Browsing by Author "Malik, M. I."

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    Fabrication of inverted organic solar cells on stainless steel substrate with electrodeposited and spin coated ZnO buffer layers
    (Journal of Polymer Engineering, 2022) Namawardana, D. G. K. K.; Wanigasekara, R. M. G.; Wanninayake, W. T. M. A. P. K.; Jayathilaka, K. M. D. C.; Wijesundera, R. P.; Siripala, W.; Malik, M. I.
    Polymer based organic solar cells (OSCs) are of tremendous interest as suitable candidates for producing clean and renewable energy in recent years. In this study, inverted OSCs on stainless steel (SS) substrate with zinc oxide (ZnO) as the electron selective transport layer (ESTL), are investigated, occupying bulk heterojunction blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl- C61-butyric acid methyl ester (PCBM) as the active material and poly-(4,3-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the hole transport layer (HTL). The device structure is SS/ZnO/P3HT:PCBM/PEDOT:PSS/Au. ZnO films are prepared by spin coating and electrodeposition techniques, followed by annealing under ambient conditions. The insertion of ZnO layer between the SS substrate and active layer has improved short-circuit current ( Jsc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) compared to those of the reference cell without ZnO layer, achieving the highest efficiency of 0.66% for the device with spin coated ZnO from sol–gel technique. This enhancement can be attributed to the effective electron extraction and the increased crystallinity of ZnO after annealing treatments at higher temperatures as further confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses.
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    Molecular tailoring of donor and acceptor materials of organic solar cells for improvement of their optoelectronic properties
    (Materials Science in Semiconductor Processing, 2022) Ansari, M. A.; Hafeez, A.; Mustafa, M.; Wijesundera, R. P.; Malik, M. I.
    Improvement in the efficiency of organic solar cell (OSC) is one of the hot topics of the modern-day research. Despite environment friendliness and several other practical advantages, the power conversion efficiency (PCE) of OSC has not yet achieved the levels of the commercial inorganic solar cells. In this context, molecular tailoring of the donor and acceptor materials can help in alignment of the energy levels in order to improve PCE. In this study, we demonstrate the introduction of different functional groups on the most widely used donor and acceptor materials namely poly(3-hexylthiophene) (P3HT) and fullerene, respectively. P3HT was successfully converted into poly(4-bromo-3-hexylthiophene), poly(4-chloro-3-hexylthiophene), and poly(3-hexyl-4-nitrothiophene) through bromination, chlorination, and nitration reactions, respectively. Similarly, fullerene was converted into phenyl-C61-pentanoic acid methyl ester, phenyl-C61-pentanoic acid, and methyl-2-C61 propionate. The success of different modifications on P3HT and fullerene was monitored by 1H NMR spectroscopy. Finally, the optoelectronic properties after the above-mentioned modifications were evaluated by UV–Vis spectroscopy and cyclic voltammetry.