Zr-based UiO-66 metal–organic framework (MOF) is one of the most studied MOFs with a wide range of potential applications. While UiO-66 is typically synthesized as a microcrystalline solid, we employ a particle downsizing strategy to synthesize UiO-66 as fluid gel with unique rheological properties, which allows the solution-based processing as sub-100 nm films and enhances the electrical conductivity of its pristine structure. Film thicknesses ranging from 40 to 150 nm could be achieved by controlling the spin-coating parameters. The generality of the method is also demonstrated for other Zr-based MOFs including MOF-801 and MOF-808. The impact of particle size and film thickness at the nanoscale on electrical properties of UiO-66 is shown to realize new features that are distinct from those of the bulk powder phase. An electrical insulator UiO-66 shows a significant increase in the electrical conductivity (10–5 S cm–1 compared to 10–7 S cm–1 in the bulk powder phase) when the 10 nm particles are distributed on the substrate with a thickness less than 100 nm. The findings establish a new route for processing of MOF materials as thin films with fine-tuned thickness and offer a new perspective for transport properties of Zr-based MOFs without structural modification.

Solution‐processed copper(I) thiocyanate (CuSCN) typically exhibits low crystallinity with short‐range order; the defects result in a high density of trap states that limit the device's performance. Despite the extensive electronic applications of CuSCN, its defect properties are not understood in detail. Through X‐ray absorption spectroscopy, pristine CuSCN prepared from the standard diethyl sulfide‐based recipe is found to contain under‐coordinated Cu atoms, pointing to the presence of SCN− vacancies. A defect passivation strategy is introduced by adding solid I2 to the processing solution. At small concentrations, the iodine is found to exist as I− which can substitute for the missing SCN− ligand, effectively healing the defective sites and restoring the coordination around Cu. Computational study results also verify this point. Applying I2‐doped CuSCN as a p‐channel in thin‐film transistors shows that the hole mobility increases by more than five times at the optimal doping concentration of 0.5 mol.%. Importantly, the on/off current ratio and the subthreshold characteristics also improve as the I2 doping method leads to the defect‐healing effect while avoiding the creation of detrimental impurity states. An analysis of the capacitance‐voltage characteristics corroborates that the trap state density is reduced upon I2 addition.

Undoped and Nb-doped TiO 2 nanocrystals are prepared by a microwave-assisted non-aqueous sol–gel method based on a slow alkyl chloride elimination reaction between metal chlorides and benzyl alcohol. Sub-4 nm nanoparticles are grown under microwave irradiation at 80 °C in only 3 h with precise control of growth parameters and yield. The obtained nanocrystals could be conveniently used to cast compact TiO 2 or Nb-doped TiO 2 electron transport layers for application in formamidinium lead iodide-based photovoltaic devices. Niobium doping is found to improve the cell performance by increasing the conductivity and mobility of the electron transport layer. At the same time, a measurable decrease in parasitic light absorption in the low wavelength portion of the spectrum was observed.

The solid-state mechanochemical reactions under ambient conditions of CuSCN and Zn(SCN) 2 resulted in two novel materials: partially Zn-substituted α-CuSCN and a new phase Cu x Zn y (SCN) x+2y . The reactions take place at the labile Sterminal, and both products show melting and glass transition behaviors. The optical band gap and solid-state ionization potential can be adjusted systematically by adjusting the Cu/Zn ratio. Density functional theory calculations also reveal that the Znsubstituted CuSCN structure features a complementary electronic structure of Cu 3d states at the valence band maximum and Zn 4s states at the conduction band minimum. This work shows a new route to develop semiconductors based on coordination polymers, which are becoming technologically relevant for electronic and optoelectronic applications.

<p>The solid-state mechanochemical reactions under ambient conditions of CuSCN and Zn(SCN)₂ resulted in two novel materials: partially Zn-substituted <i>α</i>-CuSCN and a new phase Cu_xZn_y(SCN)_x+2y. The reactions take place at the labile S-terminal, and both products show melting and glass transition behaviors. The optical band gap and solid-state ionization potential can be adjusted systematically by adjusting the Cu:Zn ratio. Density functional theory calculations also reveal that the Zn-substituted CuSCN structure features a complementary electronic structure of Cu 3<i>d</i> states at the valence band maximum (VBM) and Zn 4<i>s</i> states at the conduction band minimum (CBM). This work shows a new route to develop semiconductors based on coordination polymers which are becoming technologically relevant for electronic and optoelectronic applications.</p>