The authors would like to acknowledge the EC funding for different projects mentioned in the article and especially OptiNanoPro under Grant Agreement No. 686116. They would like to also thank the project partners Fibroline, Bioinicia S.L., Lajovic TUBA d.o.o. and Fraunhofer IVV for their contributions. [1] Bugnicourt E. et al., Recent Prospects in the Inline Monitoring of Nanocomposites and Nanocoatings by Optical Technologies, Nanomaterials 2016, 6(8) [2] THIME, EC-funded project Thinfilm measurements on organic photovoltaic (OPV) layers, Grant Agreement no: 315665, Final Report Summary, 2016, available from: , accessed 10/04/2019. ...