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It is highly desirable to secure the net-zero targets by employing sustainable building materials that can store and release their energy depending on the weather.

TiVO4 photoanode was prepared using the spray pyrolysis technique and further employed for photoelectrochemical water splitting to produce hydrogen.

Organo-metal halide perovskite field-effect transistors present serious challenges in terms of device stability and hysteresis in the current-voltage characteristics. Migration of ions located at grain boundaries and surface defects in the perovskite film are the main reasons for instability and hysteresis issues. Here, we introduce a perovskite grain molecular cross-linking approach combined with amine-based surface passivation to address these issues. Molecular cross-linking was achieved through hydrogen bond interactions between perovskite halogens and dangling bonds present at grain boundaries and a hydrophobic cross-linker, namely diethyl-(12-phosphonododecyl)phosphonate, added to the precursor solution. With our approach, we obtained smooth and compact perovskite layers composed of tightly bound grains hence significantly suppressing the generation and migration of ions. Moreover, we achieved efficient surface passivation of the perovskite films upon surface treatment with an amine-bearing polymer, namely polyethylenimine ethoxylated. With our synergistic grain and surface passivation approach, we were able to demonstrate the first perovskite transistor with a complete lack of hysteresis and unprecedented stability upon continuous operation under ambient conditions. Added to the merits are its ambipolar transport of opposite carriers with balanced hole and electron mobilities of 4.02 and 3.35 cm(2) V-1 s(-1), respectively, its high I-on/I-off ratio >10(4) and the lowest sub-threshold swing of 267 mV dec(-1) reported to date for any perovskite transistor. These remarkable achievements obtained through a cost-effective molecular cross-linking of grains combined with amine-based surface passivation of the perovskite films open a new era and pave the way for the practical application of perovskite transistors in low-cost electronic circuits.

A polymer gel electrolyte (PGE), using poly(styrene-co-acrylonitrile) (SAN) as a gelator, 1-butyl-3-methylimidazolium iodide (BMIMI) as the ionic liquid, and lithium iodide (LiI) as a source of iodide ions, is synthesized and investigated for its performance while employing it in a quasi-solid-state dye-sensitized solar cell using a N719 sensitizer and an I−/I3− redox couple. The PGEs are synthesized using different wt% of SAN and the relative amounts of LiI and I2 are optimized for iodide ion (I−) and triiodide ion (I3−) generation and their influence on the photovoltaic performance of the devices was investigated. On optimizing the PGE composition, the device gives an ionic conductivity of 7.00 mS cm−1, with a triiodide diffusion coefficient of 7.28 × 10−5 cm2 s−1, ensuring efficient polymer networks for the mobility of ionic species. The absorption edge for all PGEs lies close to ∼420 nm having transparency of more than 80% in the visible and NIR region. Impedance analysis evidently supports 17 wt% SAN as the optimum composition for PGE with better charge transfer and a decrease in recombination rate and considerable improvement in the electron lifetime. The highest photovoltaic conversion efficiency is 6.72% with the 17 wt% SAN PGE.

Size-tunability of the electronic and optical properties of semiconductor quantum dots and nanoclusters is due to the quantum size effect, which causes variations in the electronic excitations as the particle boundaries are changed. Recently, CdSe and CdTe quantum dots have been used in energy harvesting devices. Despite these promising practical applications, a complete understanding of the electronic transitions associated with the surfaces of the nanoparticles is currently lacking and is difficult to achieve experimentally. Computational methods could provide valuable insights and allow us to understand the electronic and optical properties of quantum dots and nanoclusters. Hollow cage and endohedral or core–shell cage structures for CdnTen clusters have been reported before. We have performed systematic density functional theory (DFT) studies on the structure and electronic properties of the CdnTen (n = 1–17) clusters. As the number of atoms increases in the CdnTen clusters, the predicted geometries change from simple planar structures to more complicated 3D-structures. Two classes of the most stable structures were elucidated for clusters with n = 10–17: (i) hollow cage structures with an empty center; and (ii) endohedral or core–shell cage structures with one or more atoms inside the cage. Noticeably higher highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps were observed for the hollow cage isomers as compared to the core–shell structures. The highest occupied molecular orbitals of all of the clusters studied were shown to be localized on the surface of the cage for the hollow cage structures, while in the case of the core–shell structures, the HOMO electron densities were found to be distributed both on surface and the interior of the structures. Most of the small size clusters CdnTen (n = 2–9) showed minimal values for the dipole moments (close to zero) owing to the highly ordered and symmetric configurations of these structures. For isomers of the larger clusters (n = 10–17), it was observed that the core–shell structures have higher values for the dipole moments than the hollow cage species because of the highly symmetric structures of the hollow cages. Core–shell cage structures exhibited lower polarizability than the respective hollow cage structures.

Heterobimetallic molecular Cu–Ni and Cu–Co complexes [Cu2Ni4(acac)2(dmae)2(dmaeH)2(OH)(TFA)6] (1) and [Cu2Co4(acac)2(dmae)2(dmaeH)2(OH)(TFA)6] (2) [dmae = N,N-dimethylaminoethanol, TFA = trifluoroacetic acid and acac = 2,4-pentanedionate] were prepared and tested as precursors for the deposition of mixed metal oxide composite thin films. The complexes were synthesized by reaction of the tetrameric copper(II) complex [Cu(dmae)(TFA)]4 with M(acac)2·xH2O [M = Ni, x = 2; Co, x = 1] in THF and were characterized by melting point, elemental analysis, FT-IR spectroscopy, TG/DTG and single-crystal X-ray diffraction. The complexes are isomorphous and crystallize in the triclinic centrosymmetric space group P. Aerosol assisted chemical vapour deposition (AACVD) studies carried out on (1) and (2) showed that they are promising precursors for the deposition of thin films of crystalline CuO–NiO and Cu2O–CoO composites, respectively. The size, shape, surface morphology, microstructure, chemical composition and crystallinity of the resulting mixed-metal oxide composite thin films were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis proved that the thin films are crystalline, uniform, smooth and tightly adherent to the substrates.

Heterobimetallic molecular precursors [Ba(dmap)4Cu4(OAc)6·THF] (1) and [Ba(dmap)4Cu4(TFA)6·THF] (2) [dmap = N,N-dimethylaminopropanolate, OAc = acetate and TFA = trifluoroacetate] for the deposition of barium–copper composite oxide thin films, were prepared by the interaction of Ba(dmap)2 with Cu(OAc)2 for 1 and Cu(TFA)2 for 2, in THF. Both heterobimetallic complexes were characterized by melting point, elemental analysis, FT-IR spectroscopy, mass spectrometry and single crystal X-ray diffraction. X-Ray crystallography shows that complex 1 crystallizes in the orthorhombic space groupP212121 with the cell dimensions a = 11.2621(11) A, b = 18.2768(17) A and c = 24.541(2) A, while complex 2 crystallizes in the monoclinic space groupC2/c with a = 23.9288(14) A, b = 19.8564(12) A, c = 25.5925(15) A and β = 112.4390(10)°. Thermal gravimetric analysis shows that both complexes 1 and 2 undergo controlled thermal decomposition at 450 °C and 400 °C, respectively, to give mixed metal oxide composite thin films. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray powder diffraction (XRD) analyses of the thin films suggest the formation of good quality crystalline thin films of BaCuO2–CuO composites from both 1 and 2, with average grain sizes of 105 to 175 nm and 110 to 205 nm, respectively.