Periodically arranged colloidal gold nanoparticles for enhanced light harvesting in organic solar cells

Mina Mirsafaei, André Luis Fernandes Cauduro, Casper Kunstmann-Olsen, Adam Michael Davidson, Søren Hassing, Martin A.B. Hedegaard, Horst-Günter Rubahn, Jost Adam, Morten Madsen

Research output: Contribution to conference without publisher/journalPosterResearchpeer-review


The photovoltaic (PV) market is currently dominated by silicon solar cells, mainly due to their high power conversion efficiency. They are, however, cost inefficient, which has led to the development of solar cells based on organic semiconductors. The ease of processing organic materials, the low material and fabrication costs along with the possibility of making ultra-thin and flexible devices makes organic solar cells ideal candidates as efficient components on a future renewable energy market. Over the past ten years, investigations on the synthesis of new organic semiconductors, on morphological optimizations and on new device structures have led to improved organic solar cell performances. Nevertheless, organic solar cells still show relatively low power conversion efficiencies, mainly due to inherent drawbacks such as short exciton diffusion lengths and low carrier mobility in the organic active layer. The resulting loss mechanisms lead to hampered device performances, especially for optically thick devices. One of the approaches to improve the device performance is increasing the light absorption in the active layer, for example by using nano- or micro-structures that diffract light at specific wavelengths into large angles in the active layers1, or by using the localized surface plasmon resonance (LSPR) effect of metal nanoparticles (MNPs)2. The use of such lighttrapping mechanisms also makes it possible to improve charge extraction, as it allows for the fabrication of thinner devices without compromising light absorption. In this work, we theoretically and experimentally investigate periodically arranged colloidal gold nanoparticles in organic solar cells, and demonstrate the use of such nanostructures to improve the light absorption in and thus the efficiency of organic solar cells. We theoretically study the optical interference and absorption in multilayer stacks via numerical analysis based on finite-difference time-domain (FDTD) and transfer matrix method (TMM). Based on our model, we perform parametric studies of the influence of the size of the plasmonic nanostructures as well as the period of the periodical arrangements in organic bulk hetero-junction solar cells. In addition, we investigate experimentally the light absorption enhancement in the organic active layer by incorporating surface-ordered gold nanoparticle arrangements at the bottom of the organic active layer. The latter are fabricated with a lithography-free stamp technique, creating a centimeter scaled area with defined inter-particle spacing. Our study presents the light harvesting ability of template-assisted nanoparticle assemblies in organic solar cells and as the approach is easily scalable, it also demonstrates an efficient method for developing large-scale, low cost devices. Moreover, as the presented method is easily transferable to other platforms, it can be applied to various future device applications.
Original languageEnglish
Publication date6. Apr 2016
Publication statusPublished - 6. Apr 2016
EventSPIE PHOTONICS EUROPE 2016 - Brussels, Belgium
Duration: 4. Apr 20167. Apr 2016


Internet address

Bibliographical note

[1] Roana Melina de Oliveira Hansen; Liu Yinghui; Madsen Morten; Horst-Günter Rubahn, "Flexible
organic solar cells including efficiency enhancing grating structures". Nanotechnology, 24 (14),145301 (2013).
[2]Christoph Hanske; Moritz Tebbe; Christian Kuttner; Vera Bieber; Vladimir V. Tsukruk; Munish Chanana; Tobias A. F. König; Andreas Fery, "Strongly Coupled Plasmonic Modes on Macroscopic Areas via Template-Assisted Colloidal Self-Assembly". Nano Letters, 14 (12), 6863-6871 (2014).


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