15:10 〜 15:25
▲ [18p-145-5] Real-time TEM observation of thermally induced degradation in organometal halide perovskite
キーワード：Organometal halide perovskite, Thermal degradation, Transmission electron microscopy
Organometal halide perovskite has shown remarkable achievements in solar cell applications and has attracted tremendous attention as next-generation photovoltaic materials. Recently, the highest power conversion efficiency (PCE) of organometal halide perovskite solar cells (PSCs) using mixed organic cations and halide anions has reached to 22.7%. The conspicuous performance of PSCs is attributed to the special characteristics of the perovskite light absorbers and the development of various solar cell fabrication methods. However, the unprecedented results of PSCs have been obtained under well-controlled laboratory conditions managed to minimize degradations of the perovskite caused by moisture, oxygen, UV light, and heat. For commercialization in solar cell applications, sustainable stability is as important as high PCE, however the perovskite light absorbers do not meet both requirements in practical situations because of the degradations. Hence, the investigation of the degradations of the organometal halide perovskite is considered as important areas of research, however the details of the degradations are not fully understood yet. In this respect, we investigated detailed procedure of thermal degradation, one of the most critical obstacles for commercialization of PSCs, using real-time in situ transmission electron microscopy (TEM).
From the real-time in situ TEM observation, we directly confirmed the detailed process of precipitating trigonal PbI2 grains during thermal degradation and revealed that the trigonal PbI2 is precipitated from amorphized MAPbI3 layer via intermediate states. Interestingly, the intermediate states and their stackings induce three-dimensional linear passages that can be utilized as paths by elements during the decomposition and intercalation of the organometal halide perovskite.
From the real-time in situ TEM observation, we directly confirmed the detailed process of precipitating trigonal PbI2 grains during thermal degradation and revealed that the trigonal PbI2 is precipitated from amorphized MAPbI3 layer via intermediate states. Interestingly, the intermediate states and their stackings induce three-dimensional linear passages that can be utilized as paths by elements during the decomposition and intercalation of the organometal halide perovskite.