Contents lists available at ScienceDirect Materials Science in Semiconductor Processing journal homepage: www.elsevier.com/locate/mssp Photocatalytic, antibacterial, optical and magnetic properties of Fe-doped ZnO nano-particles prepared by sol-gel Zohra Nazir Kayani a, ⁎ , Eram Abbas a , Zeb Saddiqe a , Saira Riaz b , Shahzad Naseem b a Lahore College for Women University, Lahore 54000, Pakistan b Centre of Excellence in Solid State Physics, University of the Punjab, Lahore 54950, Pakistan ARTICLE INFO Keywords: Nanoparticles Photo-catalytic Antibacterial activity Optical property Magnetic properties ABSTRACT Fe doped ZnO nanoparticles with varying Fe concentrations 1–17% were fabricated by sol-gel route. Fourier- transform infrared spectrometer (FTIR) study established Fe doping and incorporation of Fe in ZnO lattice. X-ray diffraction (XRD) results indicated that the synthesized nano-particles were poly-crystalline with the hexagonal wurtzite structure. No impurity or iron compound peak was foud. The band gap of the synthesized nano-particles was observed to increase with the increase of Fe percentage and hence displayed a blue shift but the band gap of Fe doped ZnO is lesser than the band gap of undoped ZnO. Magnetic study assured a ferromagnetic trend for all the synthesized nano-particles due to Fe doping in ZnO. The effects of Fe percentage on the antibacterial effi- ciency against two different bacteria Escherichia coli (E.coli) and Pseudomonas aeruginosa (P. aeruginosa) were probed. The antibacterial efficiency was best for 14 and 17 at% of the Fe doping level. Photocatalytic activity was determined by degradation of methylene blue (MB) dye in ethanol solution under sunlight. ZnO with 1% Fe showed the better photo- catalytic property. 1. Introduction Variety of nanoparticles is synthesized by researchers keeping in view their applications in diverse fields [1,2]. ZnO [3–5] is a wide band gap semiconductor material which is abundant, cheap and nontoxic. ZnO has numerous applications owing to its microwave absorbing ability and the infrared transmission ability [6]. To enhance the prop- erties of ZnO, doping with the metal ion is the most effective route which produces structural changes. Doping of the ZnO with a very minute amount of transition metal produces ferromagnetism. Both charges and spins of the electron are used for optoelectronic and opto- magnetic gadgets, for example light emitting appliances, quantum computers and spin field-effect transistors [7]. The optical band gap energy and ferromagnetic properties can be controlled by doping the semiconductor with transition metals such as Fe [7], Co [8], Mn [9], Ni [10,11] and Cu [12]. Fe doped ZnO nanoparticle generally shows fer- romagnetic behavior [5,13–15] at room temperature while some re- searchers reported antiferromagnetic nature [14–16]. The difference in the magnetic trend of Fe doped ZnO shows that ferromagnetism relays on the route and specification used in the fabrication. Curiosity to confirm the magnetic nature of Fe doped ZnO motivated to carry out this project. Fe doped ZnO nanoparticles play a crucial role in the photo-degradation of organic pollutants so they have become essentials for the photo-catalysis [17]. Hui et al. [18] discovered that Fe doped ZnO nanoparticles showed good photo-catalytic activity than un-doped ZnO nanoparticles [19]. Several researchers [20–22] have prepared Fe doped ZnO nanoparticles but the blend of doping method and optical properties control to increase the photo-catalytic activity is infrequent [18]. ZnO is antibacterial agents which useful for environment, food packaging, synthetic textiles and biomedicine. Doping of ZnO plays an important in the enhancement of antibacterial properties. This provides motivation to study antibacterial properties of Fe doped ZnO nano- particles. Many routes are available for the fabrication of Fe doped ZnO na- noparticles such as co-precipitation method [7], solid state reaction [23], sol-gel [17,24], hydrothermal synthesis [25], solution combustion method [26] and the combination of precipitation method and calci- nation process [18]. Amid all these synthesis techniques, the sol-gel method is selected owing to its easiness, low temperature synthesis, versatility, excessive control over composition and potential to syn- thesize nano-particles at large scale with reasonable expenditure. In this scheme Fe-doped ZnO nanoparticles were synthesized by sol- gel route which includes an unreported doping concentration of Fe (1, 4, 7, 14, 17%) for the fabrication of Fe doped ZnO nano-particles which were investigated by using X-ray diffraction (XRD), UV–VIS–NIR Spectrophotometer, Fourier-transformed infrared spectrometer (FTIR), https://doi.org/10.1016/j.mssp.2018.08.003 Received 4 May 2018; Received in revised form 17 July 2018; Accepted 5 August 2018 ⁎ Corresponding author. E-mail address: zohrakayani@yahoo.com (Z.N. Kayani). Materials Science in Semiconductor Processing 88 (2018) 109–119 1369-8001/ © 2018 Elsevier Ltd. All rights reserved. T