Blue nanocrystal perovskite LEDs have traditionally lagged behind their red and green cousins. Here, we discuss the reasons for this lag and propose solutions to these problems, producing high efficiency blue perovskite LEDs. We demonstrate the NiOx, a transport material in one of the highest performing devices to date, reduces the performance of nanocrystals near to the interface. By replacing it with an alternative transport structure, we show that the nanocrystal emission is unperturbed. We then build full LEDs out of this transport structure, increasing the EQE from 0.03% to 0.50%, the highest for inorganic perovskite nanocrystals at this wavelength. We further show that the benefits of this transport structure relax as the energetics redshift, as our blue-green devices match those from literature. These results are a useful step forward towards commercially relevant perovskite LEDs.

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Daniel Congreve, Mahesh Gangishetty, Shaocong Hou, and Qimin Quan, "Efficient blue perovskite nanocrystal light emitting diodes (Conference Presentation)," Proc. SPIE 10724, Physical Chemistry of Semiconductor Materials and Interfaces XVII, 107240B (Presented at SPIE Nanoscience + Engineering: August 21, 2018; Published: 17 September 2018); https://doi.org/10.1117/12.2320324.5836012278001.