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 5/21 (Tue) Emeritus Prof. Joong Keun Park (Dept. of MSE, KAIST) ADMINI 2019.05.17 13
Notice Regular 5/17 (Tue) Prof. Su-Hyun Gong (Dept. of Physics, Korea Univ.) ADMINI 2019.05.10 167
Notice Special 5/7 (Tue) Prof. Dr. -ing. Dierk Raabe (MPIE) ADMINI 2019.04.30 111
Notice Regular 4/30 (Tue) Prof. Min Hyuk Park (School of MSE, Pusan National Univ.) ADMINI 2019.04.25 299
Notice Regular 4/23 (Tue) Prof. Seungwu Han (Dept. of MSE, SNU) ADMINI 2019.04.19 123
Notice Regular 4/9 (Tue) Prof. Ji Young Jo (GIST, School of MSE) ADMINI 2019.04.05 142
Notice Regular 4/2 (Tue) Prof. Li Oi Lun (Dept. of MSE, Pusan National Univ.) ADMINI 2019.03.29 177
256 Regular 3/27 (Tue) Prof. Seungbum Hong (KAIST MSE) ADMINI 2018.03.26 657
255 Regular 3/20 (Tue) Prof. Jung In-Ho (Seoul National University, MSE) ADMINI 2018.03.20 578
254 Regular 3/13 (Tue) Prof. Jong-Beom Baek (School of Energy and Chemical Engineering, UNIST) ADMINI 2018.03.13 542
253 Regular 3/6 (Tue) Prof. Seok-Young Ryu (KAIST CS) ADMINI 2018.03.05 444
252 Regular 2/27 (Tue) Dr. Jin-Woo Han (NASA) ADMINI 2018.02.27 518
251 Special 2/20 (Tue) Dr. Jae Beom Jang (Sungkyunkwan Univ) ADMINI 2018.02.19 489
250 Special 2/8 (Thu) Prof. Pei-Chen Su (Nanyang Technological University) file ADMINI 2018.02.05 521
249 Special 2/13 (Tue) Prof. Sungkyu Kim (Northwestern Univ) ADMINI 2018.01.31 546
248 Special 1/9 (Tue) Dr. Choon Won Byeon, ETRI ADMINI 2018.01.09 546
247 12/23 (Sat) Prof. Liangbing (Bing) Hu/Univ. of Maryland file ADMINI 2017.12.22 559
246 Regular 11/28 (Tue) Dr. Woo-Jin Lee (Ministry of Science and ICT.) ADMINI 2017.11.24 1214
245 Special 11/24 (Fri) Takashi NOGUCH (University of the Ryukyus) ADMINI 2017.11.23 890
244 Special 11/21 (Tue) Dr. Young Ki Lee (ETRI) file ADMINI 2017.11.20 1052
243 Special 11/22 (Wed) Prof. Sung Hoon Kang (Johns Hopkins University) file ADMINI 2017.11.20 1285
242 Regular 11/21 (Tue) Dr. Byoung Koun Min, (KIST) ADMINI 2017.11.17 1478
241 Special 11/13 (Mon) Dr. Hans Aage Hiuler (Danish Power System) ADMINI 2017.11.10 1698
240 Special 11/13 (Mon) Prof. Jens Oluf Jensen (Technical University of Denmark) ADMINI 2017.11.10 792
239 Regular 11/14 (Tue) Prof. Jae-Byum Chang (Sungkyunkwan Univ) ADMINI 2017.11.10 759
238 Regular 11/7 (Tue) Prof. Su-Mi Hur (Chonnam National University) ADMINI 2017.11.05 612
237 Regular 10/31 (Tue) Director Jang Sae Young (Samsung Electronics) ADMINI 2017.10.26 621
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