Composition-Dependent Hot Carrier Relaxation Dynamics in Cesium Lead Halide (CsPbX3, X=Br and I) Perovskite Nanocrystals.
Cesium-based perovskite nanocrystals (NCs) have outstanding photophysical properties improving the performances of lighting devices. Fundamental studies on excitonic properties and hot-carrier dynamics in perovskite NCs further suggest that these materials show higher efficiencies compared to the bulk form of perovskites. However, the relaxation rates and pathways of hot-carriers are still being elucidated. By using ultrafast transient spectroscopy and calculating electronic band structures, we investigated the dependence of halide in Cs-based perovskite (CsPbX3with X=Br, I, or their mixtures) NCs on the hot-carrier relaxation processes. All samples exhibit ultrafast (<0.6 ps) hot-carrier relaxation dynamics with following order: CsPbBr3(310 fs)>CsPbBr1.5I1.5(380 fs)>CsPbI3NC (580 fs). These result accounts for a reduced light emission efficiency of CsPbI3NC compared to CsPbBr3NC.
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Heejae
0000-0001-5436-3753
H
Chung
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Seok Il
SI
Jung
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Hyo Jin
HJ
Kim
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Wonhee
0000-0002-7641-5718
W
Cha
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Eunji
E
Sim
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Dongho
0000-0001-8668-2644
D
Kim
Device Laboratory, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do, 16676, Republic of Korea.
Weon-Kyu
0000-0002-6913-4184
WK
Koh
School of Integrated Technology and Underwood International College, Yonsei University, Incheon, 21983, Republic of Korea.
Jiwon
0000-0002-1458-4743
J
Kim
electron densities; hot carriers; intraband relaxation; multiphonon emission; perovskites