New efficient lighting device. Part 1. hybrid materials based on inorganic aerogel and metal-organic phosphor

A novel luminescent organic-inorganic hybrid material “LightSil” (hereinafter referred to as HM-LS) has been fabricated. Tris (8-hydroxyquinolate)aluminum (Alq3) purified by vacuum sublimation to 99.999 ​wt% was used as an organic phosphor. Silica aerogel was used as an inorganic matrix. Alq3 intercalation into aerogel structure did not strongly influence on the HM-LS morphology characteristics comparing with the pure aerogel, which indicated that the intercalation had proceed on the molecular level. An aerogel based hybrid was supercritical dried in a carbon dioxide environment under a pressure of 120 ​bar, at 40 ​°C at a carbon dioxide consumption of 500 ​g/h. The synthesis conditions (TEOS:2-propanol ratio) has been optimized to make the HM-LS sample with the best photoluminescence (PL) characteristics. Analysis of the PL spectra showed that the PL peak maximum of HM-LS shifted to longer wavelengths, and the HM-LS spectrum itself broadened by 64%: FWHMAlq3 ​= ​73 ​nm, FWHMHM-LS ​= ​113 ​± ​3 ​nm relative to Alq3 powder PL spectrum. The latter indicated on a change in the electronic structure of Alq3 in HM-LS in comparison with the nominally pure Alq3 and this proved the formation of a new hybrid material.