Study of Annealing Temperature Effect on the Photovoltaic Performance of BiOI-Based Materials

Abstract

Bismuth oxyiodide (BiOI) is expected to be promising material for photovoltaic devices since it has good activity under the visible range. Here, we studied the annealing treatment on BiOI and its effect on the photovoltaic application. Firstly, the synthesized BiOI from Bi(NO3)3 and KI was annealed at varied temperatures (100–550 °C). The structural investigation by X-ray diffraction and Raman spectroscopy analysis was supported with morphology and optical analysis by scanning electron microscope (SEM) and UV-Visible spectroscopy. Due to the heating treatment, it could result in iodine-deficient bismuth-based materials, namely Bi7O9I3, Bi5O7I, and β-Bi2O3. Secondly, the photovoltaic test measurement was performed by solar simulator air mass (AM) 1.5 illumination which presented the current-voltage curve from each material. The enhancement of photovoltaic performance was given by the increase of temperature up to 300 °C. At that temperature, the performance of the device which consisted of Bi7O9I3 achieved three times higher efficiency than the annealed parent BiOI at 100 °C. Hence, the structural changing owing to the oxygen addition to BiOI structure had an impact on the photoelectrochemical cell. Based on this work, it is possible to attempt BiOI derivation with suitable holes and electron transport layers for better photovoltaic performance.

Alternative Bi precursor effects on the structural, optical, morphological and photocatalytic properties of BiOI nanostructures

“…The XRD patterns confirm the achievement of the desired BiOI stoichiometry, with tetragonal phase (PDF# 10-0445). This phase has been already reported by several groups but using mainly Bi(NO 3 ) 3 as bismuth source [5,[14][15][16][17], [25][26][27][28][29][30][31][32], most of them by hydrothermal methods. Therefore, the same crystalline phase can be obtained regardless of the used precursor; in our case, bismuth acetate (BiAc) and subsalicylate (BiSs) by a simpler hydrothermal route.…”

“…However, a more likely explanation for these peaks is that they appear due to the energy supplied locally by the laser irradiation during the Raman measurement, providing enough energy to induce changes in the crystalline phase [38]. There is a report showing that BiOI is sensible to thermal processes, losing I-atoms while gaining O-atoms simultaneously, as temperature increases until it is transformed to β-Bi 2 O 3 [30]; even at lower temperatures [39]. This increase of temperature could be explained by a poor thermal conductivity of the BiOI powders.…”

A simple spin-assisted SILAR of bismuth oxyiodide films preparation for photovoltaic application

“…We identified that our flaky structure is the same as the obtained morphology of prepared BiOI by other researchers. Flaky BiOI is considered as the basic shape of BiOI, and sometimes, it can be in the sheet-like material [15]. When the cycle reaction increases during the film preparation, it can result in the bigger flaky size of BiOI material which is shown by the lateral size of BiOI flake in (2) Bi 3+ + I − + H 2 O → BiOI + 2H + Fig.…”

“…Furthermore, BiOI can be successfully synthesized by successive ionic adsorption and reaction with dip-coating (dip-SILAR) [5,[8][9][10], chemical bath deposition (CBD) [11], chemical vapor transport [2,12], mechanical grinding [13], and solvothermal reaction [6,14]. Conventional dip-SILAR, CBD, and slip-casting from BiOI powder [15] are also common to obtain the BiOI films for photovoltaic application.…”

Synthesis and Enhanced Light Photocatalytic Activity of Modulating Band BiOBrXI1−X Nanosheets

“…Unlike some metal oxide semiconductors composed of O 2p orbitals, the valence band of the Bi-based photocatalyst is formed by the hybridization of Bi 6s and O 2p orbitals [17,18]. The orbital hybridization reduces the forbidden bandwidth and disperses the valence band, thereby enhancing the visible light absorption capacity, making holes easy to move on the valence band, and hindering the recombination of photogenerated holes and photogenerated electrons [19][20][21]. BiOI has a narrow bandgap (1.7-1.9 eV), which can cover the entire visible light region, showing effective visible light photocatalytic activity.…”