@article {49614, title = {Double anchoring squaraine dye with triazatruxene amine donor for dye-sensitized solar cells: sequential cosensitization for panchromatic light-harvesting}, journal = {Journal of Photochemistry and Photobiology A-Chemistry}, volume = {462}, year = {2025}, month = {MAY}, pages = {116229}, type = {Article}, abstract = {

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.

}, keywords = {aggregation of dyes, Bulky donor unit, Double acceptor dye, Dye-sensitized solar cells, self-assembly of dye, squaraine dyes, triazatruxene}, issn = {1010-6030}, doi = {10.1016/j.jphotochem.2024.116229}, author = {Ingole, Kiran Balaso and Siby, Jesna and Pandya, Rinu and Vanka, Kumar and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} } @article {49788, title = {Auxiliary triazatruxene donor-based squaraine dyes for dye-sensitized solar cells: cis- and trans- configuration of dyes for modulating photophysical and electronic properties}, journal = {Chemistry-an Asian Journal}, volume = {21}, year = {2026}, month = {JAN}, type = {Article}, abstract = {

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\%.

}, keywords = {Bulky donor unit, Dye-sensitized solar cells, self-assembly of dye, squaraine dyes, triazatruxene}, issn = {1861-4728}, doi = {10.1002/asia.70455}, author = {Ingole, Kiran Balaso and Siby, Jesna and Pandya, Rinu and Vanka, Kumar and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} } @article {49843, title = {D-A-D based NIR and visible homodimeric squaraine dyes for dye-sensitized solar cells: Modulation of excitonic coupling}, journal = {Journal of Photochemistry and Photobiology A-Chemistry}, volume = {473}, year = {2026}, month = {APR }, pages = {116874}, type = {Article}, abstract = {

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{\textquoteright}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\%.

}, keywords = {charge recombination, Dye aggregation, Dye-sensitized solar cells, Dye-TiO2 interface, squaraine dyes, surface passivation}, issn = {1010-6030}, doi = {10.1016/j.jphotochem.2025.116874}, author = {Siby, Jesna and Nithyanandhan, Jayaraj} }