@article {49137, title = {Modular TiO2-squaraine dyes/electrolyte interface for dye-sensitized solar cells with cobalt electrolyte}, journal = {Chemphotochem}, volume = {7}, year = {2023}, month = {APR}, type = {Article}, abstract = {

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.

}, keywords = {counter-electrode, DSSC device efficiency, Dye-sensitized solar cells, Electrolytes, unsymmetrical squaraine dye}, issn = {2367-0932}, doi = {10.1002/cptc.202200171}, author = {Singh, Ambarish Kumar and Sudhakar, Vediappan and Javaregowda, Bharathkumar H. and Bisht, Rajesh and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} } @article {48746, title = {Visible-light-active unsymmetrical squaraine dyes with 1 V of open-circuit voltage for dye-sensitized solar cells}, journal = {ChemPhotoChem}, volume = {7}, year = {2023}, month = {MAY}, type = {Article}, abstract = {

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.

}, keywords = {Cu electrolytes, dihedral angle, Dye-sensitized solar cells, open circuit voltage, squaraine dyes}, issn = {2367-0932}, doi = {10.1002/cptc.202200328}, author = {Singh, Amrita and Kumar Singh, Ambarish and Dixit, Ruchi and Vanka, Kumar and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} } @article {49283, title = {Triazatruxene amine donor-based visible-light-responsive unsymmetrical squaraine dyes for dye-sensitized solar cells}, journal = {ACS Applied Energy Materials}, volume = {7}, year = {2024}, month = {SEP}, pages = {7982-7991}, type = {Article}, abstract = {

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.

}, keywords = {aggregationof dyes, Dye-sensitized solar cells, metal-free organic dyes, self-assembly of dye, squaraine dyes, triazatruxene}, issn = {2574-0962}, doi = {10.1021/acsaem.4c01591}, author = {Ingole, Kiran Balaso and Deshmukh, Shivdeep Suresh and Verma, Tushar Singh and Krishnamurty, Sailaja and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} }