119th General Meeting of the KCS

Type Poster Presentation
Area 물리화학
Room No. 포스터발표장
Time 4월 20일 (목요일) 11:00~12:30
Code PHYS.P-37
Subject Composition-dependent quantum-confined Stark effect in lead bromide perovskite nanocrystals
Authors 함수진, 정희재, 김동호*
연세대학교 화학과, Korea
Abstract We present a study the origin of the emission linewidths broadening observed for lead bromide (APbBr3, A = CH3NH3 and Cs) perovskite nanocrystals (NCs). Our analysis is based on a statistically significant number of nanocrystal spectra and defocused images measured by confocal and wide-field microscopy, respectively. Based on this observation, we explain the particular susceptibility of CH3NH3PbBr3 NCs to spectral diffusion causing the linewidth broadening via the linear quantum-confined Stark effect. After laser excitation and exciton formation, an electron or hole from the exciton localizes near the surface of the NC leaving a delocalized charge carrier inside the NC core. Following this initial charge localization or ionization, the delocalized charge carrier can also be localized leading to a net neutral NC core. If the NC environment is decorated by charges following previous process, then after subsequent ionization, a charge localized in the NC’s environment can relax back into the NC core recombining with the delocalized charge carrier. These mechanisms would create, if not alter, a surface dipole and lead to a net change in the local electric field. The single NC spectra express this change as a large Stark shift in the emission frequency. This comparative investigation of CH3NH3PbBr3 and CsPbBr3 NCs enable us to understanding the relationship between polarity of NC and emission linewidths broadening of lead bromide perovskite nanocrystals.
E-mail realfn@yonsei.ac.kr