03453nas a2200253 4500008004100000022001400041245009600055210006900151260000800220300001600228490000800244520261200252653001102864653001002875653001302885653001702898100002802915700002702943700002202970700002602992700003003018700002703048856012403075 2023 eng d a1932-744700aSteric and electronic effect in unsymmetrical squaraine dyes for dye-sensitized solar cells0 aSteric and electronic effect in unsymmetrical squaraine dyes for cNOV a22473-224880 v1273 a

Functionalizing the light harvesting sensitizers with additional electron-donating or -withdrawing groups is a potential approach to modulate the photophysical and electrochemical properties which in-turn optimizes the driving force associated with the charge injection and dye-regeneration processes at the dye-TiO2/electrolyte interface and the photovoltaic device performance in dye-sensitized solar cells (DSSCs). Furthermore, modulated electronic levels of the dyes provide an opportunity to reduce the overpotential associated with the dye-regeneration process and make the dye-TiO2 interface compatible with various electrolytes. Furthermore, an in-built steric feature by means of introducing linear/branched alkyl groups in the sensitizer is important in controlling the aggregation of dyes on the TiO2 surface. Hence, to integrate both steric and electronic properties, a series of alkyl group-wrapped unsymmetrical squaraine dyes (SQ-X) with electron-donating and -withdrawing groups have been designed, synthesized, and utilized for DSSC device fabrication. These dyes are functionalized with alkyl groups at both sp(3)-C and N-atoms of the indoline donor moiety at the nonanchoring side to have a similar steric feature. Photophysical and electrochemical studies revealed that the HOMO and LUMO energy levels of the SQ-X series of dyes have been modulated systematically with sufficient driving forces for both charge injection and dye-regeneration processes with iodolyte (I-/I-3(-)) electrolyte. In the presence of electron-donating groups in SQ-X (where X = -NPh2 and -OMe), the HOMO energy levels are less positive than SQ-H, whereas the presence of electron-withdrawing groups such as -CO2Me, -CN, and -NO2 pushed the HOMO energy levels toward more positive potentials. Enhanced photovoltaic performances have been obtained for the dyes containing electron-donating groups, where the dye with the -NPh2 group showed a maximum of eta 7.03% (V-OC 708 mV, J(SC) 13.16 mA cm(-2), and ff 78%). The dye with the strong electron-withdrawing group -NO2 showed an efficiency of 1.49% (V-OC = 634 mV, J(SC) = 3.13 mA cm(-2), and ff 75%). As the dyes with the electron-withdrawing group possess deep positive HOMO energy levels, the DSSC device characterization has been investigated with the Cu+/2+ redox shuttle. The reduced device performance of electron-withdrawing-group-containing dyes is due to the unfavored charge distribution in the LUMO compared to the presence of electron-donating-group-containing dyes, and it was supported by the difference in the charge injection efficiency.

10acobalt10aDonor10aDynamics10aOrganic dyes1 aNawghare, Indrajeet, S.1 aSingh, Ambarish, Kumar1 aMaibam, Ashakiran1 aKrishnamurty, Sailaja1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/steric-and-electronic-effect-unsymmetrical-squaraine-dyes-dye-sensitized-solar-cells02341nas a2200265 4500008004100000022001400041245011900055210006900174260000900243300001100252490000800263520140100271653002401672653001601696653003001712653002801742653001801770100002801788700003101816700001701847700002601864700003001890700002701920856012801947 2025 eng d a1010-603000aFar-red active squaraine dye-sensitized photoanode for dye-sensitized solar cells with a copper (II/I) electrolyte0 aFarred active squaraine dyesensitized photoanode for dyesensitiz cFEB  a1160860 v4593 a

In dye-sensitized solar cells (DSSC), controlling the dye-aggregation on TiO2 and charge recombination between electrons present in TiO2 and electrolyte can be achieved by wrapping the long alkyl groups around the dye structure and further introducing bulky donor on the dye is a potential approach to enhance both the open-circuit potential and short-circuit current parameters. Additionally, bulky donor containing dye structures modulates the photophysical and electrochemical properties of the sensitizer which helps reducing the over potentials required for the dye regeneration process by utilizing a multidentate ligand containing [Cu(tme)]2+/+ and I- /I3redox electrolytes. Hagfeldt donor appended far-red NIR active unsymmetrical squaraine dye (SQ-HF) has been designed, synthesized, and characterized. SQ-HF dye showed an intense absorption at 676 nm (epsilon 1.7 x 105 M- 1cm- 1). Photophysical and electrochemical studies indicated that the LUMO and HOMO energy levels of the SQ-HF dye were suited for charge injection (from the LUMO of the dye to the conduction band of TiO2) and dyeregeneration processes, respectively. The DSSC device efficiency of 5.15 % (JSC of 10.83 mA/cm2 and VOC of 0.690 V) has been achieved for SQ-HF dye by utilizing a literature reported [Cu(tme)]2+/+ and 4.11 % (JSC of 8.74 mA/cm2 and VOC of 0.702 V) in I- /I3- redox shuttles, respectively.

10aaggregation of dyes10aBulky donor10adye-sensitized solar cell10aPhotocurrent generation10asquaraine dye1 aNawghare, Indrajeet, S.1 aDeshmukh, Shivdeep, Suresh1 aJoshi, Krati1 aKrishnamurty, Sailaja1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/far-red-active-squaraine-dye-sensitized-photoanode-dye-sensitized-solar-cells-copper-iii02157nas a2200181 4500008004100000022001400041245015100055210006900206260000800275300001400283490000700297520144000304100002001744700002801764700002701792700002601819856013001845 2025 eng d a0024-929700aSquaraine dyes as efficient photoredox catalysts for PET-RAFT polymerization in batch and flow modes accelerated by suppression of dye aggregation0 aSquaraine dyes as efficient photoredox catalysts for PETRAFT pol cMAR a2850-28590 v583 a

Organic photoredox catalysts (PCs) based on squaraine dyes are investigated for photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization under visible-light (lambda max = 485 nm) irradiation in the presence of triethylamine that suppresses self-aggregation of dye and accelerates the polymerization. Several commonly used PCs are also screened, and self-aggregation is found to be reduced with triethylamine, thus providing a simple and effective approach to reduce aggregation of PCs. There is no induction period, and total polymerization time is shorter for squaraine dye PCs than for reported PCs under similar conditions. The photocatalyst system is amenable to polymerization by using different RAFT agents. Methyl methacrylate and a range of functional methacrylates are polymerized with good control over molecular weight and narrow dispersity in a first-order reaction with a random switch ``ON-OFF'' of the light source and even without an inert atmosphere. The mechanism of polymerization without and with requirement of triethylamine is elucidated using control experiments and found to be an oxidative and reductive electron transfer, respectively. A series of diblock and random copolymers of methyl methacrylate with methacrylate monomers are synthesized. Controlled polymerization is also demonstrated using a continuous-flow method and in an aqueous medium.

1 aPatil, Anil, M.1 aNawghare, Indrajeet, S.1 aNithyanandhan, Jayaraj1 aAmbade, Ashootosh, V. uhttps://library.ncl.res.in/content/squaraine-dyes-efficient-photoredox-catalysts-pet-raft-polymerization-batch-and-flow-modes02916nas a2200301 4500008004100000022001400041245015000055210006900205260000800274300001400282490000600296520186400302653003302166653001802199653002702217653001302244653001802257653002102275100002002296700002802316700001602344700002502360700002302385700002902408700002702437700002602464856012402490 2026 eng d a2637-610500apH-Responsive and antimicrobial polymer synthesis in continuous flow and effect of pendant alkylamine on the squaraine dye photocatalyst activity0 apHResponsive and antimicrobial polymer synthesis in continuous f cMAY a6287-63000 v83 a

pH-responsive and antimicrobial polymers were synthesized by photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization under blue light (lambda max = 485 nm) using a scalable continuous flow method. The effect of pendant alkylamino groups with different alkyl substituents on methacrylate monomers under blue light is investigated in the absence of a tertiary alkylamine reagent and in the presence of cyanopentanoic acid dithiobenzoate and 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl]pentanoic acid as RAFT agents. The rate of polymerization is found to vary with the size of the alkyl chain and with the tertiary, secondary, or quaternary nature of the amino group. The ability of pendant alkylamino groups to transfer electrons to the photocatalyst is shown using cyclic voltammetry and fluorescence quenching experiments; the tendency to suppress dye aggregation is observed using UV-vis spectroscopy; and the rates of polymerization could be correlated with the trend in these results. The mechanism of polymerization is proposed to follow a reductive or oxidative electron transfer pathway depending on the nature of the pendant group. Statistical and diblock copolymers with 2-hydroxyethyl methacrylate are synthesized in batch and continuous flow processes with a comparative study of kinetics in the two methods. The synthesis of high-molecular-weight homopolymer (55,000 g/mol) and statistical copolymer (85,000 g/mol) of N,N-diisopropylaminoethyl methacrylate is shown in continuous flow. The solution self-assembly of diblock copolymers is studied, and the pH-responsive morphology change leading to disassembly is shown. The antimicrobial properties of polymers with a quaternary ammonium pendant group are evaluated. The thermal degradation of statistical copolymers is analyzed.

10aalkylaminoethyl methacrylate10aAntimicrobial10acontinuous flowprocess10aPET-RAFT10apH-responsive10aself-aggregation1 aPatil, Anil, M.1 aNawghare, Indrajeet, S.1 aSiby, Jesna1 aBankar, Priyanka, M.1 aDastager, Syed, G.1 aRode, Chandrashekhar, V.1 aNithyanandhan, Jayaraj1 aAmbade, Ashootosh, V. uhttps://library.ncl.res.in/content/ph-responsive-and-antimicrobial-polymer-synthesis-continuous-flow-and-effect-pendant