신소재공학과

Seminar

Date 20170926 

■ Title:  Next LEDs: Metal Halide Perovskite Light-Emitting Diodes


■ Speaker: Prof. Tae-Woo Lee (Dept. of MSE, Seoul National University) 

 

■ Date and time: 26th of September, (Tue) 16:00

 

■ Venue: Applied Engineering Dpt. Bd W1 Multimedia Lecture Hall (1st Floor)

 

 Host : Prof. Duk young Jeon

  

 Abstract : Metal halide perovskites are emerging high color-purity emitters with low material cost. However, low electroluminescence (EL) efficiency at room temperature is a challenge that should be overcome. Here, we present efficient perovskite light-emitting diodes (PeLEDs) using various strategies to overcome the EL efficiency limitations where the perovskite layers are in forms of (1) 3D crystal structures, (2) quasi-2D crystal structures and (3) nanoparticles (NPs). First, to improve EL efficiency of PeLEDs based on 3D crystal structures, we introduced a self-organized buffer hole injection layer to reduce the hole injection barrier and block the exciton quenching at the interface. The high-efficiency methylammonium lead bromide (MAPbBr3) and CsPbBr3 PeLEDs were realized based on the buffer hole injection layers and the temperature dependence of EL in the CsPbBr3 PeLEDs was systematically investigated and related with ion migration, EL quenching pathways and electron-phonon coupling. Furthermore, we found that the formation of metallic lead atoms causes strong exciton quenching, and it was prevented by finely increasing the molar proportion of MABr in MAPbBr3 solution. Also, we suggest that the efficiency in PeLEDs can be increased by decreasing MAPbBr3 grain sizes and consequently improving uniformity and coverage of MAPbBr3 layers. Using these strategies, a high-efficiency PeLEDs was realized (current efficiency = 42.9 cd/A). High-efficiency flexible MAPbBrPeLEDs based on graphene anode were also developed for the first time. Chemically inert graphene avoids quenching of excitons by diffused metal atom species from indium tin oxide. Second, quasi-2D perovskites were studied because of the advantages of quasi-2D perovskites such as the enhancement of film quality, exciton confinement and reduced trap density, and quasi-2D PeLEDs with high efficiency and brightness were demonstrated. Finally, perovskite NPs were studied because they can show high luminescence efficiency and high color-purity in both solution states and film states, and high efficiency PeLEDs based on MAPbBr3 and formaminidium lead bromide (FAPbBr3) NPs were also fabricated.

No. Subject Author Date Views
Notice 5/15 (Tue) Prof. Myung Gil Kim (Dept. of Chemistry, Chung-Ang Univ.) ADMINI 2018.05.15 159
Notice 5/8 (Tue) Prof. Ju-Young Kim (UNIST MSE) ADMINI 2018.05.09 222
Notice 5/1 (Tue) Prof. Duk-Yong Yoon (KAIST MSE) ADMINI 2018.04.30 402
Notice 4/24 (Tue) Kyeong Ho Chang (CEO, Innox Advanced Materials) ADMINI 2018.04.23 424
Notice 4/10 (Tue) Prof. Ki Jun, Yu (Yonsei Univ., School of Electrical and Electronic Engineering) ADMINI 2018.04.09 516
Notice 4/3 (Tue) Master Byung-Gi Choi (Samsung Advanced Institute of Technology) ADMINI 2018.04.02 431
Notice 3/27 (Tue) Prof. Seungbum Hong (KAIST MSE) ADMINI 2018.03.26 402
Notice 3/20 (Tue) Prof. Jung In-Ho (Seoul National University, MSE) ADMINI 2018.03.20 269
Notice 3/13 (Tue) Prof. Jong-Beom Baek (School of Energy and Chemical Engineering, UNIST) ADMINI 2018.03.13 266
Notice 3/6 (Tue) Prof. Seok-Young Ryu (KAIST CS) ADMINI 2018.03.05 237
Notice 2/27 (Tue) Dr. Jin-Woo Han (NASA) ADMINI 2018.02.27 291
Notice 2/20 (Tue) Dr. Jae Beom Jang (Sungkyunkwan Univ) ADMINI 2018.02.19 262
Notice 2/8 (Thu) Prof. Pei-Chen Su (Nanyang Technological University) ADMINI 2018.02.05 267
Notice 2/13 (Tue) Prof. Sungkyu Kim (Northwestern Univ) ADMINI 2018.01.31 340
Notice 1/9 (Tue) Dr. Choon Won Byeon, ETRI ADMINI 2018.01.09 372
Notice 12/23 (Sat) Prof. Liangbing (Bing) Hu/Univ. of Maryland ADMINI 2017.12.22 392
Notice 2017 The Fall Semester Seminar ADMINI 2017.09.08 2903
241 11/21 (Tue) Dr. Byoung Koun Min, (KIST) ADMINI 2017.11.17 1356
240 11/13 (Mon) Dr. Hans Aage Hiuler (Danish Power System) ADMINI 2017.11.10 718
239 11/13 (Mon) Prof. Jens Oluf Jensen (Technical University of Denmark) ADMINI 2017.11.10 687
238 11/14 (Tue) Prof. Jae-Byum Chang (Sungkyunkwan Univ) ADMINI 2017.11.10 715
237 11/7 (Tue) Prof. Su-Mi Hur (Chonnam National University) ADMINI 2017.11.05 533
236 10/31 (Tue) Director Jang Sae Young (Samsung Electronics) ADMINI 2017.10.26 548
235 11/6 (Mon) Prof. Redouane Borsali (Grenoble Alpes University) ADMINI 2017.10.26 643
234 11/6 ~ 7 Prof. Erik Luijten (Northwestern University) file ADMINI 2017.10.25 599
233 10/23 ~ 24 Prof. Paul C. McIntyre (Stanford University) file ADMINI 2017.10.25 526
232 10/24 (Tue) Prof. Sun-Jae Kim (Sejong, Univ) ADMINI 2017.10.20 960
231 10/19 (Thu) Prof. Sang Cheol, Jung (Suncheon University) ADMINI 2017.10.18 1302
230 10/10 (Tue) Dr. Joo Choi (POSCO) ADMINI 2017.09.29 2207
» 9/26 (Tue) Prof. Tae-Woo Lee (Seoul National University) ADMINI 2017.09.22 1116
228 9/19 (Tue) Representative Sang Min Lee (Congressman) ADMINI 2017.09.15 1202
227 9/12 (Tue) Monika Fleischer(Eberhard Karls University Tübingen) ADMINI 2017.09.14 805
226 9/12 (Tue) Prof. Pil Jin, Yoo (Sungkyunkwan Univ) ADMINI 2017.09.08 1334
225 9/11 (Mon) Won Joon, Cho (Lawrence Berkeley National Lab, Berkeley) ADMINI 2017.09.06 1340
224 9/13 (Wed) Dr. In Kyung Yoo (SAIT) ADMINI 2017.09.06 1566
223 8/24 (Tue) Prof. Jong Min Yuk (MSE KAIST) ADMINI 2017.08.24 1588