White-Light Emission from Dual-Way Photon Energy Conversion in a Dye-Encapsulated Metal-Organic Framework

The design of white-light phosphors is attractive in solid-state lighting (SSL) and related fields. A new strategy in obtaining white light emission (WLE) from dual-way photon energy conversion in a series of dye@ MOF (LIFM-WZ-6) systems is presented. Besides the traditional UV-excited onephoton absorption (OPA) pathway, white-light modulation can also be gained from the combination of NIR-excited green and red emissions of MOF backbone and encapsulated dyes via two-photon absorption (TPA) pathway. As a result, downconversion OPA white light was obtained for RhB+@ LIFMWZ-6 (0.1 wt%), BR-2+@ LIFM-WZ-6 (2 wt%), and APFG+@ LIFM-WZ-6 (0.1 wt%) samples under 365 nm excitation. RhB+@ LIFM-WZ-6 (0.05 wt%), BR-2+@ LIFM-WZ-6 (1 wt%) and APFG+@ LIFM-WZ-6 (0.05 wt%) exhibit upconversion TPA white light under the excitation of 800, 790, and 730 nm, respectively. This new WLE generation strategy combines different photon energy conversion mechanisms together.