Project Details
Projekt
Scattering Interfaces with Tailored Disorder and Binary Profiles
Subject Area
Synthesis and Properties of Functional Materials
Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
Term
from 2015 to 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 278744673
Optical interfaces that offer scattering properties on-demand are a long-standing vision. Such interfaces would find use in a plethora of devices for which optoelectronic elements such as solar cells or OLEDs constitute referential examples. The challenge in many of these applications is to tailor the interfaces towards optimal operation not just at a single wavelength but rather in an extended spectral domain. This precludes the consideration of highly ordered structures and prompts instead for disorder structures. However, not sheer randomness but disorder with tailored correlations are needed to unfold the full potential of disorder in light scattering. Furthermore, experimentally prepared disorder intrinsically contains certain correlations inherent to their respective fabrication method. Even for methods that allow to tune disorder to a large extend there always exist intrinsic limitations on the range the disorder can be tuned, which inhibits truly arbitrary tailored disorder.In this second funding period of the SPP, we endeavor to establish theoretical and scalable experimental tools to obtain large area disordered or disordered hyperuniform interfaces with a desired light scattering response. In particular, our approach enables us to investigate stacks of multiple interfaces of independently tailored disorder to overcome inherent limitations of the individual interface. This unlocks additional degrees of freedom facilitating truly arbitrary optical responses. In the first funding period, tailored disordered interfaces with a continuous height profile were investigated. Theoretically, we could determine the spectral power density as a key parameter. Experimentally, large-area disordered interfaces were prepared by overgrowing a disordered monolayer of spheres. The monolayer was deposited by a unique bottom-up technique that allows precise tuning of the lateral arrangement and size distribution of the spheres. The key element in this second funding period is the consideration of binary interfaces, i.e. nanohole or -disk layers, instead of continuous interfaces, which has major advantages. Theoretically, we seek to develop semi-analytical methods to address disordered textures with large modulations and proceed to exploit inverse modelling and shape optimization. Experimentally, we focus on exploring binary surface textures as such systems allow flexibility in choice of material and simplicity in obtaining a multi-stack structure with independently tailored interfaces. The disordered interfaces will be integrated into functional large-area devices such as solar cells or OLEDs. Particularly in these devices we expect multiple independent disordered interfaces to pay-off, as different requested functionalities can be handled with different interfaces. Moreover, with stacks of multiple disorder interfaces we can fundamentally probe the extent to which disordered systems are tuned towards randomness while still preserving certain correlations.
DFG Programme
Priority Programmes
