A facile hydrothermal method to synthesize water-soluble copper indium sulfide (CIS) nanocrystals (NCs) at 150 °C is presented. The obtained samples exhibited three distinct photoluminescence peaks in the red, green and blue spectral regions, corresponding to three size fractions, which could be separated by means of size-selective precipitation. While the red and green emitting fractions consist of 4.5 and 2.5 nm CIS NCs, the blue fraction was identified as in situ formed carbon nanodots showing excitation wavelength dependent emission. When used as light absorbers in quantum dot sensitized solar cells, the individual green and red fractions yielded power conversion efficiencies of 2.9% and 2.6%, respectively. With the unfractionated samples, the efficiency values approaching 5% were obtained. This improvement was mainly due to a significantly enhanced photocurrent arising from complementary panchromatic absorption.

Quantum dot‐sensitized solar cells (QDSSCs) are promising for sustainable energy generation but face efficiency and cost barriers. In this configuration, counter electrodes (CEs) play a crucial role in overcoming these barriers. In this study, the novel CEs are investigated based on nanocomposites of polyaniline (PANI/Cu _x S) and polyaniline‐multi‐walled carbon nanotubes/copper sulfide (PANI‐MWCNT/Cu _x S) electrodeposited on a fluorine‐doped tin oxide (FTO) substrate to overcome these challenges. The CEs are characterized by Infrared and Raman spectroscopy, X‐ray diffraction, scanning electron microscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy. These nanocomposites based on polyaniline (PANI) are applied as CE in cadmium sulfide (CdS) QDSSCs, which presented energy conversion efficiencies of 1.99% and 2.39%, respectively, under standard irradiation, representing an increase of more than 50% compared to the Cu _x S CE. These PANI‐based CEs presented lower charge‐transfer resistance (32 Ω) and better photovoltaic performance than conventionally used Cu and Cu _x S CEs, and they are promising for application in QDSSCs because they have been prepared with materials that are widely used in electronic devices and can be an option for large‐scale production.

In this work we investigated the thermal conductivity of tetrabenzo[8]circulene (TB8C) through the Equilibrium Molecular Dynamics (EMD) simulations. Through this investigation we propose an estimated value for the thermal conductivity of TB8C not yet reported in the literature. The TB8C thermal conductivity was simulated for different temperatures. We compared the average thermal conductivity value, (216 ± 2) W m⁻¹ K⁻¹ with the simulated thermal conductivity of graphene, carbon nanotube and C₈₀H₃₀ molecule, reported in the literature. This comparison suggests that the size and structure containing defects of TB8C, in relation to the intrinsic graphene plane hexagonal structure model, are responsible for its good thermal conductivity. To clarify the mechanism of the thermal behaviour of TB8C, we calculated the Phonon Density of States (PHDOS) and compared with C₈₀H₃₀ and graphene. When compared to graphene, a higher phonon density of state is observed for the TB8C in the frequency range from 0 to 10 THz, which may be an explanation for the high thermal conductivity of the TB8C. By calculating the group velocity, we proposed the hypothesis that the lifetime of phonons, for TB8C, should be greater than that of graphene and proposed that thermal transport should occur, predominantly, in ballistic form.