  The optical amplification emission of hybrid lead perovskite attracted great
research interests. We systematically examined and compared temperature
dependent optical amplification behavior of a series of organic-inorganic
hybrid perovskite films of (MA/FA)Pb(Br/I)3. The optical amplification
threshold of the films showed considerable exponential increase towards the
temperature increasing. We figured out that the critical temperature for the
four films presented a sequence of FA+I < MA+I < FA+Br < MA+Br. Our
systematical study is crucial for in depth understanding the fundamental
mechanism of amplified emission of hybrid perovskite materials.
