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光伏电池的分类及其特点光伏电池作为一种将太阳能转化为电能的装置，被广泛应用于各个领域。
根据不同的制作材料和工艺，光伏电池可以分为多种类型，每种类型都有其独特的特点和应用场景。
本文将对光伏电池的分类及其特点进行详细介绍。
一、单晶硅太阳能电池单晶硅太阳能电池是目前应用最广泛的光伏电池之一。
其制作工艺复杂，需采用单晶硅片制成。
单晶硅太阳能电池具有高转换效率、较长的使用寿命和良好的稳定性等特点，是供电效果最佳的一种太阳能电池。
此外，单晶硅太阳能电池较为适用于能量密集型的应用场景，如家庭光伏发电系统和工业用途。
二、多晶硅太阳能电池多晶硅太阳能电池是另一种常见的光伏电池类型。
相较于单晶硅太阳能电池，多晶硅太阳能电池的制作工艺相对简单，成本较低。
多晶硅太阳能电池的转换效率较单晶硅太阳能电池略低，但在大面积光伏发电场所的应用中，多晶硅太阳能电池具有较大的优势。
此外，多晶硅太阳能电池可通过拼接多块硅片来增加输出功率，适用于大规模光伏发电项目。
三、薄膜太阳能电池薄膜太阳能电池采用非晶态硅或其他半导体材料制成薄膜，并直接将其吸附在光伏电池基板上。
薄膜太阳能电池具有制作工艺简单、重量轻、柔性强等特点，可以更好地适应不规则曲面的安装环境。
然而，薄膜太阳能电池的转换效率相对较低，且衰减速度较快，适用于对成本和可塑性要求较高的应用场合，如建筑物外墙、可穿戴设备等领域。
四、有机光伏电池有机光伏电池采用有机高分子材料制成，具有低成本、制造工艺简单和可大面积生产的优势。
然而，有机光伏电池的转换效率相对较低，稳定性较差，寿命短暂。
目前，有机光伏电池主要应用于低功率设备和可穿戴电子产品。
五、其他类型光伏电池除了以上常见类型的光伏电池，还有许多其他类型的光伏电池正在被研究和开发。
例如，染料敏化太阳能电池利用染料吸收光能，并间接将其转化为电能；钙钛矿太阳能电池采用钙钛矿结构的材料制成，具有高效率和低制造成本的优势。
这些新型光伏电池类型在转换效率、稳定性和可制造性方面都有不同程度的突破和发展。
光伏组件的分类及用途：
1.第一代：硅基光伏组件，主要包括单晶硅、多晶硅及非晶硅光伏组件。
这类组件技
术相对成熟，是较早实现商业化应用的一类光伏组件，目前有着较大的市场占有率。
随着材料加工工艺的改进及组件封装技术的更新，这类组件的光电转换效率仍在不断提高，目前其实验室效率可以达到25%以上，同时生产成本也逐渐降低。
2.第二代：多元化合物薄膜光伏组件，主要包括碲化镉(CdTe)、砷化镓(GaAs)、铜铟镓
硒(CIGS)等光伏组件。
这类光伏组件具有消耗材料少、制备能耗低、光电转换效率较高、重量轻、衰减率低、适合与建筑结合(BIPV)等优点，是目前业界看好的一类光伏组件。
3.第三代：新型光伏组件，主要包括钙钛矿光伏组件、染料敏化光伏组件、量子点光
伏组件、有机光伏组件等。
这类组件具有成本较低、工艺较简单的特点，转换效率也在不断提升。
目前正在实验室研发阶段和部分量产阶段，有着较大的发展潜力和较好的应用前景。
有机-无机金属卤化物钙钛矿
有机-无机金属卤化物钙钛矿是由有机阳离子和无机阴离子组成
的混合物，其中最常见的有机阳离子是甲基铵(CH3NH3+)，而无机阴
离子则通常是卤化物离子（如Cl-、Br-、I-）。
这种结构的材料具
有良好的光吸收特性和电荷传输性能，使其成为太阳能电池领域备
受瞩目的材料。
有机-无机金属卤化物钙钛矿太阳能电池的制备工艺相对简单，
成本较低，因此备受关注。
通过调控材料的结构和组分，可以实现
更高的光电转换效率和更长的使用寿命。
与传统的硅基太阳能电池
相比，有机-无机金属卤化物钙钛矿太阳能电池在光电转换效率和制
备成本上具有明显优势。
然而，有机-无机金属卤化物钙钛矿太阳能电池也面临着一些挑战，例如材料的稳定性和环境适应性等问题。
研究人员正在不断努
力解决这些问题，以推动该材料在太阳能电池领域的应用。
总的来说，有机-无机金属卤化物钙钛矿作为一种新型光伏材料，具有巨大的潜力。
随着对该材料的深入研究和技术的不断进步，相
信它将在未来的太阳能电池领域发挥重要作用。
三甲基铝在光伏产业的应用
三甲基铝（trimethylaluminum）是一种有机金属化合物，广泛
应用于光伏产业中。
以下是三甲基铝在光伏产业中的主要应用：
1. 光伏薄膜沉积：三甲基铝可用作一种前体材料，用于光伏薄膜沉积过程中的化学气相沉积（CVD）或物理气相沉积（PVD）。
它可以提供易于分解的铝源，并在光伏材料表面
沉积均匀的薄膜。
2. 光伏电池制造：三甲基铝可用于制造光伏电池的阳极材料。
它可以作为一种高纯度的金属有机前体，通过CVD或热蒸发
等方法将铝层沉积在电池的阳极上，提供导电性和稳定性。
3. 填孔层材料：在光伏电池的制造过程中，三甲基铝可以用作填孔层材料，填补电池背面金属的间隙，提高电池的光电转换效率。
4. 清洗剂：三甲基铝在光伏产业中还可用作清洗剂，用于清洗光伏电池的表面。
它可以去除可能污染电池表面的有机或无机残留物，并提高电池的表面质量和性能。
总的来说，三甲基铝在光伏产业中的应用主要涉及光伏薄膜沉积、阳极材料制备、填孔层材料和清洗剂等方面，为光伏产业提供了重要的材料支持和技术增益。
光伏组件的主要材料-回复光伏组件是利用光电效应将太阳能转化为电能的装置。
它由多个关键材料组成，每个材料都在太阳能转换和电能产生中扮演着重要的角色。
本文将逐步回答关于光伏组件的主要材料的问题，详细介绍它们的特性、应用和未来发展趋势。
一、硅：光伏组件的主要材料之一是硅。
硅是一种半导体材料，具有优良的光电转换性能。
它主要通过锗和砷等掺杂剂来改变其导电性质。
硅可以分为单晶硅、多晶硅和非晶硅三种类型。
单晶硅具有最高的转换效率，但成本较高。
多晶硅则更为常见，成本较低，但相对效率略低。
非晶硅是最便宜的，但也是最低效的。
硅材料的稳定性、可靠性和长寿命是其在光伏行业中被广泛使用的重要原因之一。
二、硒化铟：硒化铟是一种II-VI族化合物，具有较高的吸光度和光电转换效率。
硒化铟可以作为薄膜太阳能电池的光敏材料。
相对于硅，硒化铟可以在更薄的层次上吸收更多的光线，并将其转化为电能。
硒化铟光伏组件具有高度可定制性和灵活性，可以生产出各种形状和尺寸的光伏设备。
三、砷化镓：砷化镓是一种III-V族化合物，也是一种重要的光伏材料。
砷化镓具有优异的光电特性，其能带结构使之能够在更高频率的光谱范围内吸收光线。
它的光电转换效率高，适用于特定的光伏应用，如航空航天和军事领域。
尽管砷化镓是昂贵的材料，但由于其高效率和可靠性，它仍然是一种可行的选择。
四、碲化铟镉：碲化铟镉是一种II-VI族化合物，也是光伏组件中常用的材料之一。
碲化铟镉具有较高的吸光度和较高的光电转换效率。
它在光谱范围内的光吸收性能非常高，能够实现较高的转换效率。
然而，由于镉的环境污染风险，碲化铟镉在某些地区的使用受到限制。
除了上述材料外，还有许多其他材料在光伏组件中得到应用。
例如，有机材料（如聚合物）和钙钛矿等新型材料被广泛研究和开发，以改善光伏组件的性能和降低成本。
未来，随着对可再生能源需求的不断增长，光伏技术将不断发展，并且新的材料将会被发现和应用于光伏组件中。
人们将继续寻求更高效率、更持久、更环保以及生产成本更低的光伏材料。
光伏材料的研究及其在新能源开发中的应用光伏材料是指能够将太阳能转化为电能的材料，近年来，随着对能源可持续发展问题的日益重视，光伏材料的研究和开发逐渐成为一个热门领域。
本文将探讨光伏材料的研究发展、应用现状及其在新能源开发中的作用。
一、光伏材料研究发展光伏材料的发展始于20世纪50年代，当时，单晶硅被发现具有光电转换的能力，成为了最早应用于光伏电池制造的材料之一。
目前，光伏材料种类繁多，包括单晶硅、多晶硅、铜铟镓硒等无机材料以及聚合物、碳纳米管等有机材料，这些材料的性能和应用场景也不尽相同。
以单晶硅为例，它的电子结构和物理特性决定了其在光伏电池中的重要地位。
单晶硅能够实现高电子迁移率和长寿命，因此其在太阳能电池的效率、可靠性、使用寿命等方面都有着较为优异的表现。
但是单晶硅的制造成本和能源消耗很高，这也成为了其应用受限的主要因素。
铜铟镓硒材料则因具有优异的光吸收特性、高效能转换率、稳定性等优点，被认为是光伏材料的前途所在。
相较于单晶硅，其制造成本更低且能源消耗更少，且可以应用于大量生产。
不过，铜铟镓硒材料也存在着发电效率低、生产工艺难、资源富集不足等问题。
二、光伏材料在新能源开发中的应用光伏材料的应用已经不再局限于传统的太阳能电池，而是逐渐拓展到更广泛的领域。
下面从几个方面阐述光伏材料在新能源开发中的应用。
1. 太阳能光伏电池太阳能光伏电池是光伏材料的主要应用领域。
传统的太阳能电池使用单晶硅等无机材料作为基础材料，通过光电转换将太阳能转化为电能。
近年来，随着新型光伏材料不断推出，太阳能光伏电池的效率和稳定性也在不断提高，促进了太阳能发电技术的发展。
2. 储能系统光伏材料在储能系统中也有着广泛的应用。
光伏发电系统通过光电转换将太阳能转化为电能，将多余的电能储存在电池中，在需要时进行调用。
由于太阳能发电存在着波动性，因此储能系统对能源的稳定供应起着重要作用。
铅酸蓄电池、锂离子电池等大量储能系统选择使用光伏材料进行电池制造，以提高电池的效率和稳定性。
太阳能电池中有机聚合物材料的研究应用一、概述太阳能电池是一种将光能转化为电能的装置，其中有机聚合物材料作为一种新型的太阳能电池材料，吸引了广泛的关注和研究。
有机聚合物材料具有易制备、可塑性好、成本低等优点，因此在太阳能电池中应用具有广阔的前景。
二、有机聚合物材料的介绍有机聚合物材料是指由有机分子通过化学键链接而成的大分子材料。
这种材料具有很多有用的性质，如可塑性好、易加工、低成本、轻质等。
因此，在太阳能电池中应用具有广泛的前景。
三、有机聚合物材料在太阳能电池中的应用有机聚合物材料在太阳能电池中的应用主要表现在以下几个方面：1. 有机太阳能电池有机太阳能电池是一种利用有机聚合物薄膜作为太阳能电池的光伏材料的一种设备。
与传统的硅基太阳能电池相比，有机太阳能电池具有更便宜的制造成本、柔性和轻质等特点。
2. 透明有机太阳能电池透明有机太阳能电池是一种开发成为透明的有机聚合物薄膜太阳能电池的光伏设备。
这种透明太阳能电池可以应用在诸如机动车、建筑物和移动设备等领域，能够在不影响外观的情况下向内供电。
3. 有机-无机混合太阳能电池有机-无机混合太阳能电池是一种将有机聚合物与无机半导体材料混合的太阳能电池。
这种混合太阳能电池具有兼顾两种材料优点的特点，既具有有机聚合物的可塑性、易加工、低成本等特点，也具有无机半导体的良好电子传输性能等特点。
四、有机聚合物材料应用的优点1. 成本低有机聚合物材料的制备成本相对较低，大大降低了太阳能电池的制造成本。
2. 可塑性好有机聚合物材料具有非常好的可塑性，可以通过各种加工工艺制成各种形式的太阳能电池。
3. 良好的光学性能有机聚合物材料具有良好的光学性能，能够将太阳光转化为电能的效率提高。
五、有机聚合物材料应用的瓶颈1. 效率低当前有机聚合物材料太阳能电池的转换效率仍然比较低，限制了其在大规模应用中的发展。
2. 稳定性差有机聚合物材料的稳定性不如无机半导体太阳能电池，可能会影响太阳能电池的寿命和稳定性。
有机光电材料的性能表征与优化有机光电材料是一类具有广泛应用前景的材料，其优异的光学和电学性能使其在太阳能电池、有机发光二极管等光电器件中具有重要作用。
为了充分发挥有机光电材料的性能，需要对其进行详细的性能表征和优化。
本文旨在探讨有机光电材料的性能表征方法并介绍优化策略。
一、性能表征方法在对有机光电材料的性能进行表征时，需要考虑其光学和电学性能等方面的参数。
以下是常用的性能表征方法：1. 光学性能表征有机光电材料的吸收谱和发射谱是其光学性能的关键指标。
紫外可见吸收光谱可以揭示材料的吸光度、带隙宽度等信息，荧光发射光谱可以反映材料的发光效率和光谱特性。
此外，还可以通过荧光寿命和量子产率等参数来评估材料的光学性能。
2. 电学性能表征有机光电材料在电学方面的性能主要包括载流子迁移率、载流子寿命、电子亲和势等指标。
载流子迁移率可以反映材料的电导率和电子传输能力，载流子寿命则与材料的电子复合速率相关。
通过电学性能表征，可以评估材料在光电器件中的可用性和稳定性。
3. 动态性能表征除了静态性能的表征之外，了解有机光电材料的动态响应特性也是十分重要的。
例如，对于光电二极管材料，可以通过研究其响应时间、内外量子效率和电流电压关系等参数来评估其动态性能。
4. 表面形貌表征有机光电材料的表面形貌对其性能具有重要影响。
通过扫描电子显微镜（SEM）和原子力显微镜（AFM）等手段可以观察材料的表面形态和颗粒分布情况，进而评估其性能优劣。
二、性能优化策略为了提高有机光电材料的性能，可以采取以下优化策略：1. 分子结构调控通过有针对性地设计和合成有机光电材料的分子结构，可以改变其光电性能。
例如，通过引入不同的官能团或调整分子链的长度，可以调控材料的光谱特性、电荷传输能力等。
2. 杂化结构设计将有机光电材料与无机材料进行结合，构建复合结构，可以充分利用两者的优点。
例如，可通过有机-无机杂化材料构建高效率的光伏器件，融合有机材料的可塑性和无机材料的稳定性。
光伏薄膜原材料
光伏薄膜的原材料主要包括以下几种：
1.硅：硅是光伏薄膜的主要原材料，通常使用单晶硅、多晶硅或非晶硅。
硅可以转化太阳能光线为电能，然后输送到电池组件。
2.透明导电氧化物（TCO）：TCO用作光伏薄膜的导电层，常见的TCO材料包括氧化锡掺杂的铟锡氧化物（ITO）和氧化锌（ZnO）。
3.与硅基底材相比，有机薄膜太阳能电池材料更容易制备，并且具有较低的成本，因此也被广泛研究。
有机薄膜太阳能材料包括聚合物、碳化物和非全合成材料等。
4.其他功能性材料：包括光伏薄膜中的光吸收层、电子传输材料和保护层等。
常见的光伏薄膜材料包括氧化物、纳米颗粒、二氧化钛、铜铟镓硒（CIGS）等。
这些原材料通常被使用在光伏薄膜制备的过程中，通过不同的技术和工艺组合，形成能够将太阳能转化为电能的薄膜材料。
Synthesis and photophysical properties of structural isomers of novel 2,10-disubstituted benzofuro[2,3-e ]naphthoxazole-type fluorescent dyesHaruka Egawa Ooyama a ,*,Yousuke Ooyama b ,Toshihiko Hino a ,Takehiro Sakamoto a ,Takahiro Yamaguchi b ,Katsuhira Yoshida a ,b ,*a Department of Applied Science,Graduate School of Integrated Arts and Science,Kochi University,Akebono-cho,Kochi 780-8520,Japan bDepartment of Applied Science,Faculty of Science,Kochi University,Japana r t i c l e i n f oArticle history:Received 10December 2010Received in revised form 26March 2011Accepted 30March 2011Available online 13April 2011Keywords:Fluorescent dyePhotophysical property Substituent effectSolid-state fluorescence Crystal structure Structual isomersa b s t r a c tStructural isomers of novel 2,10-disubstituted benzofuro[2,3-e ]naphthoxazole fluorescent dyes have been synthesized.The phtophysical properties have been investigated in solution and in the solid state.The absorption and fluorescence intensities of the naphth[1,2-d ]oxazoles are much stronger than those of the naphth[2,1-d ]oxazoles in solution.Moreover,in the solid state,the emission intensities of the former are typically much stronger than those of latter isomers.To understand the differences in pho-tophysical properties,semi-empirical molecular orbital calculations and the X-ray crystallographic analyses have been performed.Ó2011Elsevier Ltd.All rights reserved.1.IntroductionBenzoxazole derivatives have received considerable attention because of important applications as laser dyes,organic scintilla-tors,and UV dyes in the optoelectronic industry [1e 4]and as antibacterial agents,HIV protease inhibitors,and antitumor agents in medicine [5e 9].In particular,intense absorption and emission properties of benzooxazole-type dyes are very useful as organic sensitizers for dye-sensitized solar cells and as emitters for organic electroluminescence devices [10e 15].Recently,Ooyama et al .have reported that a novel asymmetric heterocyclic o -quinone,3-dibu-tylamino-8H -5-oxa-8-aza-indeno[2,1-c ]fluorene-6,7-dione was allowed to react with p -cyanobenzaldehyde to give the structural isomers of the novel benzofuro[2,3-c ]oxazolo[4,5-a ]carbazole-type (1)and benzofuro[2,3-c ]oxazolo[5,4-a ]carbazole-type (2)fluo-rophores which differ in the position of oxygen and nitrogen atoms of the oxazole ring (Fig.1)[16,17].In a previous study,we reported the novel asymmetric heterocyclic o -quinones,9-dibutylamino-benzo[b ]naphtho[1,2-d ]furan-5,6-dione (3)can be prepared by the reaction of sodium 1,2-naphthoquinone-4-sulphonate with m -dibutylaminophenol [18].In this present study,we designed and synthesized the structural isomers of novel 2,10-disubstituted benzofuro[2,3-e ]naphth [1,2-d ]oxazole-type (4)and 2,10-disubsti-tuted benzofuro[2,3-e ]naphth[2,1-d ]oxazole-type (5)fluorophores with various substituents conjugated to the chromophore skele-tons which were derived from the condensation reaction of 3with various arylaldehydes in the presence of ammonium acetate as the nitrogen source.The photophysical properties of these isomers 4and 5in solution and in the crystalline state were investigated.To understand the differences in photophysical properties between the structural isomers and the dramatic substituent effects on the photophysical properties,semi-empirical molecular orbital calcu-lations (AM1and INDO/S)and X-ray crystallographic analyses were performed.On the basis of these results,relationships between the observed photophysical properties and the chemical and crystal structures of these isomeric fluorophores are discussed.2.ExperimentalMelting points were determined on Rigaku Thermo Plus 2system TG8120.IR spectra were recorded on a JASCO FT/IR-5300spectrometer for sample in KBr pellet form.Absorption spectra were observed with a JASCO UV-670spectrophotometer and*Corresponding authors.Tel.:þ81888448296;fax:þ81888448359.E-mail address:kyoshida@kochi-u.ac.jp (K.Yoshida).Contents lists available at ScienceDirectDyes and Pigmentsjournal homepage:w ww.else/locate/dyepig0143-7208/$e see front matter Ó2011Elsevier Ltd.All rights reserved.doi:10.1016/j.dyepig.2011.03.031Dyes and Pigments 91(2011)481e 488fluorescence spectra were measured with a JASCO FP-6600spec-trophotometer.The fluorescence quantum yields (F )of solutions and the crystals were determined by a Hamamatsu C9920-12by using a calibrated integrating sphere.Elemental analyses were recorded on a Perkin Elmer 2400ⅡCHN analyzer.1H and 13C NMR spectra were recorded on a JNM-LA-400(400,100MHz)FT NMR spectrometer with tetramethylsilane (TMS)as an internal standard.Column chromatography was performed on silica gel (KANTO CHEMICAL,60N,spherical,neutral).2-(4-carboxyphenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth [1,2-d ]oxazole (4a ’)and 2-(4-carboxy phenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth[2,1-d ]oxazole (5a ’):A solution of 3(2.00g,5.32mmol),p -carboxybenzaldehyde (0.96g, 6.38mmol),and ammonium acetate (8.22g,107mmol)in acetic acid (30mL)was stirred at 90 C for 1h.The reaction mixture poured into cold water,causing the precipitate and then filtered.The resulting residue was washed with CH 2Cl 2to give the mixture of 4b ’and 5b ’(2.67g,quant.)as a yellow powder which was used directly in subsequent reactions.2-(4-butoxycarbonylphenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth[1,2-d ]oxazole (4a)and 2-(4-butoxycarbonylphenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth[2,1-d ]oxazole (5a):A solu-tion of the mixture of 4a ’and 5a ’(0.40g,0.79mmol),butyl iodide (0.27g,1.48mmol),and Na 2CO 3(0.20g,1.87mmol)in DMF (20mL)was stirred at 100 C for 10h.The reaction mixture poured into cold water,causing the precipitate and then filtered.The resulting residue was extracted with CH 2Cl 2,and washed with water.The organic extract was evaporated.The residue was chromatographed on silica gel (toluene :acetic acid ¼10:1as eluent)to give 4a (0.37g,yield 84%)as a yellow powder and 5a (0.03g,yield 1%)as a yellow powder.Compound 4a:M.p.176.6 C;1H NMR (400MHz,[D 3]chloroform,TMS):d ¼0.99e 1.04(m,9H),1.44(tq,4H),1.53(tq,4H),1.68(tt,2H),1.81(tt,2H),3.40(t,4H),4.39(t,2H),6.85(dd,J ¼8.80,2.20Hz,1H),6.97(d,J ¼2.20Hz,1H),7.71(m,2H),8.17(d,J ¼8.80Hz,1H),8.22(d,J ¼8.80Hz,2H),8.44(d,J ¼8.80Hz,2H),8.62(d,J ¼7.08Hz,1H),8.71(dd,J ¼7.60,1.20Hz,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼13.79,14.04,19.29,20.38,29.34,30.77,51.34,65.20,94.13,109.44,113.30,118.70,122.04,123.37,123,38,123.59,124.19,125.16,126.14,126.29,127.00,130.09,131.04,132.20,137.15,138.06,147.88,159.06,160.42,166.04;IR (KBr):n ¼1713cm À1;elemental analysis calcd (%)for C 36H 38N 2O 4:C 76.84,H 6.81,N 4.98;found:C 77.14,H 6.97,N 5.10.Compound 5a:M.p.172.1 C;1H NMR (400MHz,[D 3]chloroform,TMS):d ¼1.02(m,9H),1.43(tq,J ¼7.32Hz,4H),1.53(tq,J ¼7.32Hz,2H),1.66(tt,J ¼7.32Hz,4H),1.81(tt,J ¼6.60Hz,2H),3.40(t,J ¼7.32Hz,4H),4.39(t,J ¼6.60Hz,2H),6.85(dd,J ¼8.80,2.20Hz,1H),7.00(d,J ¼2.20Hz,1H),7.66(dd,J ¼8.00Hz,1H),7.72(dd,J ¼8.00Hz,1H),8.15(d,J ¼8.00Hz,1H),8.23(d,J ¼8.00Hz,2H),8.43(d,J ¼8.00Hz,1H),8.48(d,J ¼8.00Hz,2H),8.63(d,J ¼8.00Hz,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼13.79,14.03,19.29,20.38,29.32,30.76,51.34,65.21,94.59,109.18,113.37,116.50,117.46,121.39,121.57,124.42,124.80,126.43,126.52,127.18,127.62,130.08,130.95,132.50,143.66,146.41,147.51,158.80,161.73,165.98;IR (KBr):n ¼1719cm À1;elemental analysis calcd (%)for C 36H 38N 2O 4:C 76.84,H 6.81,N 4.98;found:C 76.72,H 6.80,N 4.99.2-[4-(2,3,4,5,6-penta fluorobenzoxy)carbonylphenyl]-10-dibu-tylamino-benzofuro[2,3-e ]naphth[1,2-d ]oxazole (4b):A solution of the mixture of 4a ’and 5a ’(2.00g,3.95mmol),penta fluorobenzyl bromide (1.93g,7.40mmol),and Na 2CO 3(0.99g,9.38mmol)in DMF (15mL)was stirred at 100 C for 4h.The reaction mixture poured into cold water,causing the precipitate and then filtered.The resulting residue was extracted with CH 2Cl 2,and washed with water.The organic extract was evaporated.The residue was chro-matographed on silica gel (CH 2Cl 2as eluent)to give 4b (2.02g,yield 75%)as a yellow powder.Compound 4b:M.p.191.2 C;1H NMR (400MHz,[D 3]chloroform,TMS):d ¼1.01(t,J ¼8.00Hz,6H),1.44(tq,J ¼8.00Hz,4H),1.68(tt,J ¼8.00Hz,4H),3.41(t,J ¼8.00Hz,4H),5.51(s,2H),6.86(dd,J ¼8.80,2.40Hz,1H),6.97(d,J ¼2.40Hz,1H),7.71(m,2H),8.19(d,J ¼8.00Hz,2H),8.44(d,J ¼8.00Hz,2H),8.62(d,J ¼8.80Hz,1H),8.71(d,J ¼8.80Hz,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼14.03,20.39,29.34,51.34,94.11,109.48,113.25,118.86,122.06,123.36,123.59,123.60,124.20,124.22,125.21,125.22,126.20,126.31,127.08,130.33,130.34,130.74,131.63,131.64,135.74,137.13,137.99,147.93,159.09,160.13,165.24;IR (KBr):n ¼1720cm À1;elemental analysis calcd (%)for C 39H 31N 2O 4F 5:C 68.22,H 4.55,N 4.08;found:C 68.26,H 4.76,N 4.02.2-(9-anthryl)-10-dibutylamino-benzofuro[2,3-e ]naphth[1,2-d ]oxazole (4c)and 2-(9-anthryl)-10-dibutyl amino-benzofuro[2,3-e ]naphth[2,1-d ]oxazole (5c):A solution of 3(1.00g,2.66mmol),9-anthraldehyde (0.82g,4.00mmol),and ammonium acetate (4.11g,53mmol)in acetic acid (60mL)was stirred at 90 C for 2h.After concentrating under reduced pressure,the resulting residue was dissolved in CH 2Cl 2,and washed with water.The organic extract was evaporated.The residue was chromatographed on silica gel (xylene :acetic acid ¼20:1as eluent)to give 4c (0.46g,yield 31%)as a red powder and 5c (0.33g,yield 22%)as an orange pound 4c:M.p.112e 114 C;1H NMR (400MHz,[D 6]acetone,TMS):d ¼1.00(t,J ¼7.32Hz,6H),1.42e 1.51(m,4H),1.67e 1.75(m,4H),3.51(t,J ¼7.56Hz,4H),7.03(dd,J ¼8.80,1.70Hz,1H),7.09(d,J ¼2.20Hz,1H),7.63e 7.67(m,4H),7.78e 7.87(m,2H),8.27e 8.30(m,4H),8.40(d,J ¼8.80Hz,1H),8.76(d,J ¼8.04Hz,1H),8.86(d,J ¼8.56Hz,1H),8.95(s,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼14.03,20.38,29.35,51.33,94.29,109.46,113.44,118.33,121.24,122.08,123.54,123.72,124.22,125.19,125.55,125.75,126.09,126.30,127.39,128.64,130.76,131.15,131.66,136.21,136.74,138.46,147.86,159.07,160.23;IR (KBr):n ¼1506,1632cm À1;elemental analysis calcd (%)for C 39H 34N 2O 2:C 83.24,H 6.09,N 4.98;found:C 83.21,H 6.13,N 4.85.Compound 5c:M.p.174e 176 C;1H NMR (400MHz,[D 6]acetone,TMS):d ¼1.02(t,J ¼7.32Hz,6H),1.43e 1.55(m,4H),1.69e 1.77(m,4H),3.52(t,J ¼7.56Hz,4H),7.02(dd,J ¼8.80,2.44Hz,1H),7.14(d,J ¼2.20Hz 1H),7.63e 7.67(m,4H),7.72e 7.76(m,1H),7.83e 7.87(m,1H),8.25e 8.30(m,4H),8.38(d,J ¼9.04Hz,1H),8.44(d,J ¼8.04Hz,1H),8.87(d,J ¼8.32Hz,1H),8.96(s,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼14.04,20.40,29.37,51.36,94.77,109.24,113.60,116.40,117.68,121.32,121.64,124.42,124.81,125.57,125.58,125.81,125.82,126.34,126.50,127.37,128.62,130.83,131.13,131.57,144.05,146.92,147.54,158.89,161.67;IR (KBr):n ¼1507,1634cm À1;elemental analysis calcd (%)for C 39H 34N 2O 2:C 83.24,H 6.09,N 4.98;found:C 83.41,H 6.19,N 4.87.1-(1-pyrenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth[1,2-d ]oxazole (4d)and 2-(1-pyrenyl)-10-dibutyl amino-benzofuro[2,3-e ]naphth[2,1-d ]oxazole (5d):A solution of 3(1.00g,2.66mmol),N OONR NBu 2CN O NONR NBu 2CN21Fig.1.Ooyama et al.have reported novel benzofuro[2,3-c ]oxazolo[4,5-a ]carbazole-type (1)and benzofuro[2,3-c ]oxazolo[5,4-a ]carbazole-type (2)fluorophores.H.E.Ooyama et al./Dyes and Pigments 91(2011)481e 4884821-pyrencarbaldehyde(0.92g,4.00mmol),and ammonium acetate (4.11g,53mmol)in acetic acid(60mL)was stirred at90 C for2h. After concentrating under reduced pressure,the resulting residue was dissolved in CH2Cl2,and washed with water.The organic extract was evaporated.The residue was chromatographed on silica gel (xylene:acetic acid¼20:1as eluent)to give4d(0.77g,yield49%) as an orange powder and5d(0.56g,yield36%)as a yellow powder.Compound4d:M.p.222e224 C;1H NMR(400MHz,[D6] acetone,TMS):d¼1.04(t,J¼7.32Hz,6H),1.45e1.54(m,4H),1.70e1.78(m,4H),3.53(t,J¼7.32Hz,4H),7.02(dd,J¼8.80,2.44Hz,1H),7.12(d,J¼2.44Hz,1H),7.82e7.84(m,2H),8.17e8.22 (m,1H),8.29e8.38(m,3H),8.42e8.47(m,2H),8.51e8.55(m,2H), 8.80e8.82(m,1H),8.84e8.87(m,1H),9.11(d,J¼8.32Hz,1H),10.15 (d,J¼9.52Hz,1H);13C NMR(100MHz,[D3]chloroform,TMS): d¼14.07,20.42,29.38,51.34,94.20,109.28,113.51,118.04,120.04, 121.92,123.53,123.60,123.61,124.09,124.28,124.29,124.64,124.85, 125.00,125.65,125.66,125.81,125.84,125.95,126.15,127.15,127.18, 128.90,128.91,129.36,129.37,130.63,131.15,133.00,137.55,138.22, 147.67,158.93,161.68;IR(KBr):n¼1506,1635cmÀ1;elemental analysis calcd(%)for C41H34N2O2:C83.93,H5.84,N4.77;found:C 84.11,H5.84,N4.64.Compound5d:M.p.174e176 C;1H NMR(400MHz,[D6]acetone, TMS):d¼1.04(t,J¼7.56Hz,6H),1.48e1.53(m,4H),1.71e1.79 (m,4H),3.53(t,J¼7.56Hz,4H),7.01(dd,J¼8.76,2.44Hz,1H),7.18 (d,J¼1.92Hz,1H),7.78e7.87(m,2H),8.18e8.22(m,1H),8.31e8.39 (m,3H),8.43e8.49(m,2H),8.53e8.57(m,2H),8.64e8.67(m,1H), 8.84e8.86(m,1H),9.21(d,J¼8.28Hz,1H),10.18(d,J¼9.52Hz, 1H);13C NMR(100MHz,[D3]chloroform,TMS):d¼14.07,20.42, 29.38,51.39,94.67,109.05,113.60,116.13,117.37,119.97,121.44, 121.51,124.22,124.28,124.55,124.57,124.95,125.68,125.69,125.94, 126.01,126.13,126.18,127.13,127.35,127.82,129.06,129.47,129.52, 130.60,131.11,133.19,143.84,145.72,147.35,158.68,163.10;IR(KBr): n¼1507,1634cmÀ1;elemental analysis calcd(%)for C41H34N2O2:C 83.93,H5.84,N4.77;found:C84.08,H5.73,N4.70.Table1Spectroscopic data of4a e4f and5a,5c e5d in1,4-dioxane and in the solid state.Compound In1,4-dioxane In the solid statel max abs/nm(3max/dm3molÀ1cmÀ1)l maxfl/nm(F)l max ex/nm l max em/nm(F) 4a413(28900),360(17700)518(0.82)539578(0.11)4b420(31000),360(16000)535(0.81)555605(0.49)4c408(16000),371(27000)569(0.60)547602(0.07)4d436(32700),398(27100)536(0.83)528570(0.02)4e a410sh,392(38000)460(0.83)458490(0.43)4f388(36100)448(0.86)453486(0.63)5a367(30400)546(0.28)534573(0.11)5c410(4000),372(298000)571(0.12)510564(0.03)5d416(168000),396(34000),376(46200)550(0.43)508564(0.07)a Shoulder absorption.Table2Calculated absorption spectra for the compounds4a e4f and5a,5c e5d.m/D a Absorption(calc.)CI component c D m/D dl max/nm f b4a 5.35427 1.02HOMO/LUMO(79%)11.76HOMO/LUMO(79%)4b 5.09430 1.04HOMO/LUMOþ1(10%)12.363900.97HOMO/LUMOþ1(53%)4c 2.31HOMO/LUMO(30%) 4.943430.12HOMOÀ1/LUMO(42%)4d 2.04416 1.36HOMO/LUMO(62%)7.093410.10HOMO/LUMOþ1(35%)4e 4.094130.99HOMO/LUMO(87%)3570.09HOMO/LUMOþ3(41%)7.554f 2.31407 1.02HOMO/LUMO(89%)3140.64HOMO/LUMOþ1(38%) 6.583990.30HOMO/LUMO(62%)5a 3.443530.32HOMO/LUMOþ1(71%)13.00343 1.01HOMO-1/LUMO(28%)3660.14HOMO/LUMOþ2(56%)HOMO/LUMO(12%)5c 1.683520.89HOMO/LUMOþ1(74%) 3.813490.19HOMO-1/LUMO(50%)3810.47HOMO/LUMO(40%)5d 1.633540.26HOMO-1/LUMO(34%)7.37351 1.12HOMO/LUMOþ1(75%)a The values of the dipole moment in the ground state.b Oscillator strength.c The transition is shown by an arrow from one orbital to another,followed by its percentage CI(configuration interaction)component.d The difference in the dipole moment between the excited and the ground states.Table3Crystal data and structure refinement parameters for the compounds4c and5c. Compound4c5cMolecular formula C39H34N2O2C39H34N2O2 Formula weight562.71562.71Crystal size[nm]0.40Â0.10Â0.400.60Â0.40Â0.50 Reflns a(2q range,[ ])23(22.3e24.0)25(27.0e29.6) Crystal system Monoclinic MonoclinicSpace group P21/n P21/na[Ǻ]13.267(3)15.127(2)b[Ǻ]11.975(2)9.553(1)c[Ǻ]19.782(3)21.941(2)b[ ]107.13(1)108.461(7)V[Ǻ3]3003.6(8)3007.5(6)Z44r calcd[g cmÀ3] 1.244 1.243F(000)1192.01192.0m(Mo k a)[cmÀ1]0.760.76T[K]296.2296.2Scan mode u e2q u e2qScan rate[u minÀ1]8.0b8.0bScan width[ ] 1.52þ0.30 1.68þ0.302q max[ ]tan q tan qhkl range50.050.00/150/17À14/00/11Reflns measuredÀ23/22À26/24Unique reflns58195864Reflns observed with I0>2s I054925287R int13412954No.of parameters0.1350.018R453513Rw0.06670.050W0.11940.1130S(s2F2)À1(s2F2)À1Max.shift/error infinal cycle0.95 1.26Max.peak infinal diff.Map0.010.01[eǺÀ3]0.350.23Min.peak infinal diff.Map[eǺÀ3]À0.40À0.18a Number of reflections used for unit cell determination.b Up tofive scans.H.E.Ooyama et al./Dyes and Pigments91(2011)481e4884832-(2-hydroxylphenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth[1,2-d ]oxazole (4e):A solution of 3(1.00g,2.66mmol),salicylaldehyde (0.39g,3.22mmol),and ammonium acetate (4.11g,53mmol)in acetic acid (30mL)was stirred at 90 C for 5h.The reaction mixture poured into cold water,causing the precipitate and then filtered.The residue was dissolved in CH 2Cl 2,and washed with water.The organic extract was evaporated.The residue was chromatographed on silica gel (CH 2Cl 2as eluent)to give 4e (1.13g,yield 89%)as a yellow powder.Compound 4e:M.p.184.3 C;1H NMR (400MHz,[D 3]chloroform,TMS):d ¼1.01(t,6H),1.39e 1.49(m,4H),1.65e 1.72(m,4H),3.39(t,4H),6.86(dd,J ¼8.80,2.44Hz,1H),6.99(d,J ¼2.44Hz 1H),7.05e 7.09(m,1H),7.18(d,J ¼8.08Hz 1H),7.44e 7.48(m,1H),7.67e 7.75(m,2H),8.16e 8.19(m,2H),8.58e 8.63(m,2H),11.48(s,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼14.03,20.38,29.35,51.32,94.00,109.34,110.89,113.07,117.25,118.42,119.66,121.88,122.41,123.08,124.09,125.05,126.09,126.10,126.65,132.91,133.68,134.67,137.76,147.81,157.95,158.89,160.97;IR (KBr):n ¼3059cm À1;elemental analysis calcd (%)for C 31H 30N 2O 3:C 77.80,H 6.32,N 5.85;found:C 77.93,H 6.41,N 6.02.2-(4-tert-butylphenyl)-10-dibutylamino-benzofuro[2,3-e ]naphth[1,2-d ]oxazole (4f):A solution of 3(1.00g,2.66mmol),4-tert-butyl-benzaldehyde (0.52g, 3.20mmol),and ammoniumacetate (4.10g,53mmol)in acetic acid (20mL)was stirred at 90 C for 1h.The reaction mixture poured into cold water,causing the precipitate and then filtered.The residue was dissolved in CH 2Cl 2,and washed with water.The organic extract was evaporated.The residue was chromatographed on silica gel (CH 2Cl 2as eluent)to give 4f (1.00g,yield 74%)as a yellow powder.Compound 4f:M.p.220e 221 C;1H NMR (400MHz,[D 3]chlo-roform,TMS):d ¼1.01(t,6H),1.38(s,9H),1.39e 1.47(m,4H),1.64e 1.71(m,4H),3.40(t,4H),6.85(dd,J ¼8.80,2.44Hz,1H),6.98(d,J ¼2.44Hz,1H),7.58(d,J ¼8.80Hz,2H),7.65e 7.72(m,2H),8.17(d,J ¼8.80Hz,1H),8.31(d,J ¼8.56Hz,2H),8.58(d,J ¼7.60Hz,1H),8.72(d,J ¼7.60Hz,1H);13C NMR (100MHz,[D 3]chloroform,TMS):d ¼14.04,20.40,29.36,31.19,35.05,51.37,94.26,109.34,113.05,117.82,121.92,123.44,123.56,124.11,124.56,124.86,125.86,125.91,126.16,127.12,135.28,137.28,138.39,147.70,154.48,158.90,161.83;IR (KBr):n ¼1635cm À1;elemental analysis calcd (%)for C 35H 38N 2O 2:C 81.05,H 7.38,N 5.40;found:C 80.80,H 7.50,N 5.42.2.1.X-ray crystallographic studiesThe re flection data were collected at 23Æ1 C on a Rigaku AFC7S four-circle diffractometer by 2q e u scan technique,and using graphite-monochromated Mo K a (l ¼0.71069Å)radiation at 50kVONBu 2OOOO NON ORNBu 2Ri)543fe d c 4a = 84% 5a = 1%4b = 75% 5b = trace 4c = 31% 5c = 22%4d = 49% 5d = 36 %4e = 89% 5e = trace 4f = 74% 5f = traceCOOHCOOBuCO 2CH 2C 6F 5HOt -BuR =C7C6C5C4N1C2O3O12C11C10C9C8NBu 2C5C6Scheme 1.Synthesis of fluorophores 4and 5.i)CH 3COOH,CH 3COONH 4,90 C,1e 5h;ii)BuI,Na 2CO 3,DMF,100 C,10h;iii)penta fluorobenzyl bromide,Na 2CO 3,DMF,100 C,4h.00.20.40.60.81350400450500550600Wavelength/nm A b s o r b a n c eN o r m a l i z e d F l u o r e s c e n c e I n t e n s i t y (a .u .)4a 4b 4c4d 4e4f400450500550600650700Wavelength/nm4a 4b 4c 4d 4e 4fabFig.2.a)Absorption and b)fluorescence spectra of the compounds 4a e 4f in 1,4-dioxane.H.E.Ooyama et al./Dyes and Pigments 91(2011)481e 488484and 30mA.In all cases,the data were corrected for Lorentz and polarization effects.A correction for secondary extinction was applied.The re flection intensities were monitored by three stan-dard re flections for every 150re flections.An empirical absorption correction based on azimuthal scans of several re flections was applied.All calculations were performed using the teXsan [19]crystallographic software package of Molecular Structure DC-797585(4c )and CCDC-797586(5c )contain the supplementary crystallographic data (see Table 3)for this paper.These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via /data_request/cif .Compound 4c:Crystals of 4c were recrystallized from ethanol to afford air stable yellow prism.The transmission factors ranged from 0.96to 1.00.The crystal structure was solved by direct methods using SIR 92[20].The structures were expanded using Fourier techniques [21].The non-hydrogen atoms were re fined anisotrop-ically.Some hydrogen atoms were re fined isotropically,the rest were fixed geometrically and not re fined.Compound 5c:Crystals of 5c were recrystallized from ethanol to afford air stable yellow prism.The transmission factors ranged from 0.94to 1.00.The crystal structure was solved by direct methods using SIR 92[20].The structures were expanded using Fourier techniques [21].The non-hydrogen atoms were re finedanisotropically.Some hydrogen atoms were re fined isotropically,the rest were fixed geometrically and not re fined.3.Result and discussionThe synthetic pathway is shown in Scheme 1.Quinone 3[18]was allowed to react with various arylaldehydes in the presence of ammonium acetate to give the benzofuro[2,3-e ]naphthoxazole-type fluorophores 4and 5.The isomers 4were preferentially obtained in each case.In this reaction,NH 3resulting from ammo-nium acetate in the initial stage acts as the nucleophilic reagent to the 5-and/or 6-carbonyl carbon.In this case,NH 3preferentially attacks the 5-carbonyl carbon rather than the 6-carbonyl in spite of the similar steric reactivity of the two carbonyls.It was considered that the conjugated linkage of the dibutylamino group to the 6-carbonyl group would make the 6-carbonyl carbon less electrophilic than the 5-carbonyl carbon,so that the nucleophilic reagents (NH 3)preferentially attack the electrophilic 5-carbonyl carbon.As a result of these features this reaction afforded preferentially compounds 4.Moreover,the yields of the isomers 5were increased when the bulky aldehydes such as 9-anthraldehyde and 1-pyrenylcarbaldehyde were used as the reagent.It was considered that the reaction of the aldehyde with the resulting 5-imine group resulted in steric hindrance between the substituent of aldehyde and hydrogen atom0.20.40.60.811.2350370390410430450470490510530550Wavelength/nm5a 5c5d450500550600650700Wavelength/nm5a 5c 5dA b s o r b a n c eF l u o r e s c e n c e I n te n s i t y (a .u .)baFig.3.a)Absorption and b)fluorescence spectra of the compounds 5a ,5c and 5d in 1,4-dioxane.Fig.4.Calculated changes in electron density accompanying the first electronic excitation of 4a e 4f ,5a ,and 5c e 5d .The black and white lobes signify degreases and increase in electron density accompanying the electronic transition,respectively.Their areas indicate the magnitude of the electron density change.H.E.Ooyama et al./Dyes and Pigments 91(2011)481e 488485of adjacent benzen ring.These compounds were completely char-acterized by 1H,13C NMR,IR,and elemental analysis.A comparison of the observed and calculated UV e VIS spectra for compounds 4and 5have provided a powerful evidence for identi fication of their structures,which will be described later on.The absorption and fluorescence spectral data of 4a e 4f and 5a ,5c e 5d in solution are summarized in Table 1and their spectra in 1,4-dioxane are shown in Figs.1and 2,respectively.The visible absorption and fluorescence intensities of 4are much stronger than those of 5in 1,4-dioxane.The fluorophores 4a e 4d showed two absorption bands at around 408e 436and 360e 398nm and a single intense fluorescence band at around 518e 569nm in 1,4-dioxane.The fluorophores 4e and 4f exhibited an intense absorption band at around 388e 392nm and a single intense fluorescence band at around 448e 460nm in 1,4-dioxane.The fluorescence quantum yields (F )of the fluorophores 4were 0.82e 0.88expect for 4c .On the other hand,the fluorophores 5exhibit an intense absorption band at around 366e 396nm,and a relatively weak fluorescence band at around 550e 571nm (F ¼0.12e 0.43)in 1,4-dioxane (Fig.3).The F values of 4greater than those of 5suggest that the degree of donor e acceptor conjugation for the former is larger than that for the latter owing to the conjugated linkage of the dibutylamino group to the 6-substituents in 4.The photophysical spectra of 4and 5were analyzed by using semi-empirical molecular orbital (MO)calculations.The molecular structures were optimized by using MOPAC/AM1method [22],and then the INDO/S method [23,24]was used for spectroscopic calculations.The calculated absorption wavelengths and the transition character of the first absorption bands are collected in Table 2.The calculated absorption wavelengths and the oscillator strength values compare favourably with the observed spectra in 1,4-dioxane,although the calculated absorption spectra are blue-shifted.This deviation of the INDO/S calculations,giving high transition energies compared with the experimental values,has been generally observed [25,26].The calculations indicate that the longest excitation bands for both isomers 4and 5are mainly assignable to the transition from the HOMO to the LUMO,where HOMO is mostly localized on the 10-dibutylamino-benzofuro[2,3-e ]naphthoxazole moiety and the LUMO is mostly localized on the substituent moiety (R).The changes in the calculated electron density accompanying the first electron excitation are shown in Fig.4,which reveal a strong migration of intramolecular charge transfer from the 10-dibutylamino-benzofuro[2,3-e ]naphthoxazole moiety to the substituent moiety (R)in all the dyes except for 5c .In the longest excitation bands,the oscillator strengths (f )of isomers 4are rather larger than those of isomers 5,which is also in good agreement with the experimental data.The calculations reveal that a strong migration of intramolecular charge transfer from the donor moiety to the acceptor moiety for 4a e 4e with the conjugated linkage of the dibutylamino group to the substituents leads to intense visible absorption and fluorescence properties.In addition,in the dye 5c ,the calculated electron density changes accompa-nying the first electron excitation show mainly within the benzo-furonaphthoxazole moiety.This result is attributed to decrease of the donor e acceptor conjugation arising from steric hindrance between 10-dibutylamino-benzofuro[2,3-e ]naphthoxazole plane300350400450500550600Wavelength/nm 450500550600650700Wavelength/nm4a 4b 4c 4d 4e 4fN o r m a l i z e d F l u o r e s c e n c e I n t e n s i t y (a .u .)N o r m a l i z e d E x c i t a t i o n I n t e n s i t y (a .u .)abFig.5.a)Excitation and b)emission spectra of the compounds 4a e 4f in the solid state.350400450500550Wavelength/nm500520540560580600620640660680700Wavelength/nm5a 5c 5dN o r m a l i z e d F l u o r e s c e n c e I n t e n s i t y (a .u .)N o r m a l i z e d E x c i t a t i o n I n t e n s i t y (a .u .)abFig.6.a)Excitation and b)emission spectra of the compounds 5a ,5c e 5d in the solid state.H.E.Ooyama et al./Dyes and Pigments 91(2011)481e 488486。
