Poster Sessions

2024 KPS Spring Meeting

Wednesday-Friday, November 4-6, 2020; Virtual Conference
Session P1-ap.4: Organic electronics and photonics
1:00 PM-1:50 PM, Thursday, November 05, 2020
Abstract: P1-ap.408* : Structural and Optical Characterization of Mechanochemically Synthesized Cs-based Perovskites
Baek Kyeong-Yoon
(Department of Physics and Astronomy, Seoul National University)

BAEK Kyeong-Yoon 1, LEE Woocheol 1, LEE Jeongjae 2, LEE Jonghoon 1, AHN Heebeom 1, KIM Junwoo 1, KANG Keehoon *1, LEE Takhee *1
(1Department of Physics and Astronomy, Seoul National University, 2School of Earth and Environmental Sciences, Seoul National University)
Over the past decade, lead halide perovskites (LHPs) have gained significant interest due to their attractive optoelectronic properties with photoconversion efficiency (PCE) exhibiting ca. 22% in perovskite solar-cell (PSC) technologies. Generally, solvent based synthesis has been utilized as a synthetic method of LHPs. Recently, mechanochemical synthesis (MCS) has emerged as an appealing alternative due to many distinctive advantages such as its solvent-free nature of the process. Even though precise mechanisms involved in MCS have not yet been fully elucidated, MCS enables a well-controlled environment where intermediate phases can be analyzed. In this study, we investigated the time-dependent behavior in the synthesis of Cs4PbBr6 (referred to as “0D perovskite”) by ball milling of stoichiometric precursor mixtures. During the synthesis process, we could identify the coexisting two additional phases: CsPb2Br5 and CsPbBr3, referred to as 2D and 3D phases, respectively, and derived the weight fraction of each phase from Rietveld refinement and NMR analysis. In addition, the peak photoluminescence (PL) intensity centered at 523 nm was observed to vary depending on the duration time of the synthesis and reached the maximum at around 3 hours of ball milling. The phase fraction analysis of the 0D powders with the maximum PL intensity indicates the presence of a finite amount of 3D phase, which agrees well with previous reports that proposed CsPbBr3 nanocrystals embedded in solution-synthesized Cs4PbBr6 microcrystals as the origin of a highly efficient green light with a PLQY of 90%. Our results provide a controllable synthetic methodology for acquiring 0D Cs-based perovskites with an efficient green emission through MCS and paves the way for developing high performance perovskite light emitting devices in the future.

Ball milling, Mechanochemical synthesis, Time-dependence, Cesium lead halide perovskite, Photoluminescence