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 03/26 (Tue) Prof. Jae-Byum Chang (KAIST MSE) ADMINI 2019.03.22 9
Notice Regular 03/19 (Tue) Dr. YangKoo Cho (Korea Research Institute of Standard and Science) ADMINI 2019.03.18 95
Notice Regular 3/12 (Tue) Prof. Chang Dong Yoo (KAIST EE) ADMINI 2019.03.12 93
Notice Regular 2/26 (Tue) Dr. Hye-Young Kim (Senior Venture Association) ADMINI 2019.02.22 201
Notice Special 1/28 (Mon) Prof. Yongjin Lee (Shanghai Tech Univ.) ADMINI 2019.01.23 518
Notice Regular 12/4 (Tue) Prof. Doo Seok Jeong (Hanyang Univ., Department of MSE) ADMINI 2018.11.30 864
Notice Regular 11/27 (Tue) Prof. Seong-Jun Jeong (Soongsil Univ.) ADMINI 2018.11.26 709
249 Special 2/13 (Tue) Prof. Sungkyu Kim (Northwestern Univ) ADMINI 2018.01.31 540
248 Special 1/9 (Tue) Dr. Choon Won Byeon, ETRI ADMINI 2018.01.09 540
247 12/23 (Sat) Prof. Liangbing (Bing) Hu/Univ. of Maryland file ADMINI 2017.12.22 552
246 Regular 11/28 (Tue) Dr. Woo-Jin Lee (Ministry of Science and ICT.) ADMINI 2017.11.24 1203
245 Special 11/24 (Fri) Takashi NOGUCH (University of the Ryukyus) ADMINI 2017.11.23 878
244 Special 11/21 (Tue) Dr. Young Ki Lee (ETRI) file ADMINI 2017.11.20 1044
243 Special 11/22 (Wed) Prof. Sung Hoon Kang (Johns Hopkins University) file ADMINI 2017.11.20 1280
242 Regular 11/21 (Tue) Dr. Byoung Koun Min, (KIST) ADMINI 2017.11.17 1456
241 Special 11/13 (Mon) Dr. Hans Aage Hiuler (Danish Power System) ADMINI 2017.11.10 1524
240 Special 11/13 (Mon) Prof. Jens Oluf Jensen (Technical University of Denmark) ADMINI 2017.11.10 786
239 Regular 11/14 (Tue) Prof. Jae-Byum Chang (Sungkyunkwan Univ) ADMINI 2017.11.10 755
238 Regular 11/7 (Tue) Prof. Su-Mi Hur (Chonnam National University) ADMINI 2017.11.05 603
237 Regular 10/31 (Tue) Director Jang Sae Young (Samsung Electronics) ADMINI 2017.10.26 616
236 Special 11/6 (Mon) Prof. Redouane Borsali (Grenoble Alpes University) ADMINI 2017.10.26 773
235 Special 11/6 ~ 7 Prof. Erik Luijten (Northwestern University) file ADMINI 2017.10.25 642
234 Special 10/23 ~ 24 Prof. Paul C. McIntyre (Stanford University) file ADMINI 2017.10.25 566
233 Regular 10/24 (Tue) Prof. Sun-Jae Kim (Sejong, Univ) ADMINI 2017.10.20 1006
232 Special 10/19 (Thu) Prof. Sang Cheol, Jung (Suncheon University) ADMINI 2017.10.18 1328
231 Regular 10/10 (Tue) Dr. Joo Choi (POSCO) ADMINI 2017.09.29 2253
» Regular 9/26 (Tue) Prof. Tae-Woo Lee (Seoul National University) ADMINI 2017.09.22 1484
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