Metal-organic frameworks (MOFs) enable the design of host-guest systems with specific properties.I nt his work, we showh ow the confinement of anthracene in aw ellchosen MOF host leads to reversible yellow-to-purple photoswitching of the fluorescence emission. This behavior has not been observed before for anthracene,e ither in pure form or adsorbed in other porous hosts.The photoresponse of the hostguest system is caused by the photodimerization of anthracene, which is greatly facilitated by the pore geometry,c onnectivity, and volume as well as the structural flexibility of the MOF host. The photoswitching behavior was used to fabricate photopatternable and erasable surfaces that, in combination with data encryption and decryption, hold promise in product authentication and secure communication applications.

We have measured for the first time the external quantum efficiency (EQE) of silver clusters containing zeolites (henceforth referred to as silver-clusters zeolite composites). These materials, fabricated by silver cation exchange followed by a thermal autoreduction process, have EQEs up to 69%. Because of their unique spectral features such as large Stokes shift and high EQE, these materials could be potentially used as phosphors for the fabrication of fluorescent lamps and as wavelength convertors in solar cells. An EQE comparison between less pure commercial silverloaded zeolites and self-synthesized silver-zeolites showed the importance of the chemical and optical purity of the starting host material. Besides this, the zeolite topology and silver content play an important role on the luminescent performance of such materials. The ability to reliably measure the EQE enabled us to further optimize the synthesis of silver-zeolite composites. A new reduction−oxidation cycle is demonstrated not only to improve the luminescent performance of the silver-zeolite composites but also to enhance their water stability.

We report the formation of luminescent silver clusters in zeolites by a fast, highly accurate, and controlled activation of silver ions entrapped in sodalite cages of LTA and FAU zeolites using high-brilliance soft X-rays. The activated luminescent samples were investigated by employing a combination of stationary and time-resolved spectroscopic techniques.

Metal-organic frameworks (MOFs) enable the design of host-guest systems with specific properties.I nt his work, we showh ow the confinement of anthracene in aw ellchosen MOF host leads to reversible yellow-to-purple photoswitching of the fluorescence emission. This behavior has not been observed before for anthracene,e ither in pure form or adsorbed in other porous hosts.The photoresponse of the hostguest system is caused by the photodimerization of anthracene, which is greatly facilitated by the pore geometry,c onnectivity, and volume as well as the structural flexibility of the MOF host. The photoswitching behavior was used to fabricate photopatternable and erasable surfaces that, in combination with data encryption and decryption, hold promise in product authentication and secure communication applications.

The temperature- and co-cation-dependent photoluminescence of zeolite confined Ag clusters was systematically investigated. Bright polychromatic emission and intriguing excited-state dynamics were observed and a kinetic model was proposed.