Nanometrology assisted chemical fabrication: direct laser writing of porphyrins onto complex surfaces

The association of operando monitoring methodologies with micro and nanoscale surface modification strategies has recently been shown to enable the preparation of complex yet highly precise organic functional surfaces. While promising, such demonstrations have so far been limited to model systems, consisting on minimally functionalized aryl radicals. With a growing demand for more sophisticated surfaces, bearing multiple functions, a demonstration of the generality of the strategy, including chemically complex moieties and surfaces is deeply needed. In this work, we aim to fill this gap by preparing tetraphenyl porphyrin derivatives modified to become radical precursors that can be activated with light. Operando optical monitoring is used to non-invasively analyze their grafting behavior in different conditions, optimizing the reaction and enabling modification of inert glass surfaces with high precision (30 atto L). We demonstrate that the methodology is compatible with direct laser writing technologies, and use it to prepare photophysically active surfaces with high resolution. We demonstrate that the instrinsic emissive properties of Tetraphenylporphyrin derivatives are well preserved, and that several surface modifing steps can be sequentially stacked, leading to the preparation of surfaces with multiple functions. By controlling the microscale distribution of chemical groups with different photophysical properties, we demonstrate that complex chemical designs can be readily and reliably implemented. This work therefore shows that light activated radical pathways can be broadly used to modify surfaces, opening interesting new perspectives for the implementation of functional materials.