@article{babu_elsherbiny_cheema_el-shafei_adhikari_2016, title={Highly efficient panchromatic dye-sensitized solar cells: Synergistic interaction of ruthenium sensitizer with novel co-sensitizers carrying different acceptor units}, volume={132}, ISSN={["1873-3743"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84969544853&partnerID=MN8TOARS}, DOI={10.1016/j.dyepig.2016.05.016}, abstractNote={Herein, we report the molecular design, synthesis and photovoltaic performance studies of three new organic co-sensitizers, N1-3 carrying indole and thiophene units linked to different acceptors/anchoring groups, as co-adsorbents for dye sensitized solar cells. We present the role of anchoring/acceptor units on co-sensitization properties N1-3. Their photo-physical and electrochemical results along with molecular geometry, obtained from Density Functional Theory are utilized to rationalize the influence of co-sensitizer structures on photovoltaic properties for DSSCs. We have shown that, the co-sensitization effect is profoundly dependent upon the anchoring/acceptor unit in the co-adsorbents. Among them, N3 containing 4-aminobenzoic acid shows promising co-sensitization results and exhibits an enhanced efficiency of 9.26%, when co-sensitized with a ruthenium dye, HD-14. Further, the study highlights the importance of molecular matching between the sensitizer and co-sensitizer in enhancing the efficiency. Furthermore, vertical electronic excitations are calculated using time dependent density functional theory studies.}, journal={DYES AND PIGMENTS}, author={Babu, Dickson D. and Elsherbiny, Dalia and Cheema, Hammad and El-Shafei, Ahmed and Adhikari, Airody Vasudeva}, year={2016}, month={Sep}, pages={316–328} }
 @article{babu_cheema_elsherbiny_el-shafei_adhikari_2015, title={Molecular Engineering and Theoretical Investigation of Novel Metal-Free Organic Chromophores for Dye-Sensitized Solar Cells}, volume={176}, ISSN={["1873-3859"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84938295841&partnerID=MN8TOARS}, DOI={10.1016/j.electacta.2015.07.079}, abstractNote={In this work we report design and synthesis of three new metal free D-D–A–π–A type dyes (E1-3) with different acceptor/anchoring groups, as effective sensitizers for nanocrystalline titanium dioxide based dye sensitized solar cells. All the three dyes carry electron donating methoxy group as an auxiliary and indole as a principal donor, cyanovinylene as an auxiliary acceptor and thiophene as a π-spacer. Whereas, cyanoacetic acid, rhodanine-3-acetic acid and 4-aminobenzoic acid perform as acceptor/anchoring moieties, respectively in the dyes E1-3. Though the dye containing 4-aminobenzoic acid unit (E3) exhibits comparatively lower λmax, it shows the highest power conversion efficiency arising from the higher electron life time and good light-harvesting capability. The DFT studies reveal a better charge separation between the HOMO and LUMO levels of E3, further substantiating the experimental results. Among the three dyes, E3 shows the best photovoltaic performance with short-circuit current density (Jsc) of 9.35 mA cm−2, open-circuit voltage (Voc) of 620 mV and fill factor (FF) of 0.71, corresponding to an overall conversion efficiency of 4.12% under standard global AM 1.5G.}, journal={ELECTROCHIMICA ACTA}, author={Babu, Dickson D. and Cheema, Hammad and Elsherbiny, Dalia and El-Shafei, Ahmed and Adhikari, Airody Vasudeva}, year={2015}, month={Sep}, pages={868–879} }
 @article{el-sherbiny_cheema_el-essawy_abdel-megied_el-shafei_2015, title={Synthesis and characterization of novel carbazole-based terpyridyl photosensitizers for dye-sensitized solar cells (DSSCs)}, volume={115}, ISSN={["1873-3743"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84922373450&partnerID=MN8TOARS}, DOI={10.1016/j.dyepig.2014.12.009}, abstractNote={Two novel terpyridyl-based Ru(II) complexes, DH-1 and DH-2, were synthesized and characterized as photosensitizers for dye-sensitized solar cells. To enhance the thermal and photostability, a strong electron donor bidentate carbazole-based ancillary ligand was molecularly engineered and used to replace two monodentate labile isothiocyanates. Photovoltaic characterizations, I–V curve and IPCE, of DH-1 and DH-2 were carried out in presence of deoxycholic acid as an additive to determine the best device working conditions. DH-1 showed IPCE of 45% at 540 nm, short circuit photocurrent density (Jsc) of 11.69 mA cm−2, open circuit photovoltage (Voc) of 0.64 V, fill factor of 0.63, producing an overall conversion efficiency (η) of 4.68%, where DH-2 showed IPCE of 45% at 540 nm, Jsc of 10.90 mA cm−2, Voc of 0.59 V and FF of 0.59, which translated into η of 3.82%. DFT calculations rationalized the light harvesting efficiency and charge separation of why DH-1 > DH-2.}, journal={DYES AND PIGMENTS}, author={El-Sherbiny, Dalia and Cheema, Hammad and El-Essawy, Farag and Abdel-Megied, Ahmed and El-Shafei, Ahmed}, year={2015}, month={Apr}, pages={81–87} }