at longer wavelengths [3]. Thus, improving the light harvesting efficiency (LHE) in the 600  900 nm wavelength range is considered as a promising approach to increase the power conversion efficiency (PCE) and photocurrent of these devices [4,5]. Recently, it has been reported that Au and Ag NPs were used as light harvesting efficiency (LHE) factor [1,6–8]. Till now only a few methods of using Ag NPs have been tested in dye synthesized solar cells which include using Ag@SiO 2 [1], atomic layer deposition of Ag NPs [8] and drop casting of Ag [9]. Here we have introduced a new design to apply Ag in DSSCs by using three layers of TiO 2 in the cell and examining of the plasmonic enhancement of dye- sensitized photocurrent with deposition of Ag NPs between TiO 2 layers. The chemical treatment has been carried out using titanium tetrachloride (TiCl 4 ). The electrical conductivity has been im- proved at the interfaces of particles in the TiO 2 coating and between conducting glass and the TiO 2 film (T1) through TiCl 4 treatment [10,11]. Also post-treated was used to improve the quality of surface [10,11]. The cell performance of dye-synthesized solar cells was investigated as Ag was deposited between the layers and FTO/T1/Ag/T2/Ag/T3 device showed the best result. The distance between the novel nano-metal particles and the dye has shown a significant effect on photocurrent in DSSCs. By exciting electrons of N719 molecules, localized electric fields of plasmonic NPs can increase the photocurrent more efficiently compered to incident far field light. We also obtained optimized amount of Ag in these layers. Stability is another problem of Dye synthesized solar cell. Typical dye-sensitized solar cells suffer from durability problems because of their usage of organic liquid electrolytes containing the iodide/tri-iodide redox couple, which causes serious problems * Corresponding author. Tel.: +0098 31 55912383. E-mail address: salavati@kashanu.ac.ir (M. Salavati-Niasari). http://dx.doi.org/10.1016/j.electacta.2014.11.105 0013-4686/ ã 2014 Elsevier Ltd. All rights reserved. Electrochimica Acta 152 (2015) 101–107 Contents lists available at ScienceDirect Electrochimica Acta journa l home page : www.e lsevier.com/loca te/ele cta cta