Dr. Marwa Abd-Ellah

Silver nanowire (AgNW) networks have been widely touted as a promising material for transparent electrodes to replace indium tin oxide (ITO). Here we integrate polyurethane (PU) passivated AgNW electrodes into WO 3 /NiO electrochromic smart windows, placing particular focus on their NIR transparency. Experiments and modeling show that devices with NW electrodes permit more NIR radiation to transmit across the window compared to devices based on ITO. This is then shown to lead to a higher solar heat gain coefficient and lower U-factor, which is highly desirable in colder climates.

Electrochromic Smart Windows with High Near-Infrared Transparency Based on Passivated Silver Nanowire Electrodes
J Atkinson, M Abd-Ellah, IA Goldthorpe - 2The 23rd IEEE International Conference on Nanotechnology (IEEE-NANO 2023) 

Two new π-conjugated polymers with donor backbone and π-conjugated indolin-2-one side chains, PBDTTI and PBDTTIF, are designed and synthesized as wide bandgap donors for non-fullerene acceptor-based organic solar cells (OSCs). The monomers containing electron accepting indolin-2-one side chains, (Z)-3-((2,5-dibromothiophen-3-yl) methylene)-1-methylindolin-2-one (M1) and (Z)-3-((2,5-dibromothiophen-3-yl) methylene)-5-fluoro-1-methylindolin-2-one (M2), can be easily synthesized via Knoevenagel condensation between 2,5-dibromothiophene-3-carbaldehyde and 2-oxindole or 5-fluoro-2-oxindole, respectively. Stille coupling polymerization of the electron-donating benzodithiophene (BDT)-containing monomer 1,1′-[4,8-bis [5-(2-ethylhexyl)-2-thienyl]benzo [1,2-b:4,5-b′]dithiophene-2,6-diyl]bis [1,1,1-trimethylstannane] and M1 or M2 produced PBDTTI or PBDTTIF, respectively. The strong electron accepting π-conjugated 1-methylindolin-2-one and 5-fluoro-1-methylindolin-2-one side chains can achieve low-lying HOMO energy levels of −5.59 eV for PBDTTI and −5.60 eV for PBDTTIF, which is beneficial for realizing high open circuit voltage (VOC) of the resulting OSCs. On the other hand, since the electron acceptor units are on the side chains, the polymer backbone containing only electron donor units could maintain wide bandgaps of 1.91 eV and 1.89 eV for PBDTTI and PBDTTIF, respectively. When PBDTTI and PBDTTIF were used as donors and a small bandgap non-full acceptor ITIC as an acceptor, the resulting OSCs devices achieved VOC of 0.97 and 1.00 V, short circuit current densities (JSC) of 15.60 and 13.70 mAcm-2, and fill factors (FF) of 0.60 and 0.59, resulting in power conversion efficiencies of 8.00 and 7.70%, respectively.

Novel Wide Bandgap Benzodithiophene-based Polymer Donors with Electron-withdrawing Indolin-2-one Side Chains for Efficient Organic Solar Cells with a Large Open Circuit Voltage

W Li, M Abd-Ellah, , Y Li, Dyes and Pigments 197, 109876, 2023