Multi-walled carbon nanotubes supported Cu-doped ZnO nanoparticles and their optical property

Multi-walled carbon nanotubes (MWNTs)/Cu-doped ZnO composite powders were prepared by co-precipitation method, and were characterized by X-ray diffraction, electron microscopy, fluorescence spectrum, and ultraviolet spectrum. Experimental results show that the MWNTs can be modified by Cu-doped ZnO nanoparticles with hexagonal wurtzite structure after annealed at 450?°C, and the nanoparticle size is about 15?nm. Two ultraviolet (UV) peaks and a green band centered at about 510?nm are observed in the fluorescence spectrum of MWNTs/Cu-doped ZnO composite powder annealed at 450?°C. Furthermore, MWNTs and Cu doping significantly improve the UV absorption ability of ZnO.     

三维荧光与紫外光谱联合表征样品中猝灭剂赋存状态:以胡敏酸与Fe(Ⅲ)相互作用为例

利用三维荧光-紫外光谱表征了荧光猝灭剂的赋存状态,当样品体系中存在Fe(Ⅲ)的情况下,胡敏酸会发生荧光猝灭现象,而其紫外光谱基本不受影响。考察了胡敏酸荧光强度I值(Ex/Em=300 nm/510nm)和紫外吸光度A值(UV300)的变化,I/A比值越小,说明水样中猝灭剂Fe(Ⅲ)浓度越高。当胡敏酸为10,15和20 mg·L~(-1)时,根据Stern-Volmer公式I/I_0=1-f_c×K_c×[c]/(1+K_c×[c])以及拟合函数I/A=f×[k/(CFe~(3+)+c)+b],拟合得到荧光猝灭常数K_c=1.08~1.15,比例系数f_c=1.10~1.14之间,胡敏酸荧光强度值与吸光度比值(I/A)及铁离子浓度(C_(Fe~(3+))相关曲线系数f=0.83~1.19,k=587.19~612.19,c=0.87~0.92,b=-87.09~-46.36,拟合曲线相关性R~2均为0.99。Stern-Volmer公式描述了Fe(Ⅲ)对胡敏酸荧光的猝灭作用,但实际样品测定时难以获得无猝灭剂时的荧光强度I_0。基于荧光强度I_0与紫外吸光度A之间的内在联系,两者比值I/A与Fe(Ⅲ)浓度c的拟合函数亦可以反映Fe(Ⅲ)对胡敏酸荧光的影响。利用拟合公式预测城市污水厂及纳污河流样品的树脂分离富集液中铁离子浓度,与电感耦合等离子体发射光谱仪实际测量值相比,铁离子浓度较高的情况下(铁离子浓度大于0.4 mg·L~(-1)时)预测结果较好,可以判断猝灭剂的存在及相应浓度。     

聚氨酯/聚丙烯酸酯复合乳液的紫外光谱研究

以水性聚氨酯(PU)分散液为种子,采用无皂乳液聚合技术合成出了聚氨酯／聚丙烯酸酯(PUA)复合乳液。紫外光谱研究发现,PU乳液的,n-π迁紫外吸收峰的λmax随溶液浓度增加明显红移。对于PU分散液,随着亲水性扩链剂用量增加,紫外光谱吸光度值变小;随着NCO/OH摩尔比增大,吸光度增大。对于PUA复合乳液,亲水性扩链剂用量取7．5％时,吸光度值最小;而第二阶段聚合引发剂种类对紫外光谱影响不大。紫外光谱的吸光度值反映了乳液粒子平均粒径的大小;随着NCO／OH摩尔比增大,吸光度增大。对于PUA复合浮液,亲水性扩链剂用量取7．5％时,吸光度值最小;而第二阶段聚合引发剂种类对紫外光谱影响不大。紫外光谱的吸光度值反映了乳液粒子平均粒径的大小。     

利用紫外和荧光光谱指示臭氧降解典型内分泌干扰物的研究

污水处理和再生回用是缓解我国水污染严重和水资源紧张的有效途径。二级出水水量大、稳定且水质相对良好，是污水再生回用的良好水源。然而，二级出水中广泛存在内分泌干扰物(endocrine disrupting compounds, EDCs)，对其再生回用形成了潜在的安全风险。臭氧氧化是去除EDCs的有效方法，但二级出水中存在着多种有机质，臭氧降解EDCs的过程中同时和有机质中的活性基团发生反应，引起一定程度的臭氧衰减，从而对EDCs的臭氧氧化造成影响。有机质中与臭氧反应的活性基团变化可反映为特征紫外和荧光光谱的变化。因此，可以采用特征紫外和荧光光谱变化来指示臭氧对EDCs的降解效果。本研究通过考察二级出水中主要的三类有机质代表(腐殖酸、牛血清蛋白和海藻酸钠)对臭氧衰减动力学的影响，进一步解析有机质对5种典型EDCs臭氧降解规律的影响，在此基础上考察特征紫外和荧光光谱与EDCs臭氧降解效果的关系，以期筛选出二级出水中EDCs臭氧降解效果的指示参数，并建立其与EDCs降解效率之间的定量关系，从而以这些指示参数来预测EDCs的臭氧化降解情况，简化EDCs检测。该研究中五种目标EDCs(雌酮(E1)、雌二醇(E2)、雌三醇(E3)、17α-乙炔基雌二醇(EE2)和双酚A(BPA))采用超高效液相色谱-双质谱联用技术同时分析定量。通过考察不同种类二级出水有机质对臭氧衰减动力学和EDCs降解效果的影响发现三种有机质均可促进臭氧衰减，对EDCs的臭氧化降解效率均有抑制作用，顺序依次是腐殖酸>牛血清蛋白>海藻酸钠；三种有机质的紫外-可见光谱特征谱图表明有机质中能与臭氧反应的活性基团在紫外-可见光有特定的响应特征；三种有机质的三维荧光光谱特征谱图表明富里酸类腐殖质及喹啉类结构对臭氧消耗均有显著的贡献；腐殖酸在254，258和280 nm的紫外吸光度及激发波长/发射波长(Ex/Em)=240/396 nm，Ex/Em=345/436 nm的荧光吸光度去除率与臭氧投加量显著相关；其中280 nm处的特征紫外吸光度UVA₂₈₀，特征荧光吸光度Ex/Em=240/396 nm可作为臭氧降解EDCs的指示参数，具体为UVA₂₈₀去除率大于18%或者Ex/Em=240/396 nm去除率大于35%时，1 μmol·L-1的5种EDCs几乎被完全降解。此研究对污水处理厂臭氧去除EDCs过程中臭氧剂量的优化及EDCs去除效果具有指导作用，且可避免复杂的EDCs检测。     

昆明松华坝库区表层土壤溶解性有机质(DOM)的光谱特性

单一的光谱技术不能对溶解性有机质(dissolved organic matters,DOM)的结构特征和来源进行全面的分析,因此,本研究选择紫外-可见光谱和三维荧光光谱技术相结合的方法,对昆明松华坝库区表层土壤中DOM的组成结构和来源进行了研究。结果表明,所有样品的紫外-可见光谱曲线均呈现出相似的特征,吸光度随着波长的增加而降低,并在250～280 nm波段存在一个明显的肩状吸收峰。A₂₅₀/A₃₆₅(波长在250和365 nm处紫外吸光度的比值)的范围在2.59～5.21之间,说明DOM中主要物质为富里酸或者胡敏酸且分子量较高;SUVA₂₅₄(单位DOC浓度在波长254 nm处的吸收系数)和SUVA₂₆₀(单位DOC浓度在波长260 nm处的吸收系数)分别为1.19～3.00和1.15～2.89,两者之间存在十分显著的相关性,表明该地区土壤DOM的腐殖化程度相对较高并含有较多的疏水组分。三维荧光光谱显示,所有DOM样品中主要存在3个特征峰：紫外光区类富里酸峰、可见光区类富里酸峰和类腐殖酸峰,而类蛋白峰不显著。荧光指数(fluorescence index, FI)总体上接近于1.4,表明该地区土壤DOM以外源输入为主;自生源指标(autochthonous index, BIX)均小于1,自生源特征不明显并且生物利用性较低,这可能与当地较强的人类活动有关。以上研究结果可以为进一步探讨DOM对有机或重金属污染物迁移转化的影响提供理论依据。     

不同临界保留因子下天然有机物亲疏水组分光谱特性

吸附树脂层析法是表征环境水样有机物亲疏水组分分布的常用方法。作为柱层析的基本参数,临界保留因子对亲疏水物质的吸附及分离效果具有潜在影响。以河北某水库的水样为例,将有机物分为亲水物(HIS)、疏水酸(HOB)、疏水碱(HOA)和疏水中性物(HON),考察了在不同临界保留因子分离条件下(k′_cr=5, 10, 25, 50, 100)亲疏水组分有机物含量分布,并着重考察了其光谱学特性。研究发现,亲疏水组分的浓度分布取决于k′_cr值的设置,疏水组分的比例和疏水程度随k′_cr的增大而增大。在250~280 nm波长范围内,亲水组分HIS的紫外吸光度随k′_cr的增高而增高,而疏水组分HOA和HOB则呈现相反趋势,亲水与疏水组分之间的紫外光谱差异性随k′_cr增大而增大。此外,疏水组分单位质量浓度的吸光度对k′_cr的取值敏感,推测k′_cr可能影响所得组分的芳香族官能团性质。进一步考察了各组分的三维荧光光谱,并采用荧光区域积分和荧光指数对图谱进行解析。结果表明,亲疏水组分的荧光峰形态、荧光区域分布和荧光团密度与k′_cr值有关,荧光指数BIX,HIX_em和Peak T/C对k′_cr的取值敏感,说明k′_cr可能对所得组分的具体化学组成乃至迁移转化行为产生影响。因此在分离并表征环境水样的亲疏水组分分布时,应特别注意临界保留因子的设置并明确标明其取值。     

pH值对秸秆腐殖化溶解性有机质紫外光谱和荧光光谱的影响

秸秆是农业生产的主要副产物,也是农业面源污染的新源头。秸秆还田能有效解决其减量化和资源化利用问题,国家“十二五”规划已明确提出“加大秸秆还田力度,保障农业的稳产、增产和可持续发展”。现阶段,对于典型地区不同环境条件下还田秸秆腐殖化行为的研究不多,同时对于腐殖化组分的精细化检测和分析也有待加强。针对黄土区秸秆还田问题,以紫外光谱法和荧光光谱法为切入点,分析pH值对腐殖化产物溶解性有机质(Dissolved organic matter, DOM) 性质的影响,深度揭示秸秆腐殖化过程的内在本质。结果表明：在200～700 nm波长范围内,DOM的紫外吸收强度先增加后减小,主要吸收峰出现于240 nm附近。相对于中性(pH 7)体系,酸性(pH 6)和碱性 (pH 8和9) 条件下的最大吸收波长λ_max值红移。SUVA₂₅₄,E₃/E₄和A₂₅₃/A₂₀₃比值的规律性变化说明反应体系腐殖化程度较低,这与秸秆腐殖化周期较短有关。黄土浸提液DOM的荧光峰主要位于λ_ex/em=250/330和λ_ex/em=325/450区域,分别归属为紫外区类富里酸荧光峰和可见光区类富里酸和腐殖酸类物质荧光峰。随着腐殖化体系pH值的升高,荧光峰位发生红移,表明DOM苯环结构逐渐增多,共轭度有所增加,同时在λ_ex/em=250/450附近检测到新荧光峰。pH值对荧光强度的影响主要体现在紫外区类富里酸荧光峰,峰强先升高后下降,而对可见光区荧光峰强影响不大,这与浸提液的缓冲效应、荧光猝灭(或副反应)和DOM组分结构有关。紫外光谱和荧光光谱能够一定程度上阐释pH值对秸秆腐殖化DOM性质的影响。     

CdS/ZnO纳米复合结构制备及荧光特性研究

为增强CdS纳米粒子的荧光强度,以及稳定性,研究了Cd,S不同质量比,有无稳定剂等条件下CdS纳米粒子的制备及荧光特性。在碱性条件下,利用水热法合成了CdS/ZnO的纳米复合结构,并对所有样品进行了XRD、荧光光谱和SEM表征。测试结果表明所制备的CdS纳米粒子和CdS/ZnO的纳米复合结构粒子成分单一且纯净;ZnO复合在CdS表面;在紫外光(328.5 nm)激发下,CdS/ZnO纳米复合结构的发射峰位于463 nm处,峰形窄而对称,CdS/ZnO纳米复合结构的荧光强度比CdS纳米粒子的荧光强度有显著增强,且CdS和ZnO物质量之比为1∶1条件下,荧光强度最高,其荧光效率比单一CdS纳米粒子高出11%。通过第一性原理计算结果表明,CdS能带结构中,Cd-4d,S-3p和Cd-5s能带分别由5条、3条和1条能级构成,对比不同轨道的分态密度强度,看出CdS的导带边主要由Cd-5s轨道贡献,而价带边主要由S-3p轨道贡献,能量在-7 eV附近的电子态主要由Cd-4d轨道贡献。而ZnO上价带主要由O-2p电子构成,靠近费米能级的价带区域则主要由Zn-3d电子贡献,在导带部分,主要来源于Zn-4s和O-2p电子。由于在两种材料的复合结构中Zn-3d电子的能级和S-3p电子的能级接近,存在着二型带阶结构使能带变窄,容易形成跃迁,减小电子-空穴的复合,从而促进复合结构荧光效率的提高。     

Synthesis and characterization of hybrid Ag-ZnO nanocomposite for the application of sensor selectivity

Facile, rapid, and environmentally benign hybrid Ag-ZnO nanocomposites were synthesized by two steps from green synthesis approach at room temperature. The absence of an impurity peak in X-ray diffraction (XRD) pattern confirmed the formation of polycrystalline nanocomposite material. An additional peak (111) of Ag was detected along with ZnO crystalline wurtzite structure. The surface area electron diffraction (SAED) pattern further confirmed the crystallinity of nanocomposites. The compositional analysis of hybrid Ag-ZnO was determined by EDS-mapping and confirmed the presence of Zn, O and Ag in the composite. The room-temperature photoluminescence (PL) spectra of hybrid Ag-ZnO depict a weak ultraviolet (UV) emission at 385 nm, and the strong visible emission at ∼600 nm, while increasing the Ag concentration in to ZnO matrix, the UV peak was completely disappeared and major visible peak was moved to ∼500 nm indicated to the best optimal detection peak for sensors. The fluorescence spectra were measured with respect to Ag concentrations of Ag-ZnO nanocomposite at room temperature to investigate the functionality and the selectivity of nanomaterials. This work opens a notable way to fabricate Ag-ZnO nanohybrids, and makes a significant contribution to the fluorescence based sensor applications.     

Photocatalytic,sonocatalytic and sonophotocatalytic degradation of Rhodamine B using ZnO/CNTs composites photocatalysts

A series of ZnO nanoparticles decorated on multi-walled carbon nanotubes (ZnO/CNTs composites) was synthesized using a facile sol method. The intrinsic characteristics of as-prepared nanocomposites were studied using a variety of techniques including powder X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), transmission electron microscope (TEM), scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX), Brunauer Emmett Teller (BET) surface area analyzer and X-ray photoelectron spectroscopy (XPS). Optical properties studied using UV–Vis diffuse reflectance spectroscopy confirmed that the absorbance of ZnO increased in the visible-light region with the incorporation of CNTs. In this study, degradation of Rhodamine B (RhB) as a dye pollutant was investigated in the presence of pristine ZnO nanoparticles and ZnO/CNTs composites using photocatalysis and sonocatalysis systems separately and simultaneously. The adsorption was found to be an essential factor in the degradation of the dye. The linear transform of the Langmuir isotherm curve was further used to determine the characteristic parameters for ZnO and ZCC-5 samples which were: maximum absorbable dye quantity and adsorption equilibrium constant. The natural sunlight and low power ultrasound were used as an irradiation source. The experimental kinetic data followed the pseudo-first order model in photocatalytic, sonocatalytic and sonophotocatalytic processes but the rate constant of sonophotocatalysis is higher than the sum of it at photocatalysis and sonocatalysis process. The sonophotocatalysis was always faster than the respective individual processes due to the more formation of reactive radicals as well as the increase of the active surface area of ZnO/CNTs photocatalyst. Chemical oxygen demand (COD) of textile wastewater was measured at regular intervals to evaluate the mineralization of wastewater.     

Carbon quantum dots supported ZnO sphere based photocatalyst for dye degradation application

A Carbon quantum dots supported ZnO hollow Sphere (ZnO/C-dots) were synthesized through a solvothermal method using polyethylene glycol 400 (PEG 400) as a solvent. The phase and crystal structure of as-prepared ZnO/C-dots photocatalyst were characterized by powder X-ray diffraction (XRD). The surface morphology and size of the composite were analyzed using field emission scanning microscopy (FE-SEM). The optical properties of the as-prepared nanocomposites were examined using UV–visible (UV–Vis) spectrometer. The photocatalytic activity of pure ZnO and ZnO/C-dots nanocomposites were evaluated by the degradation of methylene blue (MB) under UV–Visible light irradiation. The ZnO/C-dots nanocomposites exhibited maximum photocatalytic MB dye degradation efficiency of 96% which is much higher that the pure ZnO (63%). The enhanced photocatalytic activity of ZnO/C-dots is due to the extended light absorption in the visible region and suppressed photoexcited electron-hole pair recombination rate. Moreover, the activity of photocatalyst after five cycles exhibits high stability, which is vital for the sustainable photocatalytic procedures. It is concluded that the prepared ZnO/C-dots composite have low cost, good stability and has a great potential application for Photocatalytic dye degradation.     

Stable aqueous ZnO nanoparticles with green photoluminescence and biocompatibility

Semiconductor quantum dots (QDs) as a kind of biological labeling material have many unique fluorescence properties relative to conventional organic dyes, which can be used for long-term fluorescence tracking. In this work, a facile method was developed for synthesizing water-stable ZnO nanoparticles with green emission. The as-synthesized ZnO nanoparticles were shown to be highly stable and soluble in water. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) as well as UV–vis and fluorescence spectrophotometry (PL) were employed to investigate the structures and properties of ZnO nanoparticles. Furthermore, hemolysis assay was performed to evaluate the biocompatibility of these ZnO nanoparticles in vitro. The results indicate that the as-prepared ZnO nanoparticles have biocompatibility, which make them a promising cell label.     

Photoluminescence from ZnO-SiO2 opals with different sphere diameters and thicknesses

We systematically investigated the photoluminescence (PL) and transmittance characteristics of ZnO-SiO₂ opals with varied positions of the stop-band and film thicknesses. An improved ultraviolet (UV) luminescence was observed from ZnO-SiO₂ composites over pure ZnO nanocrystals under 325 nm He-Cd laser excitation at room temperature. The UV PL of ZnO nanocrystals in SiO₂ opals with stop-bands center of 410 nm is sensitive to the thickness of opal films, and the UV PL intensity increases with the film thickness increasing. The PL spectra of ZnO nanocrystals in SiO₂ opals with stop-bands center of 570 nm show a suppression of the weak visible band. The experimental results are discussed based on the scattering and/or absorbance in opal crystals.     

聚邻甲基丙烯酰胺基苯甲酸/纳米ZnO复合物的制备及其荧光性能研究

利用原子转移自由基聚合(ATRP)法对合成的新单体邻甲基丙烯酰胺基苯甲酸(o-MAABA)进行聚合,通过核磁验证得到符合预先设计的、结构明确的聚合物,聚合物分子量为7900;将纳米ZnO引入到该聚合物P(o-MAABA)中,得到聚合物/纳米ZnO粒子复合物.用红外光谱和差热分析方法对聚合物和复合物进行了表征,并采用透射电镜(TEM)观察了复合物粒子的形貌.红外光谱表明纳米ZnO确实被引入到聚合物链中,并且与聚合物中的某些官能团发生了一定的相互作用;差热分析表明P(o-MAABA)/纳米ZnO复合物的热稳定性较原来聚合物P(o-MAABA)有所提高;TEM观察表明复合物粒子基本为球状,表面较为光滑.P(o-MAABA)/纳米ZnO复合物表现出特殊的荧光性能,与聚合物相比荧光光谱发生红移,并且复合物溶解性较好,能成膜,可望在发光材料方面得到应用.     

Novel ultraviolet photoluminescence of ZnO/ZnGa2O4 composite layers

ZnO/ZnGa₂O₄ composite layers were synthesized by simple thermal oxidation of ZnS substrates with gallium in the air. The continuous-wave and time-resolved photoluminescence measurements for the composites were performed at room temperature. It is found that the visible deep level emission from ZnO in ZnO/ZnGa₂O₄ composite layer was almost suppressed. In addition, the UV emission with long lifetime was also observed in comparison with that of pure ZnO layer without ZnGa₂O₄.     

Fabrication of surface‐enhanced Raman scattering‐active ZnO/Ag composite microspheres

We show in this paper how zinc oxide (ZnO)/silver (Ag) composite microspheres can be prepared by the reduction of Ag(NH₃)₂⁺ with the reducing agent formaldehyde in aqueous solution on the surface of ZnO microspheres. During the preparation, Sn²⁺ was absorbed on the surface of ZnO microspheres for sensitization and activation, and then Ag(NH₃)₂⁺ was reduced to Ag nanoparticles by the reducing agent to obtain ZnO/Ag composite microspheres. SEM and TEM images revealed silver nanoparticles with a diameter ranging from tens to 100 nm. X‐Ray photoelectron spectra (XPS), X‐ray diffraction (XRD) patterns and UV‐vis spectra were used to characterize the structure of the ZnO/Ag composite microspheres. The origin of the surface‐enhanced Raman scattering properties was traced to the surface of the ZnO/Ag composite microspheres. The enhancement factor was estimated in detail, and the enhancement mechanism for the SERS effect was also investigated. Copyright © 2007 John Wiley & Sons, Ltd.     

Improved photocatalytic performance of Pd-doped ZnO

ZnO and Pd-doped ZnO photocatalysts with different molar ratio of Pd/Zn (1/100, 2/100, 3/100 and 4/100) were prepared by a sol-gel method. The photocatalysts prepared were characterized by BET surface area, X-ray diffraction (XRD), UV/vis diffuse reflectance (DRS) and surface photovoltage spectroscopy (SPS), respectively. The results show that doping Pd into ZnO decreases the BET surface area. The XRD spectra of the Pd-doped ZnO catalysts calcined at 773 K show only the characteristic peaks of wurtzite-type. Doping Pd into ZnO increases the absorbance of ZnO in visible region and enhances the photoinduced charge separation rate. The photocatalytic activity of Pd-doped ZnO photocatalysts for decolorization of methyl orange (MO) solution was evaluated, of all the photocatalysts prepared, the Pd-doped ZnO with 3/100 possesses the best photocatalytic activity. The results of further experiments show that increased adsorption ability of light and high separation rate of photoinduced charge carriers all play an important role in promotion of photocatalytic activity of Pd-doped ZnO nanostructure.     

背入射Au/ZnO/Al结构肖特基紫外探测器

设计制作了一种Au/ZnO/Al结构的紫外探测器,光的入射方式采用背入射式。ZnO薄膜是用磁控溅射在蓝宝石衬底上制备的。I-V测试表明:Au与ZnO形成了肖特基接触。得到探测器的光响应峰值在352nm,截止边为382nm,可见抑制比达一个量级。由于该探测器是一种垂直结构器件,对于进一步实现ZnO紫外探测器阵列及单光子探测有很好的研究价值。     

Sonocatalytic degradation of some dyestuffs and comparison of catalytic activities of nano-sized TiO2, nano-sized ZnO and composite TiO2/ZnO powders under ultrasonic irradiation

Here, a novel sonocatalyst, composite TiO2/ZnO powder, was prepared through the combination of nano-sized TiO2 and ZnO powders. Because of the appropriate adsorbability to organic pollutants and special crystal interphase between TiO2 and ZnO particles, the composite TiO2/ZnO powder exhibits a high sonocatalytic activity under ultrasonic irradiation during the degradation of acid red B. Especially, the sonocatalytic activity of composite TiO2/ZnO powder with 4:1 molar proportion treated at 500 degrees C for 50 min showed obvious improvement compared with pure nano-sized TiO2 and ZnO powders. When the experimental conditions such as 10mg/L acid red B concentration, 1.0 g/L catalyst addition amount, pH=7.0, 20 degrees C system temperature, 100 min ultrasonic time and 50 mL total volume were adopted, the satisfactory degradation ratio and rate were obtained. All experiments indicate that the sonocatalytic method using composite TiO2/ZnO powder may be a more advisable choice for the treatments of non- or low-transparent organic wastewaters in future.     

Effect of doping and annealing on the physical properties of ZnO:Mg nanoparticles

Well-dispersed undoped and Mg-doped ZnO nanoparticles with different doping concentrations at various annealing temperatures are synthesized using basic chemical solution method without any capping agent. To understand the effect of Mg doping and heat treatment on the structure and optical response of the prepared nanoparticles, the samples are characterized using X-ray diffraction (XRD), energy-dispersive X-ray (EDX), UV–Vis optical absorption, photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The UV–Vis absorbance and PL emission show a blue shift with increasing Mg doping concentration with respect to bulk value. UV–Vis spectroscopy is also used to calculate the band-gap energy of nanoparticles. X-ray diffraction results clearly show that the Mg-doped nanoparticles have hexagonal phase similar to ZnO nanoparticles. TEM image as well as XRD study confirm the estimated average size of the samples to be between 6 and 12 nm. Furthermore, it is seen that there was an increase in the grain size of the particles when the annealing temperature is increased.