An orange-red [Ru(bpy)3]2+-DNA-Cu2+ composite film (bpy =2,2'-bipyridine) was fabricated on an indium-tin (ITO) surface based on electrostatic interactions among [Ru(bpy)3]2+,DNA and Cu2+ by using self-standing cast methods.The photoinduced electron transfer (PET) properties of the resultant composite film mediated by DNA were studied by means of steady-state and time-resolved fluorescence spectroscopy,UV-visible absorption spectroscopy,fluorescence microscopic imaging and scan electron microscopy.The [Ru(bpy)3]2+-DNA-CC+ composite film with molar ratio of 10:20:1 shows an obvious absorption band (450 nm) and an intense emission peak (λem =595 nm),whose emission exhibits a single-exponential decay with τ=188.6 ns and is quenched by Cu2+ via DNA-mediated PET mechanism,indicating that the quenching constant is 6.94 × 103 L · mol-1 and quenching rate constant is 3.80× 1010 L · mo1-1 · s-1.The increasing molar ratio of Cu2+ in composite films (10-fold) leads to an 11 nm blue-shift of the emission peak,which is dramatically weakened by Cu2+ via a static quenching mechanism In addition,compared with the emission quenching of DNA-[Ru (bpy) 2 (tatp)] 2 + (tatp =1,4,8,9-tetra-aza-triphenylene)tuned by Cu2+,which is present either in solutions or in composite films,Cu2+ only quenches the emission of [Ru(bpy)3]2+bound to DNA via an electrostatic interaction mode in composite films.%由于DNA与[Ru(bpy)3]2+(bpy=2,2'-联吡啶)及Cu2+间的静电作用,用自铸膜法在铟锡氧化物(ITO)上制备了橙红色Ru(bpy)3]2+-DNA-Cu2+复合膜,并应用稳态和暂态荧光光谱、紫外可见光谱、荧光显微镜和扫描电镜对复合膜进行了表征和DNA介导的光诱导电子转移(PET)研究.结果表明,[Ru(bpy)3]2+-DNA-Cu2+复合膜(摩尔比为10:20:1)呈现了明显的吸收特征峰(450 nm)和发射峰(λcm=595 nm),发光呈单指数衰减,发光寿命为188.6 ns,Cu2+通过DNA介导PET机制猝灭[Ru(bpy)3]2+发光,猝灭常数为6.94×103 L·tnol-1,猝灭速率常数为3.80×1010 L·mol-1·s-1；复合膜中Cu2+摩尔比(10倍)的增大使发射峰蓝移了11 nm,吸收和发射强度衰减至消失,Cu2+通过静态猝灭机制削弱[Ru(bpy)3]2+发光.此外,对比于溶液和复合膜中Cu2+对[Ru(bpy)2 (tatp)]2+-DNA(tatp=1,4,8,9-四氮三苯)的发光调控,Cu2+仅能因静电作用猝灭复合膜中[Ru(bpy)3]2+的发光.
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