Developing effective and low‐cost organic hole‐transporting materials (HTMs) is crucial for the construction of high‐performance perovskite solar cells (PSCs) and to promote their production in commercial ventures. In this context, we herein report the molecular design, synthesis and characterization of two novel D‐A‐D‐A‐D architectured 9‐(2‐ethylhexyl)‐9H‐carbazoles, connecting the mono/dimethoxyphenyl substituted cyanovinylene sidearms symmetrically at 3rd and 6th positions of the carbazole heterocycle (CZ1‐2), as potential hole‐transporting materials (HTMs). The current work highlights their structural, photophysical, thermal, electrochemical and theoretical investigations, including their structure‐property correlation studies. Evidently, the optical studies showcased their excellent fluorescence ability due to their push–pull natured structure with extended π‐conjugation. Further, in‐depth solvatochromic studies demonstrated their intramolecular charge‐transfer (ICT)‐dominated optoelectronic behavior, supported by various correlation studies. Also, the optical results revealed that CZ1 and CZ2 display λabs and λemi in the order of 410–430 nm and 530–560 nm, respectively, with a bandgap in the range of 2.5–2.6 eV. Finally, their quantum chemical simulations have provided an insight into the predictions of their structural, molecular, electronic and optical parameters. Conclusively, the study furnishes a deeper understanding of the intricacies involved in the structural modification of carbazole‐based HTMs for achieving better performance.

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We present the fabrication of highly efficient large-area carbonbased perovskite solar cells (C-PSCs) using CsX (X = Cl, Br, and I)-modified mesoporous (mp) TiO 2 beads of 40 nm size as an electron transport material. Here, triple-layered scaffolds made of cesium halide-modified TiO 2 exhibit efficient charge extraction as confirmed by enhanced photoluminescence quenching and inhibit the UV-activated degradation processes of perovskite, leading to an enhanced operational stability. Among the three cesium halide modifications, devices containing CsBr-modified TiO 2 showed the highest short-circuit current density, yielding a photoconversion efficiency (PCE) of 12.59% of the device, with 0.7 cm 2 active area and 11.55% for a large-area module (70 cm 2 ). These devices are stable in an ambient atmosphere (25 °C, 65−70% RH) over 2700 h as well as at a high temperature (85 °C) over 750 h with virtually no hysteresis.

Herein, we report the design and synthesis of four new thiophene-bridged D-π-A configured organic dyes T1-4 comprising different donors, π-spacers and anchoring units, as potential sensitizers, and co-sensitizers for DSSCs....

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