Suchergebnisse

Light-emitting diodes (LEDs) based on organic-inorganic hybrid perovskites, in particular, 3D and quasi-2D ones, are in the fast development and their external quantum efficiencies (EQEs) have exceeded 10%, making them competitive candidates toward large-area and low-cost light-emitting applications allowing printing techniques. Similar to other LED categories, light out-coupling efficiency is an important parameter determining the EQE of perovskite LEDs (PeLEDs), which, however, is scarcely studied, limiting further efficiency improvement and understanding of PeLEDs. In this work, for the first time, optical energy losses in PeLEDs are investigated through systematic optical simulations, which reveal that the 3D and quasi-2D PeLEDs can achieve theoretically maximum EQEs of approximate to 25% and approximate to 20%, respectively, in spite of their high refractive indices. These results are consistent with the reported experimental data. This work presents primary understanding of the optical energy losses in PeLEDs and will spur new developments in the aspects of device engineering and light extraction techniques to boost the EQEs of PeLEDs. ; Funding Agencies|ERC [717026]; Carl Tryggers Stiftelse; European Commission [691210]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; National Basic Research Program of China [2016YFE0112000]; European Union [2016YFE0112000]; State Key Laboratory of Luminescent Materials and Devices at South China University of Technology [2017-skllmd-05]; State Key Lab of Silicon Materials at Zhejiang University [SKL2017-03]; China Scholarship Council [201506920047]; [2016-02051]