Interface Engineering in Organic Devices

DOI: 10.1002/admt.201900303 endows them with sensitivity and selectivity towards specific analytes. Interface engineering has to be regarded, therefore, as an enabling strategy for achieving unprecedented multifunctional and multi-responsive organic devices with full control over the correlation between structure and function. This special section of Advanced Materials Technologies reports a few enlightening recent experimental and chemical-design approaches aimed at controlling and tuning some technologically Prof. P. Samori University of Strasbourg CNRS ISIS UMR 7006, 8 alleé Gaspard Monge, F-67000 Strasbourg, France E-mail: samori@unistra.fr Prof. F. Biscarini Dept. of Life Sciences Università di Modena e Reggio Emilia Via Campi 103, I-41125 Modena, Italy E-mail: fabio.biscarini@unimore.it Prof. F. Biscarini Center for Translational Neurosciences of Speech and Cognition (CTNSC)-Istituto Italiano di Tecnologia Via Fossato di Mortara 17–19, I-44100 Ferrara, Italy Interfaces are ubiquitous in nature and play a key role in many fundamental physical and chemical processes. In organic electronic devices, where charge injection, charge transport, and trapping are indeed interfacial phenomena, the intrinsic properties of the active materials, their processability and their response in devices can be modulated and even disguised by mismatched interfacial properties, sometimes hampering the concept of “properties by molecular design” which is one of the pillars of organic electronics. Tailoring the interface and thus achieving full control over their properties in fabrication processes of organic devices, and optimizing them for device response, is technologically challenging due to the intertwining of complex phenomena during the assembly of molecular and supramolecular architectures on technological surfaces. Examples include the control of molecular orientation, nucleation and growth of molecularly ordered domains which affect the surface roughness and lateral morphological correlations, as well as the coexistence of misoriented crystalline domains, their size distribution and the extent of domain boundaries. Dynamic processes such as wetting, dewetting and ripening govern the occurrence of (re-)crystallization yielding the formation of inhomogeneous thin films on specific length scales during the device fabrication, and can also be subjected to re-adjustment while the device is “in-action” thereby affecting its time-stability. From the more functional viewpoint, the boosting of charge injection can be attained via the optimization of energy level alignment and the minimization of energy barriers through the physisorption or chemisorption of suitably designed molecular building blocks. Moreover, density of charged surface states, (local) doping and trapping can be modulated via non-covalent surface interactions. The bottom-up engineering of the physical chemistry of the interfaces is an effective approach towards the multiscale control of supramolecular organization and energy (dis-)order of the device interfaces, such as organic/dielectric, organic/ electrode, organic/organic, and organic/ambient. The approach is also central to the design of chemoand biosensors, as it Paolo Samorì is Distinguished Professor at the Université de Strasbourg, Director of the Institut de Science et d’Ingénierie Supramoléculaires (ISIS). He obtained a Laurea at University of Bologna and his PhD at the Humboldt University of Berlin. He was permanent research scientist at Istituto per la Sintesi Organica e la Fotoreattività of the Consiglio Nazionale delle Ricerche of Bologna. His research interests encompass nanochemistry, supramolecular sciences, materials chemistry, and scanning probe microscopies with a specific focus on graphene and other 2D materials as well as functional organic/ polymeric and hybrid nanomaterials for application in optoelectronics, energy and sensing.