Pentacene molecular layers for the photoelectrochromic modulation of NIR absorption in plasmonic indium-tin oxide

As prototypical organic semiconductor material, pentacene is praised in numerous electronic and optical systems for its high charge carrier mobility and important photoabsorbing capacities; still, charge generation, transfer and collection remain a critical challenge, especially when considering hybrid structures with inorganic metal oxides as charge acceptors. This study addresses the deposition of pentacene molecular layers onto indium-tin oxide (ITO) nanostructures that allow for a dynamic modulation of near-infrared radiations in intelligent glazing systems, i.e. plasmonic electrochromism. Multi-modal surface characterizations highlight a reorganization of pentacene molecules, transitioning from a perpendicular orientation when deposited on bare, non-ITO surfaces to more random organization, involving standing-up and face-on orientations, when deposited on ITO. Steady-state and ultrafast spectroscopies further reveal an enhanced optical absorption in the near-infrared resulting from the photoexcitation of the ITO – pentacene bilayers, therefore holding promise as novel photoelectrochromic structures for advanced smart windows applications.