The design and development of sensitizing dyes possessing wide-wavelength photon harvesting encompassing visible to near-infrared (NIR) wavelength regions are unavoidable for increasing the overall efficiency of dye-sensitized solar cells (DSSCs). In this study, three far-red-sensitive squaraine sensitizers were designed computationally, synthesized, and characterized, aiming towards their suitability as a potential sensitizer for DSSCs. It has been found that the incorporation of an electron acceptor moiety in the central squaraine core brought about a red shift in the absorption maximum (λ_max) and the emergence of a secondary absorption band in the blue region, thus broadening the photon-harvesting window. In addition, it also lowered the dye’s HOMO energy level enabling a facile regeneration of the photo-excited dye, which improved the photovoltaic performance of SQ-223, exhibiting a photoconversion efficiency (PCE) of 4.67%. Thereafter, to address the issue of wide-wavelength photon harvesting, DSSCs were fabricated by co-adsorbing two complementary dyes SQ-223 and D-131 in various molar ratios. The DSSC fabricated with D-131 and SQ-223 in 9:1 molar ratio displayed the best photovoltaic performance with a PCE of 5.81%, a significantly higher PCE when compared to corresponding individual dye-based DSSCs containing D-131 (3.94%) and SQ-223 (4.67%).

Two novel near‐infrared (NIR)‐sensitive unsymmetrical squaraine dyes, SQ‐258 and SQ‐259, for their suitability as a sensitizer in dye‐sensitized solar cells (DSSCs) are designed and synthesized, followed by photophysical and photovoltaic characterizations. It is demonstrated that introducing a 1,3‐indandione acceptor unit in the central squaric acid core of SQ‐259 leads to the suppression of dye aggregation owing to its nonplanar molecular geometry and the broadening of the optical absorption and photon‐harvesting window up to 800 nm. Owing to the extended wavelength photon harvesting, SQ‐259 improves the photoconversion efficiency (PCE) compared to its SQ‐258 dye counterpart. However, despite its wide wavelength photon harvesting, the improvement in the PCE of SQ‐259 is less pronounced, and this is attributed to the small driving force for injection of electrons (0.29 eV), hampered electronic coupling, and decreased electron lifetime for resistance to recombination (7.9 ms), which is confirmed by the cyclic voltammetry, quantum chemical calculation, and electrochemical impedance spectroscopic investigations, respectively.

The rapid evolution of organic field-effect transistors (OFETs) as versatile sensing platforms has primarily focused on architecture and probe engineering, often overlooking the intrinsic role of charge carrier mobility (μ) in transduction performance. Herein, we present a systematic study that correlates μ of polymer-based OFETs with critical sensing parameters using an extended-gate (EG) configuration for nonenzymatic glucose detection. To the best of our knowledge, this is the first EG-OFET study to quantitatively map how μ governs sensitivity, LOD/LOQ, and response time under an identical sensing architecture and measurement protocol. A novel nanocomposite, Ti₃C₂T_x/CuO, was synthesized as the active sensing interface and integrated with OFETs fabricated from conjugated polymers (CPs) with varying μ, such as NR-P3HT, RR-P3HT, and DPP-TTT. Uniaxially aligned, edge-on oriented, and uniform thin films of these CPs used as active semiconducting elements of the OFETs were fabricated by the unidirectional floating film transfer method. We demonstrate that increasing μ significantly enhances sensitivity, lowers detection limits, and improves response time. This is supported through a high-μ DPP-TTT-based, OFET achieving a remarkable sensitivity of 0.52 V mM^-1 cm^-2 and a detection limit of 0.56 mM, surpassing even standard electrochemical platforms. By codesigning a catalytic Ti₃C₂T_x/CuO extended-gate interface with mobility-engineered polymer transducers, we demonstrate a clear materials-transducer synergy in which higher μ enables stronger and faster electrical transduction of interfacial potential changes. These findings establish a μ-guided design rule for engineering next-generation EG-OFET sensors with improved sensitivity and speed. Thus, these findings bridge the gap between fundamental charge transport and applied sensing performance, establishing a new paradigm for engineering next-generation OFET sensors.