Aim of this WP is the development of a single cell vehicle suitable for the evaluation of different stacks of CSL. Such a vehicle will be fabricated by Micron and exchanged with partners for the deposition of CSL by Aachen University and PDI. The developed device will allow a benchmark between different deposition technique and stacks basing on the target defined in Milestone M1 reported in D3.1 and will lead to a final active material choice. An assessment of the electrical performance of the newly developed device with the selected material will be also done as requested by milestone M7 reported in D3.5.