Towards green antisolvent for efficient CH3NH3PbBr3 perovskite light emitting diodes: A comparison of toluene, chlorobenzene, and ethyl acetate

Antisolvent engineering is one of the most widely used methods to obtain high quality perovskite films. This process involves the heavy use of toxic antisolvents, such as toluene (Tol) and chlorobenzene (CB). It is thus highly desirable to develop green antisolvents for the future manufacturing of perovskites. Though several green antisolvents have been developed for iodide perovskites, there are few reports about their application on bromide ones. Besides, the reported green antisolvents for iodide perovskites usually lead to a significant increase in the crystal size, which is not suitable for light emission due to reduced carrier confinement and radiative recombination. Here, we introduce green antisolvent ethyl acetate (EA) to prepare CH3NH3PbBr3 (MAPbBr3) perovskite films. In contrast to previously reported iodide perovskites, EA engineered MAPbBr3 only shows a slight increase in the crystal size. A systematic study on the structural, morphological, and optoelectronic properties of MAPbBr3 prepared with Tol, CB, and EA was carried out. With the benefits of relatively high polarity and low boiling point compared with Tol and CB, EA could extract the solvent more efficiently. This gives rise to MAPbBr3 films with increased crystallinity, improved morphology, and reduced defects, boosting the performance of the corresponding light emitting diodes (LEDs). Our study provides an environmentally friendly way to the manufacturing of efficient MAPbBr3 perovskite LEDs as well as other optoelectronic devices.