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 페로브스카이트 나노결정은 뛰어난 광학적 특성으로 현재까지 회분식 반응기를 이용하여 핫인젝션, 재결정화 등의 다양한 방법으로 합성되어 왔다. 하지만, 현재 사용하는 회분식 반응기는 반응기 내부의 무작위 흐름 및 비활용영역의 존재로 인해 비효율적인 합성이 일어나고 이로 인해 화학 반응물간의 낮은 반응율과 미반응율의 낭비의 문제점이 있다. 그래서, 화학물간의 충돌을 높이고 합성 수율을 향상하기 위해 쿠에트-테일러 흐름에 관심을 가지게 되었다. 기존의 회분식 반응기의 무작위 흐름과는 다르게 쿠에트-테일러 흐름은 주기적이고 일정하다는 특징이 있고 이 흐름은 여러 실험적 조건을 조절함으로써 다양하게 조절할 수 있다. 이런 쿠에트-테일러의 흐름을 이용하여, 성공적으로 CsPbBr3 및 Cs4PbBr6 나노결정을 기존보다 각각 25.9%와 57%의 높은 수율로 합성할 수 있었다. 추가로, 짧은 반응시간 동안 얻은 반응 용액의 UV-vis 스펙트럼과 같은 광학적 결과를 분석하여 높아진 수율과 각 반응기에서 나온 서로 다른 결과에 대한 이유를 설명하기 위한 매커니즘도 밝힐 수 있었다. 

Due to their excellent photoelectric properties, the perovskite nanocrystals 
have been synthesized using various methods in batch reactor such as Hotinjection
method, reprecipitation method (also called supersaturated
reprecipitation, SR), ultrasonication method, solvothermal method and 
hydrogen-halide mediated method. However, stirred tank batch reactor (STBR) 
occurs inefficient synthesis because of random flow and dead-zone in a reactor 
so that the chemicals are unreacted with the low reaction rate and unreacted 
chemicals are wasted. So, we focused on the Couette-Taylor flow to promote 
the collision between chemicals in the reactor and improve reaction rate
through the unique flow. Unlike random turbulent eddy flow (RTEF) in a 
STBR, periodic Taylor vortex flow (PTVF) in a Couette-Taylor batch flow
(CTBR) has periodic and uniform flow fields. The flow fields can be 
controlled with various fields by manipulating the experimental conditions. 
Using the characteristic of Couette-Taylor flow, the nanocrystals of CsPbBr3
and Cs4PbBr6 were successfully synthesized with increased production yield 
25.9% and 57%, respectively. Moreover, we were able to elucidate the 
mechanism to demonstrate the reason of increased yield of nanocrystals using 
a CTBR and difference results of whole products using each reactor through 
the optical data analysis such as UV-vis spectra of reaction solution(crude 
solution) formed between short reaction time. 

Contents
1. Introduction
1.1. Perovskite nanocrystals..................................................................... 1
1.1.1 Structural formation of perovskite crystals..................................... 1
1.1.2 Optical properties of perovskite nanocrystals................................. 3
1.2 Synthesis method of the perovskite nanocrystals .............................. 6
1.3 Couette-Taylor flow......................................................................... 11
2. Materials and Methods
2.1. Materials ......................................................................................... 15
2.2. Experimental method...................................................................... 15
2.2.1. Preparation of cesium-oleate (Cs-OA) precursor ........................ 15
2.2.2. Preparation of PbBr2 precursor.................................................... 16
2.3. Synthesis of PNCs in the reactor .................................................... 16
2.3.1. Stirred tank batch reactor (STBR) ............................................... 16
2.3.2. Couette-Taylor batch reactor (CTBR).......................................... 17
2.4. Characterization .............................................................................. 17
3. Results and Discussion....................................................................... 19
3.1. Schematic of a STBR and CTBR.................................................... 19
3.2. Synthesis of perovskite nanocrystals............................................... 21
3.2.1. Synthesis PNCs under Cs-OA:PbBr2 = 1:1.25 molar ratio ............. 23
3.2.2. Synthesis PNCs under Cs-OA:PbBr2 = 1:3.76 molar ratio.............. 30
3.2.3. Mechanism of synthesis of PNCs................................................. 35
4. Conclusion........................................................................................... 40
References ............................................................................................... 42