Monolithic High Performance Surface Anchored Metal−Organic Framework Bragg Reflector for Optical Sensing

We report the fabrication of monolithic dielectric mirrors by stacking layers of metal–organic frameworks (MOFs) and indium tin oxide (ITO). Such Hybrid Photonic Band-Gap (PBG) Materials exhibit high optical quality (reflectivities of 80%) and are color tunable over the whole visible range. While the ITO deposition is accomplished by using a conventional sputter process, the highly porous MOF layers are deposited using liquid-phase epitaxy (LPE), therefore yielding crystalline, continuous, and monolithic HKUST-1 SURMOF thin films with high optical performance. We demonstrate the optical sensing capabilities of these monolithic and porous Bragg stacks by investigating the chemo-responsive optical properties (PBG shift and modulation of the intensity of the PBG maximum) upon the exposure to different organic solvents.