Fluorophores functionalized with heavy elements show enhanced intersystem crossing due to increased spin–orbit coupling, which in turn shortens the fluorescence decay lifetime (τ^PL). This phenomenon is known as the heavy-atom effect (HAE). Here, we report the observation of increased τ^PL upon functionalisation of near-infrared photoluminescent gold nanoclusters with iodine. The heavy atom-mediated increase in τ^PL is in striking contrast with the HAE and referred to as inverse HAE. Femtosecond and nanosecond transient absorption spectroscopy revealed overcompensation of a slight decrease in lifetime of the transition associated with the Au core (ps) by a large increase in the long-lived triplet state lifetime associated with the Au shell, which contributed to the observed inverse HAE. This unique observation of inverse HAE in gold nanoclusters provides the means to enhance the triplet excited state lifetime.

The synthesis of poly[N-(3-(9H-carbazol-9-yl)propyl)methacrylamide] (PCaPMA) is presented, along with its physical, photophysical, and electrical properties, revealing its promising potential for the application in bistable memory devices. The incorporation of the carbazole heterocycle, as a functional charge carrier transporting unit attached to a saturated polymethacryalamide backbone by a flexible alkyl chain, facilitates resistive switching by the applied voltage. Thin films of the polymer, sandwiched between Al or Au and ITO electrodes, exhibit rewriteable flash memory behavior with bistable conductivity with a setting voltage ranging from 2 to 4.5 V, achieving a current ON/OFF ratio exceeding 100. The device demonstrates a remarkable lifetime and remains persistent for more than 10⁴ seconds under a static voltage of 0.5 V. The main physical mechanisms driving the resistive switching have been attributed to the electric field-induced reorientation of heterocycles, which modulates charge transport, and trapping/detrapping of charges in localized states within the bulk of the polymer. Memory persistence is strengthened by the physical crosslinking caused by hydrogen bonds between amide and carbonyl groups in the aliphatic side chains. This physical network further enhances the thermal and mechanical stability of the PCaPMA in comparison to similar polymers highlighting its potential as a suitable material for organic memory devices.

Poly(p-phenylenediamine)/montmorillonite (PPDA/MMT) composites were prepared by the oxidative polymerization of monomers intercalated within the MMT gallery, using ammonium peroxydisulfate as an oxidant. The intercalation process was evidenced by X-ray powder diffraction. The FT-IR and Raman spectroscopies revealed that, depending on the initial ratio between monomers and MMT in the polymerization mixture, the polymer or mainly oligomers are created during polymerization. The DC conductivity of composites was found to be higher than the conductivity of pristine polymer, reaching the highest value of 10⁻⁶ S cm⁻¹ for the optimal MMT amount used during polymerization. Impedance spectroscopy was performed over wide frequency and temperature ranges to study the charge transport mechanism. The data analyzed in the framework of conductivity formalism suggest different conduction mechanisms for high and low temperature regions.

Ultrathin electrospun nanofibrous membranes (NfMs) based on poly(γ-benzyl-L-glutamate) (PBLG) were prepared. Scanning electron microscopy analysis revealed the production of a high-quality, bead-free nanofibrous membrane. The membrane thicknesses, ranging from 1.7 to 4.5 μm, were found to correlate directly with membrane porosity. Raman scattering analysis was utilized to investigate the conformation of the PBLG nanofibrous membrane and to assess the effects of addition of 1 wt. % trifluoroacetic acid (TFA) into the PBLG solutions, as well as the impact of annealing at 70 °C. In addition, x-ray photoelectron spectroscopy (XPS) characterization was performed to elucidate the chemical composition of the PBLG nanofibrous membrane. The Raman and Fourier-transform infrared spectroscopy spectra indicated the characteristic α-helical conformation in both the PBLG solution and the PBLG nanofibrous membrane. Furthermore, a comparative analysis of Raman band profiles proved the absence of TFA after annealing, supporting the hypothesis of TFA evaporation post-annealing, which was subsequently confirmed by the XPS results. In addition, the results from the small punch test revealed a significant correlation between membrane thickness and stiffness, indicating that increased thickness enhances stiffness. This comprehensive study provides valuable insights into the structural and compositional properties of PBLG NfMs, laying the groundwork for future investigations into their potential applications in the field of tissue engineering.

Diketopyrrolopyrrole (DPP) functionalised with an electron donating unit acts as a donor‐acceptor molecules that have shown potential for application in dyes and photovoltaics. These molecules offer broad absorption/emission properties and structure‐dependent dynamics. In this study, we used femtosecond pump‐probe spectroscopy to investigate the photo‐initiated dynamics of thiophene linked DPP derivatives. The thio‐DPPs are further functionalised by different electrons withdrawing terminal groups, namely benzoxazole and thiophene dicyanide. The benzoxazole derivative is strongly emissive and directly relaxes directly to the ground state chloroform solution. Thiophene dicyanide derivative exhibits distinct spectral evolution in the first 10 ps, associated with structural and vibronic process. Later, it crosses over to the triplet state with a yield of 20 %. In the solid‐state (thin film), we observed a signal that resembles singlet fission. However, upon careful analysis of temperature‐dependent steady state absorbance spectra, we conclude that these features are due to laser‐induced thermal artifacts. We describe a simplified excited state evolution in the thin film that does not include any additional excited states. These findings have significant implications for the analysis of triplet formation, which plays a major role in the photophysics of many organic materials.