Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-019-01103-8 Energy transfer-enhanced external power conversion efciency in blended polymeric thin flm solar devices Nazir Mustapha 1  · Mohamad S. AlSalhi 2,3  · Saradh Prasad 2,3 Received: 17 October 2018 / Accepted: 8 March 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract In this paper, the spectral and electrical properties of a conjugated polymer poly [(9, 9-dioctyl-2, 7-divinylenefuorenylene)- alt-co-(1, 4-phenylene)] (PFO–MEH–PPV) with poly[3-(2-ethyl-isocyanato-octadecanyl) thiophene] (PECOD) in thin flms have been studied. First, PFO–MEH–PPV and PECOD were dissolved in tetrahydrofuran and chloroform respectively for diferent concentrations. These solutions were deposited on glass substrates to form thin flms with diferent thicknesses. The absorbance and photoluminescence spectra for each individual pure polymer were recorded and contrasted with those for blended conjugated polymer’s flms to determine the efect of blending on the absorption and photoluminescence. Finally, we present a study on the processing and characterization of organic solar cells fabricated by spin coating pure PFO–MEH–PPV, PECOD and their blend as the organic active layer onto indium tin oxide layer (150 nm), followed by the evaporation of silver cathode (110 nm). The current–voltage characteristics of these cells were determined and external quantum efciency. Upon blending the two polymers in solid forms, it could be seen that the efciency (6.25%) for the cells based on a blend layer is higher than the ones without blending (4.4%). Finally, we demonstrated here that the combination/blending of conjugated polymers has resulted in optimized solar device function, with reasonably quantum efciency higher than 10%. 1 Introduction In the last two decades, organic conjugated polymers have been widely used in electronics and optoelectronics, includ- ing photovoltaic cells [1–5], thin flm transistors [6, 7], and light-emitting diodes (LEDs) [8–15]. Electroluminescence (EL) in the conjugated polymers was frst reported by Bur- roughes et al. in 1990 for the fabrication of LEDs [8]. Since then, many researchers have examined the morphology, physical, optical and photoelectric properties of the spin- coated emissive conjugated polymers [10, 11, 16–20]. For LED applications, the polymer used must have two basic characteristics: electrical conductivity (semiconducting polymer) and high photoluminescence (PL) efciency [21]. Thus, scientists have focused on improving the absorption and PL characteristics of the conjugated polymers in ultra- violet and visible ranges. To improve the performance, efciency, and reliability of optoelectronic devices, researchers have used diferent kinds of electrodes, inserted more layers between electrodes, and blended polymers to tune their physical properties [3, 5]. The resultant blend can have combined attractive features of the conjugated polymers or new properties that are not pre- sent in either of the polymers. Thus, this attractive approach of forming active semiconducting layers in the photovoltaic device by blending conjugated polymers can result in opti- mized device function, efciency and lifetime [1]. The recent progress made in improving and up-grading the efciency of organic solar cells based on conjugated pol- ymers was done by incorporating emissive materials, such as nanoparticles, quantum dots or graphene to the active layer of the devices based on conjugated polymers [22, 23]. According to Mustapha et al. the polymeric cell’s pho- toconductivity increases when electron transport materials ZnO nanoparticles are incorporated into the cells [23]. Dif- ferent materials such as quantum dots and graphene have * Nazir Mustapha nmmustapha@imamu.edu.sa 1 Department of Physics, College of Science, Imam Mohammad Ibn Saud Islamic University, P.O. Box 90950, Riyadh 11623, Saudi Arabia 2 Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia 3 Research Chair on Laser Diagnosis of Cancers, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia