A rare combination of dual static and dynamic fluorescence quenching mechanisms is reported, while sensing the nitroexplosive trinitrotoluene (TNT) in water by a cationic conjugated copolymer PFPy. Since the fluorophore PFPy interacts with TNT in both ground state as well as the excited states, a greater extent of interaction is facilitated between PFPy and the TNT, as a result of which the magnitude of the signal is amplified remarkably. The existence of these collective sensing mechanisms provides additional advantages to the sensing process and enhances the sensing parameters, such as LoD and highly competitive sensing processes in natural water bodies irrespective of the pH and at ambient conditions. These outcomes involving dual sensing mechanistic pathways expand the scope of developing efficient sensing probes for toxic chemical analyte and biomarker detection, preventing environmental pollution and strengthening security at sensitive locations while assisting in early diagnosis of disease biomarkers.

Chemical passivation of ionic defects in perovskite materials is an effective strategy to reduce charge recombination in perovskite solar cells (PSCs). Although several additives have been used for this purpose, the passivation mechanisms of different functional groups have remained unclear. Herein, the effect of molecules possessing multiple functional anchoring is systematically investigated. Three different multifunctional molecules namely 5‐aminoisophthalic acid (AIA), 5‐hydroxyisophthalic acid (HIA), and chelidamic acid (CA) are strategically chosen. These molecules not only take part in the crystallization process but also passivate the trap states effectively. CA shows superior passivation capacity among all with a better dipolar electron density distribution. The passivated films have considerably improved morphology with fewer pin holes, larger grains, and lower trap states in comparison to the pristine film. CA‐passivated p–i–n structured photovoltaic devices demonstrate the best power conversion efficiency (PCE) of 19.06% with an impressive open circuit voltage (VOC) of 1.097 V, whereas pristine devices show a PCE of 13.60% and VOC of 0.972 V. Moreover, the modified device reveals notable thermal and ambient stability in comparison to the pristine device due to lower defect states and reduced ion migration.

Recently, organic-inorganic hybrid perovskite solar cells (PSCs) have experienced a rapid growth in terms of efficiency. However, the instability of hybrid perovskite materials towards ambient conditions restricts its commercialization. Formation...

Developing large-scale perovskite solar cells requires highquality defect-free perovskite films with improved surface coverage. One of the most convenient ways to achieve this is through the incorporation of appropriate passivation molecules in the perovskite films. Herein, the effect of a novel conjugated polyelectrolyte, PHIA, is investigated for perovskite passivation by the comprehensive analysis of perovskite films and devices. The PHIA polymer significantly diminishes the trap states in perovskite films, and the passivated device permits lesser recombination, very low accumulation of charges at the interface, and lowers the traps which facilitated superior charge transport. As a result, a high power conversion efficiency of 20.17% has been achieved for the PHIA-modified device. Additionally, this passivation approach effectively enhanced the long-term device stability by improving the hydrophobicity of the perovskite layer. Furthermore, a large-area device (2 cm 2 ) has also been fabricated to demonstrate the expediency of this approach for future commercialization.

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Trap state formation in perovskite films during their preparation is a key limitation restricting the device performance and stability of perovskite solar cells. These trap states are generally present at the surface of perovskite films and on grain boundaries and work as charge recombination centers, thereby influencing the device performance. Hence, regulating these detrimental trap states that are susceptible to deformation is vital for improving the solar cell performance. Herein, a unique methodology of trap states passivation has been demonstrated using multiple carboxylic acid-functionalized small aromatic molecules. Three additives, viz., benzene carboxylic acid (BCA), benzene-1,3-dicarboxylic acid (BDCA), and benzene-1,3,5-tricarboxylic acid (BTCA), have been utilized as additives in the precursor solution that reduced trap states in the perovskite films. Perovskite films generated in the presence of these additives strongly influence the charge transfer dynamics and result in improved performance and stability of the devices by lowering the photogenerated charge recombination. BTCA-incorporated devices result in the highest power conversion efficiency (PCE) of 18.30% with a significant improvement in the open-circuit voltage (V oc) to 1075.9 mV (an enhancement of ≈80 mV) compared to the control device. Additionally, the devices also show enhanced thermal stability.

The selection of dielectric material impacts the dielectric/semiconductor (D/S) interface which plays a significant role in defining the device performance. Hence, investigation of the D/S interfacial defects and trap states is essential for improving the device performance and designing new semiconductor and dielectric materials for organic field effect transistors (OFET). Here, the trap density of states (DOS) at the interface is investigated by impedance spectroscopy (IS). OFETs are fabricated with three different dielectric combinations and the highest mobility is found to be 0.12 cm2 V−1 s−1. Detailed analysis of the semiconductor thin film and the D/S interface is performed by atomic force microscopy, photoluminescence, time‐resolved photoluminescence and is found consistent with the DOS analysis. This work validates that IS can be utilized as a prospective DOS analysis method for OFET applications. Finally, for evaluating the potential application of the device architecture toward developing flexible electronic circuit components, the device is fabricated on a flexible substrate and the mechanical stability is examined by subjecting the device to a strain of 2.5%. The device shows no significant degradation in operation, confirming its practical utility.

Fabrication of high performance polymer solar cells through the hot-casting technique, which modulates the thickness and roughness of the active layer and also the carrier mobility of the solar cell devices.