신소재공학과

Seminar

Extra Form
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.


List of Articles
No. Category Subject Author Date Views
Notice Regular 9/18 (Tue) Prof. Seong Jun Kang (Kyung Hee Univ.) ADMINI 2018.09.17 9
Notice Regular 9/11 (Tue) Dr. Byeongdu Lee (Argonne National Laboratory) ADMINI 2018.09.07 94
Notice Regular 9/4 (Tue) Prof. Kibum Kang (Department of MSE, KAIST) ADMINI 2018.09.03 99
Notice Regular 8/28 (Tue) Prof. Kyung-Min Kim (Department of MSE, KAIST) ADMINI 2018.08.24 140
Notice Special 8/24 (Fri) Prof. Joel W. Ager III (UC Berkeley, Lawrence Berkeley National Laboratory) file ADMINI 2018.08.20 158
Notice Special 8/23 (Thu) Prof. Jeehwan Kim (MIT, USA) file ADMINI 2018.08.20 174
Notice Special 8/23 (Thu) Prof. YANGUANG LI (Soochow University) file ADMINI 2018.08.20 91
233 Regular 10/24 (Tue) Prof. Sun-Jae Kim (Sejong, Univ) ADMINI 2017.10.20 976
232 Special 10/19 (Thu) Prof. Sang Cheol, Jung (Suncheon University) ADMINI 2017.10.18 1315
231 Regular 10/10 (Tue) Dr. Joo Choi (POSCO) ADMINI 2017.09.29 2227
» Regular 9/26 (Tue) Prof. Tae-Woo Lee (Seoul National University) ADMINI 2017.09.22 1134
229 Regular 9/19 (Tue) Representative Sang Min Lee (Congressman) ADMINI 2017.09.15 1213
228 Special 9/12 (Tue) Monika Fleischer(Eberhard Karls University Tübingen) ADMINI 2017.09.14 821
227 Regular 2017 The Fall Semester Seminar file ADMINI 2017.09.08 2981
226 Regular 9/12 (Tue) Prof. Pil Jin, Yoo (Sungkyunkwan Univ) ADMINI 2017.09.08 1345
225 Special 9/11 (Mon) Won Joon, Cho (Lawrence Berkeley National Lab, Berkeley) ADMINI 2017.09.06 1362
224 Special 9/13 (Wed) Dr. In Kyung Yoo (SAIT) ADMINI 2017.09.06 1582
223 Regular 8/24 (Tue) Prof. Jong Min Yuk (MSE KAIST) ADMINI 2017.08.24 1599
222 Special 6/16 (Fri) Dr. Bok Yeop Ahn (Harvard University) ADMINI 2017.06.13 3157
221 Special 6/12 (Mon) Prof. C. Suryanarayana (University of Central Florida) ADMINI 2017.06.05 1335
220 Special 6/2 (fri) Robert M. Ulfig (CAMECA Instruments Inc) ADMINI 2017.06.01 1332
219 Special 6/5 (Mon) Dr. Aron Varga/Dr. Andriy Lotnyk ADMINI 2017.05.30 1418
218 Regular 5/30 (Tue) Prof. Chang Hyeon Ko (Sookmyung Univ) ADMINI 2017.05.26 1539
217 Regular 5/23 (Tue) Prof. Don Hyeong Ha (Choongang university) ADMINI 2017.05.19 1127
216 Regular 5/16 (Tue) Prof. Eun Sun Cho (KAIST CBE) ADMINI 2017.05.10 1338
215 Regular 5/2 (Tue) Prof. Seung Woo Lee (SKKU) ADMINI 2017.04.28 1423
214 Regular 4/25 (Tue) Prof. Hyeong Sup Choi (Seoul National University of Science and Technology) ADMINI 2017.04.20 1248
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