Applications of Perylene Dyes in Agriculture and Industry: Development of High-Performance Spectrum conversion Film and TiO2?Perylene Dye Complex for Color Filters = 농업 및 산업 분야에서 퍼릴렌 염료의 응용: 고성능 광전환 필름 및 컬러 필터용 TiO₂-퍼릴렌 염료 복합체 개발

국문 초록 (Abstract)

페릴렌 기반 염료는 강한 가시광선 흡수, 높은 형광 양자 수율, 우수한 열적
및 광화학적 안정성을 바탕으로 첨단 농업 및 산업 분야에서 유망한 소재로
주목받고 있습니다. 그러나 고체 상태에서의 응집 유발 소광 (AggregationCaused Quenching, ACQ) 현상과 장시간 빛 노출에 따른 광분해 등의 문제로
인해, 스펙트럼 변환 필름(Spectrum Conversion Film, SCF)과 컬러 필터(Color
Filter) 등 실제 응용에는 한계가 존재합니다. 이에 본 연구는 농업용 적색
형광 SCF 와 산업용 디스플레이 컬러 필터라는 두 분야를 중심으로, 페릴렌
염료의 분자 설계, 합성 및 성능 최적화에 대한 전략을 제시하고, 각 응용에
적합한 물성 및 신뢰성 확보 방안을 탐구하였습니다. 농업 분야에서는 낭비되는 녹색광 (500–600 nm)을 적색광 (600–700 nm)으로
변환함으로써 식물의 광합성 효율 및 작물 생산성을 향상시킬 수 있는
SCF 가 주목받고 있습니다. 무기 및 유기 소재 모두 SCF 용으로
연구되었으나, 페릴렌 기반 유기 염료는 날카로운 흡수 대역과 높은 형광
효율로 특히 우수한 광학 특성을 나타냅니다. 본 연구에서는 베이(bay)
위치에 부피가 다른 입체 치환기를 도입함으로써 ACQ 를 억제하고 Stokes
shift 와 형광 양자 수율을 향상시킨 새로운 페릴렌 유도체를 설계하였습니다.
또한, 전자 밀도 재분포 및 기저 상태 (S₀)와 여기 상태 (S1) 간의 구조적
차이에 기반한 transition dipole moment (TDM) 분석을 통해 분자의 광물리적
특성을 정량적으로 해석하였습니다. 합성된 염료들 중 PBI-TBPO 는 가장
우수한 광학 특성과 ACQ 에 대한 내성을 보였으며, 이를 이용한 PMMA
기반 SCF 를 제작하여 실제 상추 재배 실험을 통해 식물 생장 및 광합성
향상 효과를 실증하였습니다.
산업 응용 측면에서는 페릴렌 염료가 높은 색순도와 광안정성을 요구하는
차세대 컬러 필터 기술의 유력 후보로서 주목받고 있습니다. 기존 안료 기반
컬러 필터는 내구성은 우수하나 색재현성이 떨어지고, 유기 염료는 색
특성은 뛰어나지만 광 및 열 안정성에서 취약점을 보입니다. 본 연구에서는
이러한 한계를 극복하기 위해 페릴렌 염료를 TiO2 나노입자에 흡착시킨
하이브리드 소재를 개발하였습니다. 일반적으로 광촉매 활성을 유도하는
TiO2 의 특성을 역이용하여, 적절한 조건에서 염료를 보호하고 광안정성과
열적 안정성을 개선할 수 있는 전략을 제시하였습니다. 또한 TiO2@염료 복합체 내 전자 거동 및 상호작용을 계산화학적 분석을 통해 정량적으로
규명하였으며, 이 복합체가 고신뢰성 컬러 필터 개발에 효과적으로 활용될
수 있음을 제시하였습니다.
2 장에서는 다양한 입체 치환기를 베이 위치에 도입한 페릴렌 유도체들을
합성하고, 이들의 흡광 및 발광 스펙트럼, frontier molecular orbital, TDM,
구조적 변화, ACQ 민감도 등을 포괄적으로 분석하였습니다. PBI-TBPO 는
가장 우수한 광특성과 ACQ 억제력을 나타냈으며, 이를 활용한 SCF 는
실질적인 농업적 효과를 나타냈습니다.
3 장에서는 TiO2 에 염료를 흡착시켜 광특성과 광안정성을 확보하는
하이브리드 전략을 적용하였으며, perylene, DPP, azo 염료의 광안정성,
열안정성 및 라디칼 생성 특성을 비교하였습니다. 페릴렌 기반 복합체가
가장 뛰어난 안정성을 보였으며, 광촉매 활성의 원인을 전자 밀도 재분포 및
TDM 을 통해 해석하였습니다.
4 장에서는 electron donating and withdrawing group 을 베이 및 오르토 위치에
도입한 네 종류의 새로운 페릴렌 염료를 설계·합성하고, 이들의 TiO2@염료
복합체 내에서의 전이 특성과 TDM 방향성, π-π 상호작용 변화 등을 계산 및
실험적으로 분석하였습니다. 그 결과, 치환기의 종류와 위치가 광흡수
특성과 광안정성에 결정적인 영향을 미친다는 사실을 규명하였으며, 이는
차세대 고성능 디스플레이용 컬러 필터 설계에 유의미한 지침을 제공할 수
있음을 보여주었습니다.

다국어 초록 (Multilingual Abstract)

Perylene dyes have emerged as promising candidates for advanced agricultural and industrial applications due to their strong visible-light absorption, high fluorescence quantum yields, and exceptional thermal and photochemical stability. Despite these advantages, their deployment in spectrum conversion films (SCFs) and color filters remains limited due to challenges such as aggregation-caused quenching (ACQ) in solid-state environments and photodegradation under extended light exposure. To address these limitations, this study investigates the rational design, synthesis, and performance optimization of perylene-based dyes, focusing on two distinct technological applications: red-fluorescent SCFs for agriculture and high-performance color filters for industrial displays.
In agricultural applications, red-fluorescent SCFs have been targeted for their ability to convert wasted green light into red light, thereby enhancing photosynthetic efficiency and crop productivity. While both inorganic and organic materials have been explored for SCFs, organic perylene-based dyes demonstrate significant potential due to their sharp absorption bands and high fluorescence efficiency. However, conventional red dyes used in SCFs often suffer from ACQ. This study introduces novel perylene derivatives designed with steric substituents to suppress ACQ and improve photophysical properties, enabling effective incorporation into SCFs. Furthermore, the practical agricultural impact was evaluated by cultivating lettuce under perylene-based SCFs for two weeks, with growth and photosynthetic performance compared to those grown under transparent films.
In industrial applications, perylene dyes have been explored for next-generation color filter technologies, where high optical sharpness and photostability are critical. Conventional pigment-based color filters are durable but lack color purity, while organic dyes exhibit sharp absorption but suffer from limited stability. To overcome these barriers, this research investigates the formation of hybrid materials by adsorbing perylene-based dyes onto TiO2 nanoparticles. This strategy influences the stabilizing properties of TiO2 to improve dye photostability and thermal resistance, facilitating the development of reliable and high-performance color filters for advanced display technologies. We also analyzed electron dynamics of TiO2@dye composite thoroughly.
In Chapter 2, a series of perylene-based dyes were synthesized for use in red-fluorescent spectrum conversion films (SCFs) by introducing substituents of varying steric volumes at the bay positions. These structural modifications were designed to tune the dyes’ photophysical behavior and improve their functional performance in film applications. Detailed analyses of absorption and emission spectra and frontier molecular orbitals were conducted. A clear trend was observed, where increasing the substituent bulkiness led to enhanced Stokes shifts and fluorescence quantum yields. These enhancements were attributed to greater electron density redistribution and structural change between the ground (S₀) and excited (S₁) states. To evaluate aggregation-caused quenching (ACQ), the molar volume, steric hindrance, and particle size of each dye were assessed. Among the synthesized dyes, the PBI-TBPO exhibited superior optical properties and resistance to ACQ. A PMMA-based SCF incorporating PBI-TBPO was fabricated and tested for its impact on agricultural efficiency. Measurements of lettuce's photosynthesis rates and growth demonstrated the practical potential of the dye in enhancing plant productivity under modified light conditions.
In Chapter 3, a hybrid material was developed by adsorbing dye molecules onto TiO2, a material traditionally known for promoting the photodegradation of organic compounds. This strategy was employed to improve the reliability of dyes used in color filters for CMOS image sensors and TV applications. Three dye molecules—perylene, diketopyrrolopyrrole (DPP), and azo-based compounds—were synthesized and systematically evaluated in both their powder and TiO2-complexed forms. Among them, the perylene-based hybrid material exhibited a notable enhancement in both photostability and thermal stability, whereas the DPP and azo-based hybrids showed contrasting behavior. Photophysical analyses and radical generation studies revealed that the extent of electron density redistribution within the dye molecules significantly affected photocatalytic activity and material degradation. Furthermore, an increase in TiO2 content led to improved thermal resistance across all samples, with the perylene hybrid showing the most pronounced improvement. This study highlights the structural and energetic factors influencing dye–TiO2 interactions and identifies the optimal dye candidate for producing reliable, high-performance color filter materials.
In Chapter 4, four novel perylene-based dyes were synthesized to enhance the optical performance and reliability of TiO2@dye hybrid materials for advanced color filter applications. Building on the previously studied PBI 2 framework, electron-donating (EDG) and electron-withdrawing groups (EWG) were introduced at the bay and ortho positions to modulate electronic characteristics and intermolecular interactions 1. The photophysical properties and stabilities of both the dyes and their corresponding hybrid materials were systematically evaluated. An integrated computational approach utilizing Materials Studio, Multiwfn, and Gaussian was employed to analyze molecular orbitals, transition dipole moment (TDM), and electron transfer behavior. Notably, the direction of TDM differed significantly between EDG- and EWG-substituted dyes, which in turn influenced the electron injection dynamics within the TiO2 complexes and altered their photocatalytic activity. The study also examined how variations in π–π stacking impacted the dyes’ molar extinction coefficients. EDG substitution was found to enhance the photostability of the hybrid materials, while ortho-substitution contributed to improved optical absorption characteristics. These results highlight the potential of the newly developed perylene-based TiO2 hybrids as high-performance color filter materials for next-generation display technologies.

목차 (Table of Contents)

• Abstract i
• List of tables ix
• List of figures x
• List of schemes xii
• Chapter 1 1
• Introduction 1
• 1.1 Introduction of Perylene Dyes 1
• 1.2 Perylene Dyes for Agricultural Applications 2
• 1.3 Perylene Dyes for Industrial Applications 3
• 1.4 Target Applications in Agriculture and Industry 5
• 1.5 TiO2-Mediated Photostability Enhancement: Solvent and Phase Considerations 6
• 1.6 Previous Studies on Perylene Dyes 6
• Chapter 2 8
• Effects of substituents on photophysical properties of perylene dyes for spectrum conversion film (SCF) 8
• 2.1 Introduction 8
• 2.2 Experimental section 10
• 2.2.1 Materials 10
• 2.2.2 Instruments 11
• 2.2.3 Fabrication of films 11
• 2.2.4 Computational calculations 11
• 2.2.5 Thermal stability test 12
• 2.2.6 Synthesis of compounds 12
• 2.2.7 Photosynthetic photon flux density (PPFD) measurement 15
• 2.2.8 Plant growth measurement 15
• 2.3 Results and discussion 16
• 2.3.1 Molecular design and analysis 16
• 2.3.1.1 Molecular design 16
• 2.3.1.2 Structural analysis of the compounds 17
• 2.3.2 Optical properties 18
• 2.3.2.1 Spectral properties 18
• 2.3.2.2 Stokes shift analysis 21
• 2.3.2.3 Fluorescence quantum yield (FQY) analysis 24
• 2.3.2.4 Thermal-stability test 27
• 2.3.2.5 Plant growth 28
• 2.4 Conclusion 29
• Chapter 3 31
• Enhancing the reliability of dyes for color filters through TiO2 adsorption: comprehensive identification of factors affecting photocatalysis 31
• 3.1 Introduction 31
• 3.2 Experimental section 33
• 3.2.1 Materials 33
• 3.2.1 Instruments 34
• 3.2.3 Fabrication of hybrid materials in films and solutions 35
• 3.2.4 Computational calculations 35
• 3.2.5 Photostability test 36
• 3.2.6 Particle size investigation 36
• 3.2.7 Electron spin resonance (ESR) 37
• 3.2.8 Thermal stability test 37
• 3.2.9 Synthesis of compounds 37
• 3.3 Results and discussion 41
• 3.3.1 Molecular design and synthesis 41
• 3.3.2 Geometry optimization of the molecules 42
• 3.3.2 Spectral properties 43
• 3.3.2.1. Optical properties of the dyes in the solution 43
• 3.3.3. Photostability test 44
• 3.3.3.1. Investigation of factors affecting photocatalysis 44
• 3.3.3.2. Photostability of dyes and hybrid materials in the film 46
• 3.3.3. Electron spin resonance (ESR) analysis 48
• 3.3.4. Electron transfer investigation 50
• 3.3.4.1. Electronic feasibility analysis 50
• 3.3.4.2. Transition dipole moment (TDM) analysis 51
• 3.3.4.3. Computational calculation of the hybrid materials 53
• 3.3.4.4. Light scattering and screening effect analysis of TiO2 54
• 3.4. Thermal stability 55
• 3.4.1. Thermal stability of dyes in powder 55
• 3.4.2. Thermal stability of hybrid materials in film 56
• 3.4 Conclusion 58
• Chapter 4 60
• Novel Perylene Dye–TiO2 Hybrid materials: A Computational and Experimental Insight into Improving Color Filter Materials in Next-Gen Displays 60
• 4.1 Introduction 60
• 4.2 Experimental section 62
• 4.2.1 Materials 62
• 4.2.2 Instruments 62
• 4.2.3 Fabrication of hybrid materials in films 63
• 4.2.4 Computational calculations 63
• 4.2.5 Electron spin resonance (ESR) analysis and photo and thermal stability tests 64
• 4.2.6 Synthesis of compounds 65
• 4.3 Results and discussion 68
• 4.3.1 Molecular design 68
• 4.3.2 Geometry analysis of the dyes 70
• 4.3.3 Computational analysis of the materials 72
• 4.3.4 Computational analysis of the hybrid materials. 75
• 4.3.5 Electron Spin Resonance (ESR) analysis 78
• 4.3.6 Photostability test 80
• 4.3.7 Thermal stability analysis 82
• 4.3.8 Spectral properties 84
• 4.3.8.1 Optical properties of the dyes in the solution 84
• 4.3.8.2 Optical properties of the hybrid materials in the film 86
• 4.4 Conclusion 87
• References 89
• 초 록 97