Optical property investigations of polystyrene capped Ca 2 P 2 O 7 :Dy 3+ persistent phosphor Abhilasha Jain a, *, Ashwini Kumar a , S.J Dhoble b , D.R Peshwe a a Department of Metallurgical and Materials Engineering, VNIT, Nagpur 440010, India b Department of Physics, R.T.M. Nagpur University, Nagpur 440033, India A R T I C L E I N F O Article history: Received 28 August 2014 Received in revised form 25 May 2015 Accepted 7 June 2015 Available online 27 June 2015 Keywords: Capping agent Photoluminescence Judd-ofelt radiative transitions Organic–inorganic ligand and phosphor A B S T R A C T By virtue of enhanced photosensivity, good optical response and better thermal stability, organic– inorganic hybrid materials are contemplated as one of the alternatives for designing advanced optoelectronic devices and innovative photonic applications. A novel inorganic organic hybrid Ca 2 P 2 O 7 : Dy 3+ phosphor has been fabricated by Pechini method. The optical property of synthesized phosphor is successfully altered by the in corporation of polystyrene sulfonic acid as capping agent in the colloidal solution. The phase purity and the average particle size of the prepared phosphor were calculated from X- ray diffraction (XRD) employing Debye Scherrer method. The morphological and chemical investigations were carried out through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. The radiative transitions are explained on the basis of Judd-Ofelt theory and on the basis of derived parameters, the radiative lifetime of persistent hybrid Ca 2 P 2 O 7 :Dy 3+ phosphor is calculated as 5.33 ms. This paper explores the mechanism leading to high photoluminescence efficiency using organic capping additives. The photoluminescence (PL) graphs reveal broad band emission at 482 nm (blue) and 573 nm (yellow) corresponding to 4 F 9/2 - 6 H 15/2 and 4 F 9/2 - 6 H 13/2 transitions of Dy 3+ , respectively. The Commission International De I-Eclairage (CIE) chromaticity co-ordinates were calculated from emission spectra and the values (x,y) were approaching to standard value of white emission. The synthesized pyrophosphate phosphors can thereby account in multiple potential applications including white light emitting diodes. ã 2015 Elsevier Ltd. All rights reserved. 1. Introduction Fabrication of luminescent inorganic lanthanide complexes with organic ligands have evoked an inquest and concern for the development of versatile applications as organic ligands can absorb abundant energy in near UV region and transfer the excitation energy to lanthanide ions through antenna effect [1]. The organic–inorganic hybrid phosphors have gained significance in the field of research as they provide an opportunity to design device with enhanced optical properties by blending the mutual features of both organic and inorganic components at molecular level. Afterglow is a promising property for varied optoelectronics applications because of long lasting emission characteristics. The polymer capped lanthanide phosphors find potential applications in elite aspects such as florescent probes [2], light emitting diodes [3], biological sensors [4]. Capping inorganic calcium pyrophosphate moieties with polymer molecules causes passiv- ation of surface defects which decreases the nonradiative recombination centers and increases photoluminescent intensity [5–7]. Besides, capping inhibits aggregation of particles and brings about stabilization of colloidal suspension which thereby enhances quantum confinement through particle isolation [8]. Among the lanthanide ions Dy 3+ with its 4f 9 electronic configuration exhibits two prominent emission bands in the visible region, blue at approximately 573 nm due to 4 F 9/2 – 6 H 13/2 characteristic transition and yellow–orange at approximately 482 nm due to 4 F 9/2 – 6 H 15/2 characteristic transition. It is feasible to achieve near white light emission by regulating yellow to blue intensity ratio [9]. There upon, Dy 3+ activated luminescent phosphors are captivating soaring consideration in view of their potential applications such as white light emitting diode phosphors [10]. To outstrip the low absorption coefficient of Dy 3+ it is essential to have high emission intensity. This problem can be resolved by forming a complex with an organic chromophore (ligands) [11] that absorbs efficiently in the UV–vis range and transfers its energy onto lanthanide ions. One of the main causes of non- radiative * Corresponding author. E-mail address: abhilasha.vnit@gmail.com (A. Jain). http://dx.doi.org/10.1016/j.materresbull.2015.06.018 0025-5408/ ã 2015 Elsevier Ltd. All rights reserved. Materials Research Bulletin 70 (2015) 980–987 Contents lists available at ScienceDirect Materials Research Bulletin journa l homepage: www.elsevier.com/locate/matresbu