Abstract
Perovskite solar cells have received considerable attention in recent years as a promising material capable of developing high performance photovoltaic devices. The efficiency of perovskite solar cells has increased to 20.1% from an initial 3.8% within 5 years. However, until now there is no study can directly observe the formation mechanism of Perovskite in nano scope. Therefore, in this research we developed home-made TEM liquid holder and with flow cell chip to study this issue. This research consists of three sections: (1) Observing nano-particle move via liquid injection, that could be initially confirmed the availability of TEM liquid holder. (2) Observing an aqueous solution of hydrogen peroxide catalyzed by Platinum is decomposed to oxygen nano-bubble movement and merging, that could confirm dynamic motion and chemical reaction are allowed in this system. (3) Successfully level up the resolution to atomic scale (Å) via using special way to control the liquid thickness in order to obtain the transformation of lattice structure in real time. Then in situ observing the process of lead iodide (PbI2) and Methyl ammonium iodide(MAI) to form MAPbI3 (CH3NH3PbI3). Our work not only demonstrates the feasibility of home-made TEM liquid holder but also bridge the in-situ TEM technique with the field of novel energy material synthesis so that make contribution to critical scientific issues.