J. Electrochem. Sci. Technol., 2016, 7(3), 218-227 - 218 - Development of Macro-Porous Silicon Based Dye-Sensitized Solar Cells with Improved Light Trapping Mehdi Aliaghayee, Hassan Ghafoori Fard*, and Ashkan Zandi Department of Electrical Engineering, Amirkabir University of Technology, 424 Hafez Avenue,Tehran, 15875-4413, Iran ABSTRACT The light harvesting efficiency is counted as an important factor in the power conversion efficiency of DSSCs. There are two measures to improve this parameter, including enhancing the dye-loading capacity and increasing the light trapping in the photoanode structure. In this paper, these tasks are addressed by introducing a macro-porous silicon (PSi) substrate as photoanode. The effects of the novel photoanode structure on the DSSC performance have been investigated by using energy dispersive X-ray spectroscopy, photocurrent-voltage, UV-visible spectroscopy, reflectance spectroscopy, and elec- trochemical impedance spectroscopy measurements. The results indicated that bigger porosity percentage of the PSi struc- ture improved the both anti-reflective/light-trapping and dye-loading capacity properties. PSi based DSSCs own higher power conversion efficiency due to its remarkable higher photocurrent, open circuit voltage, and fill factor. Percent porosity of 64%, PSi(III), resulted in nearly 50 percent increment in power conversion efficiency compared with conventional DSSC. This paper showed that PSi can be a good candidate for the improvement of light harvesting efficiency in DSSCs. Furthermore, this study can be considered a valuable reference for more investigations in the design of multifunctional devices which will profit from integrated on-chip solar power. Keywords : Dye sensitized solar cell, Porous silicon, Electrochemical anodization, Light harvesting efficiency Received : 12 April 2016, Accepted : 7 August 2016 1. Introduction The light-harvesting efficiency (LHE) is one of the key features for high performance photovoltaic devices. This feature is derogated by reducing film thickness in thin-film solar cells such as dye sensi- tized solar cell (DSSC); therefore, many approaches are made to improve it. For example, porous active layer with high surface area [1-3], hierarchically nanostructures as photoanode [4-6], scattering layers on the top of active film [7-9], plasmonic photoan- odes [10-12] and photonic crystal photoanodes [13- 15] have been applied for changing the optical design of the DSSC to optimize its light absorbance. Since the mentioned approaches have some limitations like high reflectance loss and low dye adsorption, researchers are still extensively eager to explore the new light trapping structures as photoanode. Surface texturing is one of the most powerful tech- niques to improve thin film solar cell's efficiency. These textured substrates increase the LHE by: (a) reducing the probability of optical reflection of the front surface, (b) lengthening the optical path of the light through the cell, (c) trapping a greater percent- age of light within the thin active layers, and (d) increasing the electrode's surface area [16-18]. In the recent years some publications have reported the employing of surface textured substrates as photoan- ode for DSSCs, too. Reports of employing textured glass, patterned FTO, textured-3D TiO 2 active layer, and alternative grooved substrates like Ti metal as photoanode have resulted a significant increase in conversion effi- ciency. Hussain et al. reported the ICP-RIE textured glass substrate as photoanode. Their textured glass *E-mail address: ghafoorifard@aut.ac.ir DOI: http://dx.doi.org/10.5229/JECST.2016.7.3.218 Research Article Journal of Electrochemical Science and Technology