  Photoelectric conversion efficiency of organic-inorganic perovskite solar
cells has been rapidly raised and attracted great attention in recent years.
The quality of perovskite films is vital for the performance of devices. We
used the anti-solvent method to prepare CH$_3$NH$_3$PbI$_3$ thin films by spin
coating and dried them at various temperature to transform adduct
MAI.PbI$_2$.DMSO into CH$_3$NH$_3$PbI$_3$. We researched in detail on the
relationship between surface morphology of MAPbI$_3$ thin films fabricated by
the anti-solvent method and various drying temperature. We found that surface
roughness and grain size of CH$_3$NH$_3$PbI$_3$ films together increased with
increasing drying temperature. The larger grain size could efficiently reduce
crystal boundaries which is advantageous for the suppression of photo-induced
charge carrier recombination resulting in increase of FF. However, increase of
surface roughness resulted in larger contact area at interface which might
produce more tarp states and poorer wettability of HTM solution leading in
decrease of Jsc. Surface morphology of MAPbI3 layer on the performance of solar
cell devices is also an important research issue. By optimizing the drying
temperature to 60 oC, the highest efficiency of 14.4% was achieved for the
CH3NH3PbI3-based solar cell devices.
