Low-Temperature Ionic Layer Adsorption and Reaction Grown Anatase TiO2 Nanocrystalline Films for Efficient Perovskite Solar Cell and Gas Sensor Applications

Abstract

A low-temperature (90 °C) and directly grown anatase titanium dioxide (TiO2) nanocrystalline film using successive ionic layer adsorption and reaction (SILAR) for perovskite solar cell and gas sensor applications. TiO2 nanocrystalline electron transfer layer (ETL) improves the power conversion efficiency (PCE) of perovskite solar cells due to faster charge transport kinetics as well as slower charge recombination process. The optimized TiO2 nanocrystalline ETL (15 L) demonstrates as high as ~10% PCE with a short circuit current density of 18.0 mA/cm2, open circuit voltage of 0.81 V and fill factor of 66.3% in perovskite solar cells. Furthermore, room-temperature ammonia sensing characteristics of TiO2 nanocrystalline film (25 L) were demonstrated for various concentration levels of ammonia in dry air conditions. A high room-temperature response of 80% was achieved at 100 ppm of ammonia with rapid response and recovery signatures of 30 and 85 s, and nearly fifteen days stability, respectively. The response of the sensor to other gases such as formaldehyde, petrol, ethanol acetone, and ammonia etc, indicated a high selectivity towards volatile organic compounds of ammonia gas. The room temperature operation, with high selectivity, repeatability and fast transition times, suggests potentially useful in flexible and cost-effective production in optoelectrochemical device technology.

Facet controlled growth mechanism of SnO2 (101) nanosheet assembled film via cold crystallization

“…Metal oxide nanostructures have been developed on fluorine-doped tin oxide (FTO) substrates for various devices such as chemical sensors 1 – 3 . In particular, a photoelectric conversion molecular sensor was recently proposed by combining a metal oxide nanostructured film with FTO 4 – 7 .…”

Evanescent wave ammonia sensor: influence of nanocrystalline TiO 2 on V 2 O 5 and MoO 3

“…2 c . The obtained electron diffraction pattern was indexed [21] with the anatase phase of TiO 2 and the rings are assigned to (101), (004), (200), and (105).…”

SILAR Deposition of Metal Oxide Nanostructured Films

“…Several studies describe the SILAR deposition of TiO 2 thin films assessing their crystallinity, porosity and opto-electronic behavior, for use in photocatalysis, [146][147][148] photovoltaics and gas sensors. [149,150] As a soft chemical synthesis technique, SILAR has been recognized as an ideal method for fabrication of nanocrystalline films with a high-surface area. [146] It is worth noticing that the vast majority of TiO 2 films and nanostructures in general are deposited via the sol-gel method, due to the availability of alkoxide precursors and their tunable reactivity [151,152] In most SILAR studies, chlorides of titanium have been utilized as a cationic precursor in highly acidic conditions to prevent excessive hydrolysis, and slightly basic water as the anionic precursor is used to trigger fast TiO 2 precipitation.…”