02581nas 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-solar02005nas 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-dye02030nas 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-cobalt