Formamidinium Lead Iodide Perovskite Films with Polyvinylpyrrolidone Additive for Active Layer in Perovskite Solar Cells, Enhanced Stability and Electrical Conductivity

Abstract

In this paper, we studied the influence of polyvinylpyrrolidone (PVP) as a stabilization additive on optical and electrical properties of perovskite formamidinium lead iodide (FAPI) polycrystalline thin films on ZnO nanorods (ZNR). FAPI (as an active layer) was deposited from a single solution on ZNR (low temperature processed electron transport layer) using a one-step method with the inclusion of an anti-solvent. The role of PVP in the formation of the active layer was investigated by scanning electron microscopy and contact angle measurements to observe the effect on morphology, while X-ray diffraction was used as a method to study the stability of the film in an ambient environment. The effect of the PVP additive on the optical and electrical properties of the perovskite thin films was studied via photoluminescence, UV-Vis measurements, and electrical impedance spectroscopy. We have demonstrated that PVP inclusion in solution-processed perovskite FAPI thin films prevents the degradation of the film in an ambient atmosphere after aging for 2 months. The inclusion of the PVP also improves the infiltration of FAPI perovskite into ZnO nanostructures, increases electrical conductivity and radiative recombination of the photo-generated charge carriers. These results show promising information for promoting PVP stabilized FAPI perovskites for the new generation of photovoltaic devices.

Impedance Spectroscopy as a Powerful Tool for Researching Molybdenum-Based Materials with Schiff Base Hydrazones

“…Moving from DC to the dispersion region, the crossover shifts to higher frequencies as the temperature increases. Similar behavior in the conductivity spectra can be observed via IS in a wide range of semiconductive materials, amorphous and/or crystalline [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ].…”

Molybdenum Complexes Derived from 2-Hydroxy-5-nitrobenzaldehyde and Benzhydrazide as Potential Oxidation Catalysts and Semiconductors

“…The second one, at the highest temperatures and lowest frequencies, begins with the formation of a frequency-independent region (DC-part) that corresponds to the DC conductivity that arises from the translational motions of charge. Similar features in conductivity spectra can be observed via IS in a wide range of semiconductive materials, crystalline and/or amorphous [27,28,[33][34][35][36]. Owing to the lack of a discernible plateau in the graph, directly ascertaining the DC conductivity value from the plot is impractical.…”

Exploring Solar Cells Based on Lead- and Iodide-Deficient Halide Perovskite (d-HP) Thin Films

“…After 669 h, the (001) perovskite peak was greatly reduced, but the δ-d-FAPI-TEA peak did not increase in intensity, while new peaks appeared at 20.5°, 32.4°, 35.6° and 36.2° ( Figure 7 c), that we assign to Pb(OH)I phase formation, resulting in a pale white appearance of the film. [ 87 ] This compound, formed after the inclusion of hydroxide anions within the structure after a reaction between the perovskite and the humidity, was not observed for classic FAPI. After 882 h, no more δ-d-FAPI-TEA was present in the film and only a small amount of α-d-FAPI-TEA and Pb(OH)I was left.…”