01749nas a2200289 4500008004100000022001400041245012700055210006900182260007100251300001400322490000600336520071700342653002101059653002001080653003101100653002101131653001701152100001801169700001601187700002001203700002101223700001701244700002201261700001901283700002501302856013201327 2009 eng d a1944-824400aEnhanced conversion efficiency in dye-sensitized solar cells based on hydrothermally synthesized TiO2-MWCNT nanocomposites0 aEnhanced conversion efficiency in dyesensitized solar cells base a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a2030-20350 v13 a

A 50 % enhancement in the conversion efficiency (4.9-7.37 %) is realized in dye-sensitized solar cells Using hydrothermally synthesized TiO2-multiwalled carbon nanotube (MWCNT) nanocomposites as compared to hydrothermally synthesized TiO2 without MWCNT and Degussa P25. Several characterizations have been employed to reveal the nature of the modification imparted to the MWCNTs under hydrothermal processing conditions and the resulting TiO2-MWCNT conjugation through -COOH groups. Efficient charge transfer In the nanocomposite and efficient electron transport by MWCNT (significantly higher Incident-photon-to-current conversion efficiency) are suggested to be the possible reasons for the enhancement.

10aCarbon nanotubes10acharge transfer10aDye-sensitized solar cells10aHybrid composite10ahydrothermal1 aMuduli, Subas1 aLee, Wonjoo1 aDhas, Vivek, V.1 aMujawar, Sarfraj1 aDubey, Megha1 aVijayamohanan, K.1 aHan, Sung-Hwan1 aOgale, Satishchandra uhttps://library.ncl.res.in/content/enhanced-conversion-efficiency-dye-sensitized-solar-cells-based-hydrothermally-synthesized-001886nas a2200253 4500008004100000022001400041245008200055210006900137260010600206300001400312490000700326520094000333653003101273653004301304653001701347100002001364700001801384700002401402700002001426700002301446700002001469700002901489856011401518 2011 eng d a0038-092X00aEnhanced DSSC performance with high surface area thin anatase TiO2 nanoleaves0 aEnhanced DSSC performance with high surface area thin anatase Ti aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN a1213-12190 v853 a

Thin anatase TiO2 nanoleaves (NLs) with high surface area (similar to 93 m(2)/g) are synthesized by hydrothermal route and dye-sensitized solar cells (DSSC) made using such NLs are compared with those made with hydro-thermally synthesized TiO2 nanoparticles and the Degussa P25 powder. The NLs-based DSSCs show increment of 16% and 24% in the total conversion efficiency over the cells made with NPs and P25 respectively. Interestingly, the highest increment in the conversion efficiency (similar to 35%) is achieved for cells made using a 50:50 (wt/wt) mixture of NLs and NPs. In this case the dye loading is found to be >50% higher than the case of NP films. Moreover the DC resistance of diffusion of I-3(-) in electrolyte (as revealed by the electrochemical impedance spectroscopy) is substantially lower than the NP film case, other cell parameters being nominally comparable. (C) 2011 Elsevier Ltd. All rights reserved.

10aDye-sensitized solar cells10aElectrochemical impedance spectroscopy10ahydrothermal1 aDhas, Vivek, V.1 aMuduli, Subas1 aAgarkar, Shruti, A.1 aRana, Abhimanyu1 aHannoyer, Beatrice1 aBanerjee, Rahul1 aOgale, Satishchandra, B. uhttps://library.ncl.res.in/content/enhanced-dssc-performance-high-surface-area-thin-anatase-tio2-nanoleaves-001836nas a2200277 4500008004100000022001400041245009400055210006900149260010600218300001400324490000700338520084400345653001701189653000701206653003101213653002101244653001701265100001801282700002001300700002001320700002201340700002501362700001701387700002901404856012501433 2012 eng d a0038-092X00aTiO2-Au plasmonic nanocomposite for enhanced dye-sensitized solar cell (DSSC) performance0 aTiO2Au plasmonic nanocomposite for enhanced dyesensitized solar  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAY a1428-14340 v863 a

Anatase TiO2 nanoparticles dressed with gold nanoparticles were synthesized by hydrothermal process by using mixed precursor and controlled conditions. Diffused Reflectance Spectra (DRS) reveal that in addition to the expected TiO2 interband absorption below 360 nm gold surface plasmon feature occurs near 564 nm. It is shown that the dye sensitized solar cells made using TiO2-Au plasmonic nanocomposite yield superior performance with conversion efficiency (CE) of similar to 6% (no light harvesting), current density (J(SC)) of similar to 13.2 mA/cm(2), open circuit voltage (V-oc) of similar to 0.74 V and fill factor (FF) 0.61; considerably better than that with only TiO2 nanoparticles (CE similar to 5%, J(SC) similar to 12.6 mA/cm(2), V-oc similar to 0.70 V, FF similar to 0.56). (C) 2012 Elsevier Ltd. All rights reserved.

10aAnatase TiO210aAu10aDye-sensitized solar cells10aHybrid composite10ahydrothermal1 aMuduli, Subas1 aGame, Onkar, S.1 aDhas, Vivek, V.1 aVijayamohanan, K.1 aBogle, Kashinath, A.1 aValanoor, N.1 aOgale, Satishchandra, B. uhttps://library.ncl.res.in/content/tio2-au-plasmonic-nanocomposite-enhanced-dye-sensitized-solar-cell-dssc-performance-002185nas a2200241 4500008004100000022001400041245015900055210006900214260005700283300000800340490000700348520129500355653000801650653003101658653001701689653002001706653001101726100002401737700002001761700001701781700002301798856012201821 2016 eng d a1610-294000aDoes the position of the electron-donating nitrogen atom in the ring system influence the efficiency of a dye-sensitized solar cell? A computational study0 aDoes the position of the electrondonating nitrogen atom in the r a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcJUN a1210 v223 a

We have reported a number of new metal-free organic dyes (2-6) that have cyclic asymmetric benzotripyrrole derivatives as donor groups with peripheral nitrogen atoms in the ring, fluorine and thiophene groups as pi-spacers, and a cyanoacrylic acid acceptor group. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were employed to examine the influence of the position of the donor nitrogen atom and pi-conjugation on solar cell performance. The calculated electron-injection driving force (Delta G(inject)), electron-regeneration driving force (Delta G(regen)), light-harvesting efficiency (LHE), dipole moment (mu(normal)), and number of electrons transferred (Delta q) indicate that dyes 3, 4, and 6 have significantly higher efficiencies than reference dye 1, which exhibits high efficiency. We also extended our comparison to some other reported dyes, 7-9, which have a donor nitrogen atom in the middle of the ring system. The computed results suggest that dye 6 possesses a higher incident photon to current conversion efficiency (IPCE) than reported dyes 7-9. Thus, the use of donor groups with peripheral nitrogen atoms appears to lead to more efficient dyes than those in which the nitrogen atom is present in the middle of the donor ring system.

10aDFT10aDye-sensitized solar cells10aOrganic dyes10aPosition effect10aTD-DFT1 aBiswas, Abul, Kalam1 aBarik, Sunirmal1 aDas, Amitava1 aGanguly, Bishwajit uhttps://library.ncl.res.in/content/does-position-electron-donating-nitrogen-atom-ring-system-influence-efficiency-dye02581nas a2200265 4500008004100000022001400041245010200055210006900157260000800226300001600234490000700250520165100257653003101908653002401939653003001963653001901993653003002012653001902042100001802061700002402079700003902103700001902142700002702161856012702188 2018 eng d a1944-824400aFused fluorenylindolenine-donor-based unsymmetrical squaraine dyes for dye-sensitized solar cells0 aFused fluorenylindoleninedonorbased unsymmetrical squaraine dyes cAUG a26335-263470 v103 a

A series of four unsymmetrical squaraine dyes, XSQ1-4, were synthesized using a fused fluorenylindolenine-based donor unit for dye-sensitized solar cells (DSSCs). The fused structure of fluorenylindolenine helped in moving the absorption toward the near-infrared (NIR) region, and the two sp(3)-C centers available on this donor were utilized to incorporate out-of-plane alkyl chains in opposite directions to control the dye-dye interactions on the TiO2 surface. High extinction coefficient (epsilon >= 10(5) M-1 cm(-1)) for absorbing NIR photons and suitable highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels with respect to the conduction band of TiO2 and electrolyte for charge injection and dye regeneration processes, respectively, make these dyes potential sensitizers for DSSCs. Introduction of branched alkyl groups in the pi-framework helped in controlling dye aggregation to reduce exciton quenching and assisted in TiO2 surface passivation to avoid the charge recombination process. Furthermore, having a naphthyl group on the indole part of the anchoring group containing segment helped to red-shift the absorption spectrum of dyes 15 nm toward the NIR region (XSQ3-4). Among all of the dyes under investigation, XSQ2 gave the best photovoltaic performance, having a short-circuit current density (J(SC)) of 13.99 mA cm(-2), open -circuit voltage (V-OC) of 0.66 V, and a fill factor (ff) of 0.71, with a device performance (eta) of 6.57%. Electrochemical impedance spectroscopy revealed higher electron lifetime on TiO2 for XSQ2, which helps to avoid the charge recombination process.

10aDye-sensitized solar cells10afluorenylindolenine10aH- and J-type aggregation10aNIR absorption10aout-of-plane alkyl groups10asquaraine dyes1 aBisht, Rajesh1 aSudhakar, Vediappan1 aKavungathodi, Munavvar, Fairoos Me1 aKarjule, Neeta1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/fused-fluorenylindolenine-donor-based-unsymmetrical-squaraine-dyes-dye-sensitized-solar02335nas a2200241 4500008004100000022001400041245011500055210006900170260000800239300001400247490000600261520145000267653002301717653002001740653003101760653003201791653002601823100002801849700003901877700002701916700002701943856012301970 2019 eng d a2574-096200api-Extended cis-configured unsynimetrical squaraine dyes for dye-sensitized solar cells: panchromatic response0 apiExtended cisconfigured unsynimetrical squaraine dyes for dyese cDEC a8464-84720 v23 a

{Light absorbing sensitizer is the heart of the third generation photovoltaic technologies such as dye sensitized solar cells. Despite possessing large extinction coefficients for the metal-free organic dyes, the light harvesting efficiency is limited with the narrow absorption 20 profile in either visible or NIR regions of the solar spectrum. Though monolayer formation of organic sensitizers on semiconducting metal oxide surface leads to dye-dye interaction that leads to broadening the absorption profile, the contribution of the aggregated state to the power conversion process is found out to be poor. Here, we have engineered far-red active pi-extended cis-configured unsymmetrical squaraine dyes with carboxylic acid and cycnoacetic acid as anchoring groups with controlled aggregation and panchromatic light absorption by including the steric and electronic factors. The presence of sp(3)-C (out-of-plane) and N-alkyl (in-plane) groups played an important role in modulating the assembly of the dyes on the TiO2 electrode; the cis-squaraine unit helps to extend the conjugation in the NIR region besides enhancing the visible transition and the incident photon-to-current conversion efficiency profile that showed the importance of anchoring groups for the panchromatic response. Dye PSQ10 showed solar-to electric conversion with an onset of 850 nm with the device performance of 7.0% (V-oc = 0.581 V, J(sc) = 17.06 mA/cm(2)

10acis-squaraine dyes10aDye aggregation10aDye-sensitized solar cells10aextended far-red absorption10apanchromatic response1 aPunitharasu, Vellimalai1 aKavungathodi, Munavvar, Fairoos Me1 aSingh, Ambarish, Kumar1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/pi-extended-cis-configured-unsynimetrical-squaraine-dyes-dye-sensitized-solar-cells03102nas a2200229 4500008004100000022001400041245017500055210006900230260000800299300001400307490000700321520219200328653002302520653002102543653002502564653003102589653002902620100002702649700003902676700002702715856013002742 2020 eng d a1944-824400aAlkyl-group-wrapped unsymmetrical squaraine dyes for dye-sensitized solar cells: branched alkyl chains modulate the aggregation of dyes and charge recombination processes0 aAlkylgroupwrapped unsymmetrical squaraine dyes for dyesensitized cJAN a2555-25650 v123 a

Electron transfer processes at the interfaces dictate the factors that improve the photovoltaic parameters, such as open-circuit voltage (V-oc) and short-circuit current (J(sc)), of a dye-sensitized solar cell device, besides selection of a set of suitable anode, dye, electrolyte, and cathode materials. An inefficient charge injection process at the dye-TiO2 interface and charge recombination at the TiO2-dye/electrolyte interface have detrimental effects on improving both J(sc) and V-oc. Hence, tailoring the factors that govern the improvement of J(sc) and V-oc will be an ideal approach to get the desired sensitizers with good device efficiencies. Squaraines are far-red-active zwitterionic dyes and have a high molar extinction coefficient along with unique aggregation properties due to the large dipole moment associated with them. Here, we report a series of unsymmetrical squaraine dyes, SQS1 to SQS6, with systematic variation of alkyl groups at the sp(3)-C and N-atoms of the indoline unit that is away from the anchoring group to control the dye-dye interactions on the TiO2 surface. The branched alkyl groups help in modulating the self-assembly of sensitizers on the TiO2 surface, besides passivating the surface that helps avoid the charge recombination processes. Light harvesting efficiency and cyclic voltammetry studies of dye-sensitized TiO2 electrodes indicate that the aggregation and charge hopping process between the dye molecules can be modulated, respectively, by systematically increasing the number of carbon atoms in the alkyl groups. Such a variation in the branched alkyl group helps enhance V-oc from 672 (SQS1) to 718 mV (SQS6) and J(sc) from 7.95 (SQS1) to 12.22 mA/cm(2) (SQS6), with the device efficiency ranging from 3.82% to 6.23% without any coadsorbent. Dye SQS4 achieves the highest efficiency of 7.1% (V-oc = 715 mV, J(sc) = 13.05 mA/cm(2)) with coadsorbent chenodeoxycholic acid (CDCA) using an iodine (I-/I-3(-)) electrolyte compared to its analogues. An analysis of the incident photon-to-current efficiency profiles indicates that the major contribution to photocurrent generation is from the aggregated squaraine dyes on TiO2.

10aaggregation of dye10acharge injection10acharge recombination10aDye-sensitized solar cells10aunsymmetrical squaraines1 aSingh, Ambarish, Kumar1 aKavungathodi, Munavvar, Fairoos Me1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/alkyl-group-wrapped-unsymmetrical-squaraine-dyes-dye-sensitized-solar-cells-branched-alkyl02005nas a2200229 4500008004100000022001400041245012300055210006900178260000800247300001200255490000600267520117600273653002201449653003101471653003001502653001401532653002701546100002401573700002301597700002601620856012901646 2020 eng d a2637-611300aNanoporous reduced graphene oxide and polymer composites as efficient counter electrodes in dye-sensitized solar cells0 aNanoporous reduced graphene oxide and polymer composites as effi cMAR a626-6340 v23 a

The introduction of an efficient and precious platinum (Pt) free counter electrode (CE) for dye-sensitized solar cells (DSSCs) is an important aspect to address. In this report, we have employed nanoporous reduced graphene oxide (PG) containing PEDOT:PSS-PG composite on FTO substrate as CEs, which have shown excellent diffusion of I-3(-), remarkable photocatalytic activity, and better device performance along with desired stability. The investigated cathode material has been prepared by mixing PGs and highly conducting PEDOT:PSS. Experimental measurements and analyses such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and so on indicate that PEDOT:PSS-PG is a promising cathode material for a Pt-free CE in DSSCs. EIS indicates that the PEDOT:PSS-PGs have lower interfacial charge-transfer resistance because of their high electrical conductivity and superior electrocatalytic activity. The achieved photoconversion efficiency (eta) of a DSSC employing the Pt-free PEDOT:PSS-PG/FTO CE is 9.57%, which is found to be comparable to that of Pt/FTO CE based DSSC (9.64%) under a simulated solar light illumination of 100 mW/cm(2).

10acounter electrode10aDye-sensitized solar cells10aelectrocatalytic activity10aPEDOT:PSS10aReduced graphene oxide1 aSudhakar, Vediappan1 aSingh, Anup, Kumar1 aChini, Mrinmoy, Kumar uhttps://library.ncl.res.in/content/nanoporous-reduced-graphene-oxide-and-polymer-composites-efficient-counter-electrodes-dye02669nas a2200229 4500008004100000022001400041245017400055210006900229260000800298300001400306490000600320520174000326653003102066653004102097653003502138653002702173653003402200653002002234100002702254700002702281856013102308 2022 eng d a2574-096200aIndoline-based donor-pi-acceptor visible-light responsive organic dyes for dye-sensitized solar cells: co-sensitization with squaraine dye for panchromatic IPCE response0 aIndolinebased donorpiacceptor visiblelight responsive organic dy cFEB a1858-18680 v53 a

A series of metal-free indoline-based donor-pi-acceptor (D-pi-A) visible-light active organic dyes, where an indoline unit wrapped with alkyl or alkyl and glycolic (TEG) groups is used as a donor, a mono- or bi-thiophene unit is used as a pi-spacer, and cyanoacrylic acid acts as an acceptor unit, have been designed and synthesized for dye-sensitized solar cell (DSSC) application. These dyes showed three absorption bands in a dichloromethane solution: the first and second transitions are observed in the UV (337-385 nm) and visible (477-514 nm) regions and correspond to pi-pi* and intramolecular charge transfer (ICT) transition, respectively, whereas the third absorption band obtained in the near-IR (629-758 nm) region has been observed for the first time for a D-pi-A type dye architecture. Furthermore, the ICT transition band for AKT dyes showed negative solvatochromism with increasing polarity of solvents. Photovoltaic characterizations for AKT dyes have been systematically studied with a cobalt electrolyte to evaluate the effect of thiophene incorporation and alkyl group substitution by the TEG group on the DSSC device performance. Here, AKT2 showed the highest DSSC efficiency of 3.16% with V-OC of 0.680 V and J(SC) of 6.24 mA/cm(2) without chenodeoxycholic acid (CDCA) in the AKT dye series, whereas DSSC efficiencies for AKT dyes were not affected much upon further addition of CDCA. Furthermore, AKT dyes were co-sensitized with a complementary optical responsive indoline-based SQS4 dye and showed enhanced efficiency. The combination of AKT2/SQS4 dyes with a ratio of 1:1 showed a maximum of 5.20% co-sensitized solar cell efficiency compared to other dye combinations with the cobalt electrolyte.

10aDye-sensitized solar cells10aindoline-based donor-pi-acceptor dye10aintramolecular charge transfer10ametal-free organic dye10apanchromatic-light absorption10aSolvatochromism1 aSingh, Ambarish, Kumar1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/indoline-based-donor-pi-acceptor-visible-light-responsive-organic-dyes-dye-sensitized-solar02030nas a2200253 4500008004100000022001400041245010900055210006900164260000800233490000600241520111800247653002201365653002701387653003101414653001701445653003201462100002701494700002401521700003401545700001801579700003001597700002701627856012201654 2023 eng d a2367-093200aModular TiO2-squaraine dyes/electrolyte interface for dye-sensitized solar cells with cobalt electrolyte0 aModular TiO2squaraine dyeselectrolyte interface for dyesensitize cAPR0 v73 a

Strategies to diminish both charge recombination and aggregation of dyes on the photoanode by functionalizing the sensitizer with alkyl groups is the best approach to achieve high dyesensitized solar cell (DSSC) efficiency. Development of such a photoanode with NIR-active dyes which is compatible with a cobalt electrolyte is important to enhance the photovoltaic performance. In this report, alkyl-group-wrapped donor-acceptor-donor (D-A-D) based unsymmetrical squaraine dyes have been used for DSSC device characterization with a cobalt electrolyte. Surface passivation of photoanode was varied systematically by the extent of functionalization with alkyl groups to avoid charge recombination. DSSC device performance of 5.92% was achieved for an alkyl-group-wrapped squaraine dye with a cobalt electrolyte. Hence, appending the alkyl groups on the donor unit of squaraine dyes helps passivating the photoanode, whereas introducing hydrophilic groups provides a leaky surface where oxidized electrolyte species reach the titanium-metal-oxide surface which promotes the charge recombination process.

10acounter-electrode10aDSSC device efficiency10aDye-sensitized solar cells10aElectrolytes10aunsymmetrical squaraine dye1 aSingh, Ambarish, Kumar1 aSudhakar, Vediappan1 aJavaregowda, Bharathkumar, H.1 aBisht, Rajesh1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/modular-tio2-squaraine-dyeselectrolyte-interface-dye-sensitized-solar-cells-cobalt01964nas a2200253 4500008004100000022001400041245011800055210006900173260000800242490000600250520107500256653002001331653001901351653003101370653002501401653001901426100001801445700002701463700001701490700001701507700003001524700002701554856012901581 2023 eng d a2367-093200aVisible-light-active unsymmetrical squaraine dyes with 1 V of open-circuit voltage for dye-sensitized solar cells0 aVisiblelightactive unsymmetrical squaraine dyes with 1 V of open cMAY0 v73 a

A series of alkyl-group-functionalized, aniline- and indoline-donor-based, unsymmetrical visible-light-active squaraine dyes, AM1-3, were designed and synthesized. Dye-sensitized solar cell (DSSC) devices were fabricated with both I-/I-3(-) and [Cu(tmby)(2)](+/2+) electrolytes. DSSC devices sensitized with the AM1 and AM2 dyes showed relatively high-power conversion efficiency of 7.44 % and 7.22 %, respectively with I-/I-3(-) in the absence of chenodeoxycholic acid (CDCA) than those of the AM3 dye (5.41 %). The [Cu(tmby)(2)](+/2+) electrolyte along with poly(3,4-ethylenedioxythiophene) (PEDOT) as cathode material showed excellent open-circuit potentials (V-OC) of 1030, 1025, and 1001 mV with the DSSC efficiency of 8.05 %, 7.96 %, and 5.84 %, respectively, for the AM1, AM2, and AM3 dyes in the absence of CDCA. Here, the AM1 dye exhibited the maximum DSSC efficiency of 8.05 % and V-OC of 1030 mV, which is the highest obtained efficiency and V-OC for the visible-light active zwitterionic unsymmetrical-squaraine dye with copper-based electrolyte.

10aCu electrolytes10adihedral angle10aDye-sensitized solar cells10aopen circuit voltage10asquaraine dyes1 aSingh, Amrita1 aSingh, Ambarish, Kumar1 aDixit, Ruchi1 aVanka, Kumar1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/visible-light-active-unsymmetrical-squaraine-dyes-1-v-open-circuit-voltage-dye-sensitized02525nas a2200277 4500008004100000022001400041245012100055210006900176260000800245300001400253490000600267520153600273653002301809653003101832653002801863653002501891653001901916653001801935100002601953700003101979700002502010700002602035700003002061700002702091856012902118 2024 eng d a2574-096200aTriazatruxene amine donor-based visible-light-responsive unsymmetrical squaraine dyes for dye-sensitized solar cells0 aTriazatruxene amine donorbased visiblelightresponsive unsymmetri cSEP a7982-79910 v73 a

Optimized charge-transfer dynamics at the dye-TiO2/electrolyte interface are required for an enhanced dye-sensitized solar cell (DSSC) device performance. Such an optimized interface enhances the charge-injection, dye-regeneration, and diminished charge-recombination processes, synergistically enhancing the device efficiency. In this study, octupolar-structured sensitizers are designed to improve the interaction between the dye and the redox electrolyte for increasing the dye-regeneration process upon photoexcitation. Accordingly, a set of unsymmetrical squaraine dyes with indoline and triazatruxene amine donor-based D-A-D dyes are designed (KV1-KV3), synthesized, and sensitized with a semiconducting metal oxide (TiO2) film. The sensitizer forms a monolayer on the TiO2 surface, leading to a dye-dye interaction, which broadens the absorption spectrum. The N atom of the triazatruxene amine donor was left unsubstituted in KV1, whereas a hexyl chain was installed in KV2 and KV3 and a branched alkyl chain was installed on the core N atoms in KV3 to control the self-assembly of dyes on the TiO2 surface. Self-assembly of alkyl groups wrapped in KV1-KV3 dyes on the TiO2 surface aids surface passivation and broadens the absorption profile, improving the light-harvesting capabilities. The DSSC devices based on KV2 exhibited a high power conversion efficiency of 7.85% (V-oc = 794 mV, J(sc) = 14.76 mA/cm(2), and FF = 67%), with an onset incident photon-to-current conversion efficiency response from 680 nm.

10aaggregationof dyes10aDye-sensitized solar cells10ametal-free organic dyes10aself-assembly of dye10asquaraine dyes10atriazatruxene1 aIngole, Kiran, Balaso1 aDeshmukh, Shivdeep, Suresh1 aVerma, Tushar, Singh1 aKrishnamurty, Sailaja1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/triazatruxene-amine-donor-based-visible-light-responsive-unsymmetrical-squaraine-dyes-dye02640nas a2200289 4500008004100000022001400041245015900055210006900214260000800283300001100291490000800302520162200310653002401932653002101956653002401977653003102001653002502032653001902057653001802076100002602094700001602120700001702136700001702153700003002170700002702200856012302227 2025 eng d a1010-603000aDouble anchoring squaraine dye with triazatruxene amine donor for dye-sensitized solar cells: sequential cosensitization for panchromatic light-harvesting0 aDouble anchoring squaraine dye with triazatruxene amine donor fo cMAY a1162290 v4623 a

Dyes are firmly bound to a semiconducting TiO2 film using carboxylic acid anchoring groups for an efficient electron transfer from the excited state of dye to the conduction band (CB) of TiO2. Strong dye binding can be accomplished with multi-anchoring dye designs to improve photophysical characteristics, including high extinction coefficients, panchromatic absorption, post-sensitization modifications, and dark current suppression, besides enhancing the stability of the dye-TiO2 interface. Herein, a novel KV2D dye with double squaraine acceptor and double carboxylic acid anchoring groups is designed to achieve a high extinction coefficient (epsilon, 3.57 x 105M-1cm-1) and robust binding to the TiO2 film for an effective electron transfer. We systematically changed the amount of coadsorbent chenodeoxycholic acid (CDCA) to control the aggregation of dyes on the TiO2 surface that improves the power conversion efficiency (PCE, eta) for the devices based on the doubleanchoring KV2D. Out of these devices, KV2D: CDCA (1:10) based cell exhibited the best PCE of 5.26% with VOC of 754 mV, JSC of 10.41 mA/cm2, and ff of 67%. The sequential cosensitization studies were carried out with a far-red active dye to find the effect of the strong binding of the sensitizer to the TiO2 film. Interestingly, when di-anchoring, KV2D was sensitized first for 12 h and then sequentially cosensitized with far-red absorbing SQS4 for 5 h to achieve a PCE of 5.0% with VOC of 697 mV, JSC of 10.23 mA/cm2, and ff of 70% with panchromatic spectral response in IPCE upto 730 nm giving higher photocurrent generation.

10aaggregation of dyes10aBulky donor unit10aDouble acceptor dye10aDye-sensitized solar cells10aself-assembly of dye10asquaraine dyes10atriazatruxene1 aIngole, Kiran, Balaso1 aSiby, Jesna1 aPandya, Rinu1 aVanka, Kumar1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/double-anchoring-squaraine-dye-triazatruxene-amine-donor-dye-sensitized-solar-cells03071nas a2200277 4500008004100000022001400041245013500055210006900190260000900259300001400268490000600282520203300288653002402321653002502345653003102370653003502401653005202436100002402488700002702512700002702539700001602566700002602582700003002608700002702638856012802665 2025 eng d a2574-096200aEffect of cyclization and alkyl group wrapping in visible-light-active unsymmetrical squaraine dyes for dye-sensitized solar cells0 aEffect of cyclization and alkyl group wrapping in visiblelightac cAPR  a5017-50300 v83 a

A series of alkyl group-appended indoline- and carboxylic acid-functionalized indolenine-based visible-light-active unsymmetrical squaraine dyes, SQA7-10, were designed, synthesized, and utilized for the dye-sensitized solar cells device fabrication. The number of alkyl group has been increased systematically on the indoline moiety to control the self-assembly of dyes on TiO2 and to passivate the photoanode that helps in improving the open-circuit voltage (V-OC) by avoiding the charge recombination process. SQA7-10 dyes showed an absorption between lambda(max) 536-540 nm, with molar extinction coefficients of 1.62-2.13 x 10(5) M-1 cm(-1) in CH3CN. Further, ultraviolet-visible (UV-vis) studies on TiO2 indicated the formation of H-aggregated dyes (505-510 nm), which can be controlled by appending the alkyl groups. The energy levels of the highest occupied molecular orbital (HOMO) of these dyes are well aligned with the Nernst potentials of I-/I(3)(-)electrolyte and [Cu(tmby)(2)](+/2+) electrolytes with sufficient overpotentials required for the dye regeneration process. DSSC devices made with these dyes showed systematic enhancements of open-circuit voltage (V-OC) and device efficiency with respect to alkyl group incorporation for SQA7-10 with I-/I-3(-) electrolytes. All of the SQA dyes exhibited the device V-OC of more than 805 mV, where the introduction of alkyl groups systematically enhanced the V-OC in the order of SQA7 (805 mV) < SQA8 (829 mV) < SQA9 (843 mV) < SQA10 (862 mV) without any addition of CDCA. Within the SQA dye series, SQA10 dye has achieved the highest DSSC device efficiency of 7.52% (J(sc) of 11.16 mA/cm(2), V-oc of 862 mV, and ff of 78%) with I-/I-3(-) electrolyte, whereas use of [Cu(tmby)(2)](+/2+) redox shuttle with SQA10 showed enhanced V-oc (1080 mV) and device efficiency (8.35%). The IPCE profile for the device fabricated with SQA dyes showed good response at 480 and 560 nm, which indicates the photocurrent generation from the aggregated structures.

10aaggregation of dyes10acharge recombination10aDye-sensitized solar cells10aindoline and indolenine donors10avisible-light-activeunsymmetrical squaraine dye1 aJadhav, Avinash, P.1 aSingh, Ambarish, Kumar1 aShivankar, Bhavana, R.1 aSiby, Jesna1 aKrishnamurty, Sailaja1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/effect-cyclization-and-alkyl-group-wrapping-visible-light-active-unsymmetrical-squaraine03762nas a2200265 4500008004100000022001400041245015300055210007000208260000800278300001600286490000600302520279600308653002003104653002003124653003103144653003003175653002803205100002403233700001603257700001703273700001703290700003003307700002703337856013203364 2025 eng d a2574-096200aVisible-light active π-extended unsymmetrical squaraine dyes for dye-sensitized solar cells: steric effects for controlling the aggregation of dyes0 aVisiblelight active πextended unsymmetrical squaraine dyes for d cOCT a15459-154700 v83 a

The dye-anchored TiO2 photoanode plays a vital role in the light harvesting and charge separation processes in dye-sensitized solar cells. Aggregation of dyes (H- and J-type) on the TiO2 surface is a facile process due to the presence of a periodical dye anchoring sites on the exposed facet of titania, and such self-assembled dye structures help broadening the absorption profile. However, photocurrent generation from such aggregated structure is a challenging task in dye-sensitized solar cell devices. Hence, controlling the dye aggregation on the TiO2 surface is an important aspect. Controlling the aggregation of dyes by which (i) an enhanced photocurrent generation (J SC) and (ii) enhanced V OC can be achieved by including the steric factors to the dye design principles, the steric factor in the sensitizer may help passivate the TiO2 surface to avoid the charge recombination process between electrons present in TiO2 and the oxidized electrolyte. On the other hand, extension of pi-conjugation in a sensitizer helps enhance the light absorption in the visible region besides modulating the HOMO and LUMO energy levels. Hence, synergizing both pi-extensions along with features that control the dye aggregation has been considered in designing visible active squaraine dyes. A thiophene pi-spacer was inserted in between a visible-light active unsymmetrical squaraine unit and a cyanoacetic acid acceptor unit to provide the AJ1 and AJ2 dyes. Though both the dye molecules possess a similar pi-framework, the AJ2 dye was functionalized with both in-plane and out-of-plane alkyl groups to decrease the aggregation of dyes on the TiO2 surface compared to AJ1. The AJ1 and AJ2 dyes absorbed at 560 nm with shoulder peaks appeared at 528 nm, which can be assigned to vibronic progression (1082 cm-1), and additional characteristic peaks of thiophene appeared at 392 nm with the molar extinction coefficient of 1.16-1.19 x 105 M-1 cm-1 in CH3CN. The LUMO and HOMO energy levels are well aligned with the conduction band of TiO2 and the redox potential of iodolyte (I-/I3 -) electrolyte with sufficient overpotentials for charge injection and dye regeneration processes, respectively. The highest DSSC device efficiency of 7.37% (J SC 14.44 mA/cm2, V OC 0.771 V, ff 67.1%) was achieved for the AJ2 dye with iodolyte (I-/I3 -) electrolyte in the presence of 2 equiv of optically transparent coadsorbent chenodeoxycholic acid (CDCA), which showed a good IPCE response in between 400 and 700 nm. Further, cosensitization of visible-light active AJ1, AJ2, and SQA10 dyes with a complementary far-red active SQS4 dyes showed the device efficiencies of 5.53% (AJ1:SQS4:CDCA), 7.14% (AJ2:SQS4:CDCA), and 7.18% (SQA10:SQS4:CDCA) with a good IPCE response in the 400-720 nm region.

10acosensitization10aDye aggregation10aDye-sensitized solar cells10api-extended squaraine dye10avisible-lightactivedyes1 aJadhav, Avinash, P.1 aSiby, Jesna1 aPandya, Rinu1 aVanka, Kumar1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/visible-light-active-%CF%80-extended-unsymmetrical-squaraine-dyes-dye-sensitized-solar-cells02224nas a2200253 4500008004100000022001400041245018000055210006900235260000800304490000700312520127300319653002101592653003101613653002501644653001901669653001801688100002601706700001601732700001701748700001701765700003001782700002701812856013101839 2026 eng d a1861-472800aAuxiliary triazatruxene donor-based squaraine dyes for dye-sensitized solar cells: cis- and trans- configuration of dyes for modulating photophysical and electronic properties0 aAuxiliary triazatruxene donorbased squaraine dyes for dyesensiti cJAN0 v213 a

In DSSCs, dye regeneration efficiency and dye aggregation on the TiO2 surface can be modulated by using bulky aromatic donors wrapped with alkyl groups. Introduction of rigid aromatic rings around the donor unit of a dye will directly impact the driving force for electron injection and dye regeneration of a dye. In this work, we designed and synthesized KNS dyes with an auxiliary TAT donor integrated with a visible active squaraine dye. Here, octupolar-structured auxiliary TAT wrapped with alkyl groups is used as a strong donor and shelter to reduce the dye aggregation and charge recombination process. Further, to improve the light-harvesting efficiency and incident photon-to-current conversion efficiency of DSSC devices fabricated with KNS dyes, the central squaric acid unit has been modified by appending the electron-withdrawing dicyano group at the central squaric unit, and the trans-configured KNS1 dye was converted to cis-configured KNS2 dye. The power conversion efficiency of devices based on the KNS dyes was studied with and without 3 equivalents of CDCA by using the I-/I3 - electrolyte. Out of these devices, the KNS1: CDCA (1:3) based cell exhibited the best PCE of 6.25% with V OC of 793 mV, J SC of 11.08 mA cm-2, and ff of 71%.

10aBulky donor unit10aDye-sensitized solar cells10aself-assembly of dye10asquaraine dyes10atriazatruxene1 aIngole, Kiran, Balaso1 aSiby, Jesna1 aPandya, Rinu1 aVanka, Kumar1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/auxiliary-triazatruxene-donor-based-squaraine-dyes-dye-sensitized-solar-cells-cis-and-trans02133nas a2200229 4500008004100000022001400041245012400055210006900179260000900248300001100257490000800268520131200276653002501588653002001613653003101633653002301664653001901687653002401706100001601730700002701746856013001773 2026 eng d a1010-603000aD-A-D based NIR and visible homodimeric squaraine dyes for dye-sensitized solar cells: Modulation of excitonic coupling0 aDAD based NIR and visible homodimeric squaraine dyes for dyesens cAPR  a1168740 v4733 a

Dye-TiO2 interface plays a crucial role in the overall performance of dye-sensitized solar cells. Anchoring groups help to bind the dye on TiO2 and inject the electrons to the conduction band of TiO2. In this work, a series of homodimeric NIR squaraine dyes C6NIR, C10NIR, and visible squaraine dyes C6VIS, C10VIS are designed and synthesised. These dimeric dyes are covalently connected by decyl or hexyl units between the nonanchoring side of their monomeric unit. Optical spectroscopy in solution and on TiO2 surface indicates that the excitonic coupling between the dyes can be modulated. All the dimeric dyes showed better photovoltaic performance than their corresponding monomeric dyes. The dyes showed device performance SQ1 (1.28%) < C6NIR (2.26%) < C10NIR (2.79%) and AK2 (3.59%) < C6VIS (4.34%) < C10VIS (5.28%) respectively. The dimeric dyes showed better light harvesting efficiency and better passivation of the TiO2 surface. It helps to enhance the device's overall performance by improving the photocurrent and open circuit voltage. The decyl-linked dimeric dyes showed better performance among this set of dyes and C10NIR dyes showed V-oc of 614 mV, J(sc) of 7.08 mA/cm(2), and ff of 64.2%. and C10VIS showed V-oc of 724 mV, J(sc) of 10.74 mA/cm(2), and ff of 67.9%.

10acharge recombination10aDye aggregation10aDye-sensitized solar cells10aDye-TiO2 interface10asquaraine dyes10asurface passivation1 aSiby, Jesna1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/d-d-based-nir-and-visible-homodimeric-squaraine-dyes-dye-sensitized-solar-cells-modulation