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 2/20 (Tue) Dr. Jae Beom Jang (Sungkyunkwan Univ) ADMINI 2018.02.19 1
Notice 2/8 (Thu) Prof. Pei-Chen Su (Nanyang Technological University) ADMINI 2018.02.05 18
Notice 2/13 (Tue) Prof. Sungkyu Kim (Northwestern Univ) ADMINI 2018.01.31 63
Notice 1/9 (Tue) Dr. Choon Won Byeon, ETRI ADMINI 2018.01.09 151
Notice 12/23 (Sat) Prof. Liangbing (Bing) Hu/Univ. of Maryland ADMINI 2017.12.22 186
Notice 2017 The Fall Semester Seminar ADMINI 2017.09.08 2681
230 10/10 (Tue) Dr. Joo Choi (POSCO) ADMINI 2017.09.29 2180
» 9/26 (Tue) Prof. Tae-Woo Lee (Seoul National University) ADMINI 2017.09.22 1083
228 9/19 (Tue) Representative Sang Min Lee (Congressman) ADMINI 2017.09.15 1181
227 9/12 (Tue) Monika Fleischer(Eberhard Karls University Tübingen) ADMINI 2017.09.14 786
226 9/12 (Tue) Prof. Pil Jin, Yoo (Sungkyunkwan Univ) ADMINI 2017.09.08 1313
225 9/11 (Mon) Won Joon, Cho (Lawrence Berkeley National Lab, Berkeley) ADMINI 2017.09.06 1321
224 9/13 (Wed) Dr. In Kyung Yoo (SAIT) ADMINI 2017.09.06 1546
223 8/24 (Tue) Prof. Jong Min Yuk (MSE KAIST) ADMINI 2017.08.24 1563
222 6/16 (Fri) Dr. Bok Yeop Ahn (Harvard University) ADMINI 2017.06.13 3117
221 6/12 (Mon) Prof. C. Suryanarayana (University of Central Florida) ADMINI 2017.06.05 1294
220 6/2 (fri) Robert M. Ulfig (CAMECA Instruments Inc) ADMINI 2017.06.01 1247
219 6/5 (Mon) Dr. Aron Varga/Dr. Andriy Lotnyk ADMINI 2017.05.30 1383
218 5/30 (Tue) Prof. Chang Hyeon Ko (Sookmyung Univ) ADMINI 2017.05.26 1457
217 5/23 (Tue) Prof. Don Hyeong Ha (Choongang university) ADMINI 2017.05.19 1087
216 5/16 (Tue) Prof. Eun Sun Cho (KAIST CBE) ADMINI 2017.05.10 1302
215 5/2 (Tue) Prof. Seung Woo Lee (SKKU) ADMINI 2017.04.28 1395
214 4/25 (Tue) Prof. Hyeong Sup Choi (Seoul National University of Science and Technology) ADMINI 2017.04.20 1222
213 4/11 (Tue) Prof. Kyeong Sook Choi (Eulji National University, Medical school) ADMINI 2017.04.07 1271
212 4/4 (Tue) Mrs. Eun Joo Jang (Samsung) ADMINI 2017.03.31 1412