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An in situ microsynthesis of polyaniline films directly on a substrate was developed and considered from the viewpoint of conductivity as a key functional property. The microsynthesis was carried out in a reaction volume of 60 μL. The multi-analytical study of polyaniline samples obtained by in situ microsynthesis was performed. The effect of synthesis parameters (reaction time, temperature, and number of synthetic procedures on the same substrate) on the structure, morphology and conductivity was investigated. It was shown that the in situ microsynthesis allows for the formation of polyaniline films in the whole range of synthesis parameters chosen. The correlations between synthetic conditions, structural parameters and conductivity are discussed. The found correlations between FTIR parameters and conductivity can be considered as a promising tool for PANI characterization. [ABSTRACT FROM AUTHOR]

We present a procedure to grow thin films of lead sulfide (PbS) with 'solution Atomic Layer Deposition' (sALD), a technique which transfers the principles of ALD from the gas phase (gALD) to liquid processing. PbS thin films are successfully deposited on planar and porous substrates with a procedure that exhibits the unique ALD characteristics of self-limiting surface chemistry and linear growth at room temperature. The polycrystalline p-type PbS films are stoichiometric and pure. They are converted to the hybrid perovskite methylammonium iodoplumbate (methylammonium lead iodide, MAPI, CH3NH3PbI3) by annealing to 150 °C in the presence of vapors from methylammonium iodide (MAI). [ABSTRACT FROM AUTHOR]

Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO 2 /Sb 2 S 3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over the ZnS interlayer thickness on the ångström scale (0-1.5 nm) and to deposit highly pure Sb 2 S 3 . Our systematic study of the photovoltaic and optoelectronic properties of these devices by impedance spectroscopy and transient absorption concludes that the optimum ZnS interlayer thickness of 1.0 nm achieves the best balance between the beneficial effect of an increased recombination resistance at the interface and the deleterious barrier behavior of the wide-bandgap semiconductor ZnS. This optimization allows us to reach an overall power conversion efficiency of 5.09% in planar configuration.

TiO 2 nanotubes generated by anodization of metallic titanium sputter-coated on indium tin oxide (ITO) substrates are used as a conductive scaffold for all solid-state Sb 2 S 3 -sensitized extremely thin absorber (ETA) solar cells. A blocking layer of TiO 2 placed between Ti and ITO in combination with optimized Ti deposition and anodization conditions enables the formation of crack-free layers of straight, cylindrical TiO 2 nanotubes of tunable length and diameter. ALD (atomic layer deposition) is subsequently used to coat this substrate conformally with a highly pure Sb 2 S 3 light absorber layer under an inert atmosphere. The high absorption coefficient of Sb 2 S 3 as compared to molecular dyes allows for the utilization of very short nanotubes, which facilitates the infiltration of the organic hole transport material and formation of a p-i-n heterojunction in an interdigitated and tunable geometry. We investigate the influence of nanotube length and of the absorber thickness to enhance the photocurrent value to twice that of planar reference structures., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

The combination of oxide and heavier chalcogenide layers in thin film photovoltaics suffers limitations associated with oxygen incorporation and sulfur deficiency in the chalcogenide layer or with a chemical incompatibility which results in dewetting issues and defect states at the interface. Here, we establish atomic layer deposition (ALD) as a tool to overcome these limitations. ALD allows one to obtain highly pure Sb 2 S 3 light absorber layers, and we exploit this technique to generate an additional interfacial layer consisting of 1.5 nm ZnS. This ultrathin layer simultaneously resolves dewetting and passivates defect states at the interface. We demonstrate via transient absorption spectroscopy that interfacial electron recombination is one order of magnitude slower at the ZnS-engineered interface than hole recombination at the Sb 2 S 3 /P3HT interface. The comparison of solar cells with and without oxide incorporation in Sb 2 S 3 , with and without the ultrathin ZnS interlayer, and with systematically varied Sb 2 S 3 thickness provides a complete picture of the physical processes at work in the devices., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)