Perovskite Quantum Dots and Light Emitting Devices
Yu Zhang a
a State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
nanoGe Perovskite Conferences
Proceedings of International online conference on Hybrid materials and optoelectronic devices (HYBRIDOE)
Online, Spain, 2020 December 15th - 17th
Organizers: Xueqing Xu, Baomin Xu, Hin-Lap (Angus) Yip and Xinhua Zhong
Invited Speaker, Yu Zhang, presentation 033
DOI: https://doi.org/10.29363/nanoge.hybridoe.2020.033
Publication date: 4th December 2020

    Bulk halide perovskites are crystalline semiconductors with exceptional optoelectronic properties, such as low trap densities, long carrier diffusion lengths, high and balanced charge-carrier mobilities. Successes have been achieved for employing this class of materials in photovoltaic cells, lasers, photodetectors, and light-emitting diodes (LEDs). Fully inorganic perovskite quantum dots (QDs), CsPbX3 (X = Cl, Br, I), with narrow size distribution, narrow emission line width, as well as high PL QY without surface shelling, have been developed. Their emission lights also cover the entire visible spectral region and can be easily adjusted by controlling their composition and crystal size, but their synthesis can be done with much low temperatures and simple procedures that are more facile and precise than cadmium chalcogenide based QDs.

We focus on the three issues of perovskite QD-based LEDs including stability, efficiency and  toxicity. (1) Perovskite QD/silica composites and gels with excellent PL properties of narrow line-width and high PL QY were synthesized by slowly hydrolyzing the organosilicon capping agent in situ, which showed the significantly improved air stability; (2) We demonstrated that through a simple post treatment to the perovskite QDs with polyethylenimine, the surface defects of the perovskite QDs could be well passivated, leading to great enhancements on their absolute photoluminescence quantum yield and photoluminescence lifetime. Through using a well-passivated perovskite QD film and optimizing the charge balance, we achieved an electroluminescence LED with an external quantum efficiency (EQE) of 15.1 %; (3) The highly luminescent Pb-free perovskite QDs were prepared and demonstrated an efficient electroluminescence LED.

 

References:
[1] C Yin, L Chen, N Song, Y Lv, F Hu, C Sun, W W Yu, C Zhang, X Wang, Y Zhang*, and M Xiao, Physical Review Letters, 2017, 119, 026401.

[2] C Sun, Y Zhang,* C Ruan, C Yin, X Wang, Y Wang, and W W. Yu, Adv. Mater., 2016, 28, 10088.

[3] F Hu, C Yin, H Zhang, C Sun, W W Yu, C Zhang, X Wang, Y Zhang*, and M Xiao, Nano Lett., 2016, 16, 6425.

[4] Y Xu, Q Chen, C Zhang, R Wang, H Wu, X Zhang, G Xing, W W Yu, X Wang, Y Zhang, and M Xiao, J. Am. Chem. Soc., 2016, 138, 3761.

[5] H Zhang, X Fu, Y Tang, H Wang, C Zhang, W W Yu, X Wang, Y  Zhang, and M Xiao, Phase segregation due to ion migration in all-inorganic mixed-halide perovskite nanocrystals, Nature Communications, 2019, 10, 1088.

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