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Nanoparticulate double-heterojunction photocatalysts comprising TiO 2(Anatase) /WO 3 /TiO 2(Rutile) were produced by a sol–gel method. The resulting photocatalysts exhibit clear synergistic effects when tested toward the degradation of methyl orange under both UV and visible light. Kinetic studies indicate that the degradation rate on the best double-heterojunction photocatalyst (10 wt % WO 3 -TiO 2 ) depends mainly on the amount of dye concentration, contrary to pure oxides in which the degradation rate is limited by diffusion-controlled processes. The synergistic effects were confirmed through systematic and careful studies including holes and OH radical formation, X-ray diffraction, electron microscopy, elemental analysis, UV–vis diffuse reflectance spectroscopy, and surface area analysis. Our results indicate that the successful formation of a double heterojunction in the TiO 2(Anatase) /WO 3 /TiO 2(Rutile) system leads to enhanced photoactivity when compared to individual oxides and commercial TiO 2 P25.

Colloidal quantum dot light-emitting diodes (QLEDs) simultaneously exhibiting high external quantum efficiency (EQE) and operation stability are achieved via a simple solution processing. A silver bis(trifluoromethanesulfonyl)imide treatment that is used to chemically dope the poly(3,4ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) hole injection layer (HIL) is proposed. The ionic liquid salt acts as an effective p-dopant for high charge concentrations; and it raises the work functions and surface potentials of the PEDOT:PSS HIL for an interface energy band alignment. Benefiting from a raised hole mobility and a better charge mobility balance, the processing-simple colloidal red QLEDs yielded the highest EQE of up to 17.4%. In particular, a very broad plateau of EQE values over 16.5% in the brightness of 400-10 000 cd m −2 is obtained. Moreover, the packaged QLEDs exhibit an excellent operation stability in ambient air. The T 95 (time for the device brightness to decrease to 95% of its initial brightness) at an initial brightness of 1000 cd m −2 is 4160 h. The work highlights a promising ionic liquid strategy to guide the development of high-performance and costeffective QLEDs.