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Proceedings Paper

Polymer blend lithography: a versatile approach for the fabrication of disordered light harvesting nanostructures (Conference Presentation)
Author(s): Yidenekachew J. Donie; Anna Osypka; Radwanul H. Siddique; Tsvetelina Merdzhanova; Vikas R. Voggu ; Brian A. Korgel; Jan B. Preinfalk; Amos Egel; Hendrik Hölscher; Uli Lemmer; Guillaume Gomard

Paper Abstract

Over the last couple of years, photonic materials with tailored -i.e. with deliberately introduced- structural disorder have attracted considerable interest in photovoltaics due to their extended spectral and angular range of effectiveness [1]. Notably, quasi-random nanostructures realized by e-beam lithography (EBL) have been integrated in solar cells as broadband light trapping elements, and have proved to approach the theoretical (Lambertian) limit [2]. Despite recent research efforts aiming at increasing the EBL writing speed [3], alternative routes based on self-assemblies still possess major advantages for an industrial implementation of disordered structures as they allow to rapidly process them over large areas (>>cm2). In this communication, we show that the up-scalable polymer blend lithography technique can be used as a versa-tile platform for fabricating 2D planar, disordered nanostructures that can be exploited in both top-down and bottom-up strategies. Tailored disorder is achieved here by adjusting the process parameters (polymer blend composition and deposition conditions), enabling to tune the morphology and the spatial distribution of the nanostructures produced, and in turn their light harvesting properties. We first use our approach to pattern a resist etching mask, which is employed for transferring disordered nanoholes into a thin hydrogenated amorphous silicon layer by dry etching (top-down route). We report an enhancement of its integrated absorption of +90% under normal incidence, and of up to +200% at large incident angles with respect to an unprocessed absorber [4]. In a second example, we demonstrate that similar structures can serve as a template in a bottom-up configuration, whereby copper indium diselenide nanocrystals are infiltrated into the disordered nano-holes formed in a resist layer. This route, paving the way to wet-processable "photonized" absorbers, is compared to a previous work relying on a serial writing process [5], and the optical properties of the resulting patterned absorbing layers are analysed. We finally elaborate on the significance of these findings for the reverse problem, namely for light extraction in broadband light-emitting diodes. References [1] Burresi, M., Pratesi, F., Riboli, F., & Wiersma, D. S. (2015). Complex photonic structures for light harvesting. Advanced Optical Materials, 3(6), 722-743. [2] Martins, E. R., Li, J., Liu, Y., Depauw, V., Chen, Z., Zhou, J., & Krauss, T. F. (2013). Deterministic quasi-random nanostructures for photon control. Nature communications, 4, 2665. [3] Li, K., Li, J., Reardon, C., Schuster, C. S., Wang, Y., Triggs, G. J., ... & Krauss, T. F. (2016). High speed e-beam writing for large area photonic nanostructures—a choice of parameters. Scientific reports, 6. [4] Siddique, R. H., Donie, Y. J., Gomard, G., Yalamanchili, S., Merdzhanova, T., Lemmer, U., & Hölscher, H. (2017). Bioinspired phase-separated disordered nanostructures for thin photovoltaic absorbers. Science Advances, 3(10), e1700232. [5] Dottermusch, S., Quintilla, A., Gomard, G., Roslizar, A., Voggu, V. R., Simonsen, B. A., ... & Richards, B. S. (2017). Infiltrated photonic crystals for light-trapping in CuInSe2 nanocrystal-based solar cells. Optics Express, 25(12), A502-A514.

Paper Details

Date Published: 23 May 2018
Proc. SPIE 10688, Photonics for Solar Energy Systems VII, 106880U (23 May 2018); doi: 10.1117/12.2312079
Show Author Affiliations
Yidenekachew J. Donie, Karlsruher Institut für Technologie (Germany)
Anna Osypka, Karlsruher Institut für Technologie (Germany)
Radwanul H. Siddique, California Institute of Technology (United States)
Tsvetelina Merdzhanova, Forschungszentrum Jülich GmbH (Germany)
Vikas R. Voggu , The Univ. of Texas at Austin (United States)
Brian A. Korgel, The Univ. of Texas at Austin (United States)
Jan B. Preinfalk, Karlsruher Institut für Technologie (Germany)
Amos Egel, Karlsruher Institut für Technologie (Germany)
Hendrik Hölscher, Karlsruher Institut für Technologie (Germany)
Uli Lemmer, Karlsruher Institut für Technologie (Germany)
Guillaume Gomard, Karlsruher Institut für Technologie (Germany)

Published in SPIE Proceedings Vol. 10688:
Photonics for Solar Energy Systems VII
Ralf B. Wehrspohn, Editor(s)

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