Influence of the reagents’ ratio on photoelectric and optical properties of perovskite films for photovoltaics

Abstract

The properties of the synthesized films of organic-inorganic perovskites CH3NH3PbI3 obtained at various ratios of starting reagents (PbI2 and CH3NH3I) have been studied. As a solvent, we used chemically pure dried dimethylformamide (DMF). Organic-inorganic perovskites are promising for photovoltaic applications. It has been shown that regardless of the ratio of the starting reagents, single-phase perovskites are formed, at the same time the microstructure of the films changes significantly. It has been reported photoelectric and optical properties of synthesized films, namely: experimental and theoretical spectral dependences of the low-signal surface photovoltage and transmission. The band gap and the Urbach parameter dependence on the ratio of precursors were determined. It has been found that the materials’ band gap depends on the ratio of precursors and equals to 1.59, 1.62 and 1.57 eV, while the characteristic Urbach energy equals to 18, 19 and 22 meV for the PbI2:CH3NH3I films with PbI2 ratio of 1:1, 1:2 and 1:3, respectively. It has been ascertained that the spectral dependences of the low-signal surface photovoltage are much more sensitive to the material microstructure and its electronic structure close to the absorption edge, while the optical transmission spectra are not so sensitive. The limiting value of the short-circuit current density for the films with different PbI2 and CH3NH3I ratios has been determined.

Untitled

“…Non-Si solar cells were also considered, namely with perovskite thin films [21] and CdS/CIGS heterojunctions [22]. In [21], the properties of organic-inorganic cladcrystalline CH3NH3PbI3 thin films synthesized at different ratios of the starting reagents (PbI2 and CH3NH3I) were studied.…”

“…Non-Si solar cells were also considered, namely with perovskite thin films [21] and CdS/CIGS heterojunctions [22]. In [21], the properties of organic-inorganic cladcrystalline CH3NH3PbI3 thin films synthesized at different ratios of the starting reagents (PbI2 and CH3NH3I) were studied. The results showed that, regardless of the starting reagents ratio, single-phase crystalline inclusions form and the film microstructure significantly changes.…”

“…This area is the closest to SPQEO and includes photonics technologies, electric battery technologies, quantum technologies, and microelectronics. We have already mentioned sensors for medical monitoring, environmental protection, converting sunlight into electricity, and more [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. As an example, quantum technologies are presented in [28].…”

INFLUENCE OF THE SOLVENT AND THE RATIO OF STARTING REAGENTS ON THE PROPERTIES OF ORGANIC-INORGANIC PEROVSKITE MAPbI3

“…Nowadays, the best laboratory samples of elements based on perovskite demonstrate high efficiency and a low cost of their production. However, they have relatively low stability, although some solar cells show stable operation throughout the year [11,12]. This work aims to study the peculiarities of perovskite formation, and structural and electrophysical characteristics of organic-inorganic MAPbI 3 perovskite films depending on the solvent and the ratio of starting reagents.…”