460508 Layer-Controlled Colloidal Dispersions of Two-Dimensional Organometal Halide Perovskites for Efficient Blue Light-Emitting Diodes

Monday, November 14, 2016: 1:18 PM
Continental 2 (Hilton San Francisco Union Square)
Jakub Jagielski, Sudhir Kumar and Chih-Jen Shih, Institute for Chemical and Bioengineering, DCHAB, ETH Z├╝rich, Zurich, Switzerland

Layer-Controlled Colloidal Dispersions of Two-Dimensional Organometal Halide Perovskites for Efficient Blue Light-Emitting Diodes

Jakub Jagielski, Sudhir Kumar, and Chih-Jen Shih*

Institute for Chemical and Bioengineering, DCHAB, ETH Zurich, Zurich, Switzerland

*Author to whom all correspondence should be addressed.  Email: chih-jen.shih@chem.ethz.ch

Abstract

Two-dimensional (2D) organometal halide perovskites exhibit the quantum confinement effect by reducing the thickness smaller than the Bohr radius, or ~10 unit cell thick (i.e., n < 10). Their colloidal dispersion is emerging as one of the most promising candidates for printable optoelectronics and nanocomposites. However, it is not yet possible to synthesize large quantities of high-photoluminescence-quantum-yield (PLQY > 20%) 2D perovskites with precisely controlled stacking, as is necessary for light-emitting diodes (LEDs). Here, we demonstrate a synthesis method for the large-scale production of monolayer (n = 1), trilayer (n = 3), and 5-layer (n = 5) 2D methylammonium lead bromide (MAPbBr3) colloidal dispersions, which exhibit blue PL emissions at ~431 nm, ~456 nm, and ~485 nm, respectively, with high PLQYs (50% - 80%). The carefully-controlled ligand chemistry allows small lateral size and surface passivation, minimizing the effects of self-quenching and downhill energy transfer. The high PLQY has led to a record-high external quantum efficiency (EQE) of 0.2% in the blue LED devices, representing a >500-fold increase compared to that of the best blue organometal halide perovskite LED reported so far. The solution-based process is expected to allow low-cost and high-throughput production, as well as the deposition of the new family of 2D materials onto arbitrary substrates.


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See more of this Session: Organic, Polymeric, and Hybrid Semiconductors
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