Effect of Annealing on Innovative CsPbI3-QDs Doped Perovskite Thin Films

Abstract

In this study, a simple hot-injection method to synthesize high-quality inorganic perovskite cesium lead iodide (CsPbI3) quantum-dots (QDs) was demonstrated. Adding CsPbI3 QDs into the organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a composite perovskite film, annealed by different temperatures, was found to be effectively enhanced by the perovskite crystallization. The intensity of the preferred peak (110) of MAPbI3 was enhanced by increasing the size of the crystal and reducing the cluster crystal. The densest film can be found at annealing temperature of 140 °C. The full width half maximum of MAPbI3 and CsPbI3 was analyzed through XRD peak fitting. This was a huge breakthrough for QDs doped perovskite films.

Effect of Growth Temperature on the Characteristics of CsPbI3-Quantum Dots Doped Perovskite Film

“…As shown in Figure 1 a, when the filming temperature is 80–100 °C, pristine MAPbI 3 can still show a typical perovskite absorption spectrum; however, when the filming temperature is further heated to 120–140 °C, the pristine MAPbI 3 shows a significant decrease in the absorption spectrum, and the decomposed to PbI 2 phase dominated. The decomposition of MAPbI 3 can change from dark brown to yellow, similar to previous reports [ 11 , 12 ]. Figure 1 b shows the absorption spectrum for CsPbI 3 -QD doped perovskite thin films.…”

“…In addition, after increasing the filming temperature, the absorption area increases significantly in the entire spectral range (350–850 nm), and the long-wavelength absorption (750 nm) is significantly improved. This is because the energy gap of CsPbI 3 QD is wider and a small strain occurs at the QDs–MAPbI 3 interface [ 12 , 13 , 14 ]. Therefore, adding CsPbI 3 QDs can not only stabilize the MAPbI 3 film at a higher filming temperature, but also improve the absorption of the film at long wavelengths, and further enhance the absorption capacity of CsPbI 3 -QD doped perovskite thin films in the active layer of perovskite solar cells.…”

“…Figure 2 b shows the details of the preferred peaks of the QD doped film. According to previous research, it is found that when the filming temperature is up to 140 °C, the ratio of the peak area CsPbI 3 /MAPbI 3 is close to 1 and the perovskite crystallinity is optimal [ 12 ].…”

“…The experimental method is the modified hot-injection method previously reported [ 12 ]. All experiments were performed in a glove box filled with nitrogen, H 2 O < 1 ppm and O 2 < 1 ppm.…”

Recent advances on two-dimensional metal halide perovskite x-ray detectors

“…After centrifugation at 1000 rpm for 10 min to discard the precipitates, the bright yellow supernatant was collected to obtain the colloidal solution. Huang's group [67] produced CsPbI 3 quantum dots (QDs) of different sizes by the modified hot-injection method. They used the glove box system to create an anhydrous and oxygenfree environment.…”