The Thermomechanical Properties of Thermally Evaporated Bismuth Triiodide Thin Films

Abstract

Bismuth triiodide (BiI 3 ) has been studied in recent years with the aim of developing lead-free semiconductors for photovoltaics. It has also appeared in X-ray detectors due to the high density of the Bismuth element. This material is attractive as an active layer in solar cells, or may be feasible for conversion into perovskite-like material (MA 3 Bi 2 I 9 ), being also suitable for photovoltaic applications. In this study, we report on the thermomechanical properties (stress, hardness, coefficient of thermal expansion, and biaxial and reduced Young’s moduli) of BiI 3 thin films deposited by thermal evaporation. The stress was determined as a function of temperature, adopting the thermally induced bending technique, which allowed us to extract the coefficient of thermal expansion (31 × 10 −6 °C −1 ) and Young’s biaxial modulus (19.6 GPa) for the films. Nanohardness (~0.76 GPa) and a reduced Young’s modulus of 27.1 GPa were determined through nanoindentation measurements.

Self-biased photodetector using 2D layered bismuth triiodide (BiI3) prepared using the spin coating method

“…The obtained values of lattice constants are a ∼ 5.327 Å, c ∼ 21.051 Å and V = 597.36 Å 3 . These values match well with previously reported data, 41–43 further confirming the formation of BiI 3 films. The average grain size ( d X-ray ) of BiI 3 films was determined from the (003)/(113) plane located at 2 θ ∼ 12.06°/26.8° using Debye–Scherrer's equation, 44 where λ indicates the wavelength, β represents full width at half maximum (FWHM), and θ represents Bragg's diffraction angle.…”

Recent Development of Halide Perovskite Materials and Devices for Ionizing Radiation Detection

“…92 Schuyt et al further prepared NaMgF 3 (Mn) and explored the effect of ionizing radiation on the optical properties. 277 278 BiI 3 has been studied for X-ray detectors due to the high atomic number of the Bismuth element and its feasibility for conversion into perovskite-like MA 3 Bi 2 I 9 . 141 Another significant merit of perovskite films is the superior flexibility, enabling their utilization in various wearable X-ray detector devices due to the lightweight nature and ability to adhere to uneven surfaces conformably.…”

“…Through optimization of spraying parameters, they successfully synthesized dense and uniform Cs 2 TeI 6 thick films using an electrical bias of 10 kV with DMF as the solvent, and a recorded substrate temperature of 160 °C. Coutinho et al investigated the thermomechanical properties of BiI 3 thin films . BiI 3 has been studied for X-ray detectors due to the high atomic number of the Bismuth element and its feasibility for conversion into perovskite-like MA 3 Bi 2 I 9 …”

Design and Simulation of Lead-free Flexible Perovskite Solar cell Using SCAPS-1D.

“…Furthermore, because of its non-toxicity, high absorption coefficient, narrow bandgap (1.72 eV), and short carrier lifetimes, bismuth iodide (BiI3) material has been receiving increasing attention. Because of these characteristics, BiI3 may be more suitable for solar applications [9]. Recently, Y. Hu et al fabricated a PSC device with pure BiI3 over the titanium oxide ETL and achieved an enhanced electron transport behaviour by passivating the interfacial trap states.…”