Céline Noël oral presentation (SN2-Tue3-2-5)
Depth Profiling of Organic/Inorganic Optoelectronic Devices
1 university of Namur, rue de Bruxelles, 5000 Namur, Belgium
2 University of Namur, rue de Bruxelles 61, 5000 Namur, Belgium
3 Université de Namur, rue de Bruxelles 61, 5000 Namur, Belgium
Hybrid multilayered systems based on organic and inorganic layers stacks are more and more present in energy and electronic devices including solar cells, light emitting devices, sensors, microfluidics, etc. Organic materials typically provide for easy and cost effective deposition, tunable conductivities, malleability, transparency; however hybrid devices still struggle to overcome the performance and lifetime of semiconductor-based devices. Generally, device performances are improved by better understanding working mechanisms and degradation processes. In this framework, in-depth molecular analyses can provide for key information on the composition of each layer and diffusion at the interfaces.
The aim of the present work is to show how ToF-SIMS combined with low-energy (~500 eV) Cesium sputtering ion beam, allows identifying layers and interface effects in hybrid multilayer stacks, from the top electrode to the substrate. Starting from results on model sample structures (organic/metal/organic) , we will give clear examples of application of Cs+ depth profiles to reveal interface effects in complex hybrid devices such as organometal halide perovskite solar cells  and OLED structures.
Results show that characteristic molecular signals are preserved during the depth profile which is achieved within a reasonable sputtering time. Low-energy Cs+ appears as a versatile ion sputtering source compared to more conventional erosion sources such as Ar+, Xe+, O2+ or cluster sources (Arn+ or C60+) which are efficient on inorganic materials and inefficient with organics, and vice versa.
In parallel, we designed experiments on model samples to discriminate natural thermodynamic metallic migration in organic layers (during or after the deposition process) from the beam-induced atomic mixing during depth profiling.
This again indicates that ToF-SIMS can answer the increasing need to obtain molecular information on organic/inorganic interfaced materials, and low-energy Cs+ ions therefore offer a reliable solution to depth profiling hybrid materials.
.C. Noël and L. Houssiau, Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions. J Am Soc Mass Spectrom, 2016. 27(5): p. 908-16.
.F. Matteocci & Yan Busby, J.-J. Pireaux, G. Divitini, S. Cacovich, C. Ducati, and A. Di Carlo, Interface and Composition Analysis on Perovskite Solar Cells, ACS Appl. Mater. Interfaces, 2015 7, 26176−26183