Investigation of the Stability of Methylammonium Lead Iodide (MAPbI3) Film Doped with Lead Cesium Triiodide (CsPbI3) Quantum Dots under an Oxygen Plasma Atmosphere

Abstract

In this study, we describe composited perovskite films based on the doping of lead cesium triiodide (CsPbI3) quantum dots (QDs) into methylammonium lead iodide (MAPbI3). CsPbI3 QDs and MAPbI3 were prepared by ligand-assisted re-precipitation and solution mixing, respectively. These films were optimized by oxygen plasma treatment, and the effect of powers from 0 to 80 W on the structural properties of the composited perovskite films is discussed. The experimental results showed that the light-harvesting ability of the films was enhanced at 20 W. The formation of the metastable state (lead(II) oxide and lead tetroxide) was demonstrated by peak differentiation-imitating. A low power enhanced the quality of the films due to the removal of organic impurities, whereas a high power caused surface damage in the films owing to the severe degradation of MAPbI3.

The Influence of Oxygen Plasma on Methylammonium Lead Iodide (MAPbI3) Film Doped with Lead Cesium Triiodide (CsPbI3)

“…Furthermore, it is shown that oxygen is a method to suppress nonradioactive recombination and to improve the photovoltaic performance [ 24 ]. The plasma treatment also caused the decrease in the grain boundary of the MAPbI 3 film, which can be seen in a previous study [ 10 ]. With the decrease in the grain boundaries, the scattering of charge carriers reduced and the mobility of the film increased [ 25 ].…”

“…In Table 1 , the mobility of the MAPbI 3 doped with CsPbI 3 QDs was higher than that of the pure MAPbI 3 film. The stability could be improved by doping with CsPbI 3 QDs, and the number of defects on the film can be decreased, leading to the higher mobility [ 10 ]. For the analysis of the conduction mechanism, the mobility and the carrier concentration were measured through Hall effect measurement.…”

“…However, an excessive supply of oxygen plasma with power over 20 W caused the formation of bonds between carbon, lead and oxygen. This effect leads to the degradation of MAPbI 3 [ 10 , 15 ], and therefore the mobility dropped from 6.06 × 10 3 to 1.08 × 10 4 cm 2 /V s . Compared to the untreated film, the carrier concentration of the treated MAPbI 3 film was also enhanced.…”

“…Figure 4 shows the mobility and carrier concentration of different films treated with various powers of oxygen plasma from 0 to 80 W. It can be observed that the mobility was enhanced for 20 In Table 1, the mobility of the MAPbI 3 doped with CsPbI 3 QDs was higher than that of the pure MAPbI 3 film. The stability could be improved by doping with CsPbI 3 QDs, and the number of defects on the film can be decreased, leading to the higher mobility [10]. For the analysis of the conduction mechanism, the mobility and the carrier concentration were measured through Hall effect measurement.…”

“…However, excess oxygen ions cause oxidation and ion bombardment [ 9 ], leading to a decrease in the stability and structural destruction of the film. Thus, cesium triiodide (CsPbI 3 ) quantum dots (QDs) were doped into the MAPbI 3 film to achieve anion exchange in order to make the overall structure more stable [ 10 ], and the absorption was enhanced due to the unique optical properties of the QDs. In addition, the power of the oxygen plasma was tuned to investigate its influence on the MAPbI 3 .…”