The Deposition Environment Controlling Method: A Vapor-Phase Solvent-Assisted Approach to Fabricate High-Quality Crystalline Perovskite

The deposition environment controlling (DEC) method is explored to enhance the carrier-extracting ability of a light-absorbing layer for perovskite solar cells. Inspired by the solvent engineering, the DEC method, an exquisite-controlled approach, is applied in vapor deposition for generating the CH
₃
NH
₃
PbI
₃
. This method not only gives the excellent uniformity, coverage of the film, and glove box free for all the solutionbased and annealing steps, but also provides an easy but accurate control of the additive solvent, compared with the traditional solvent engineering. Here, chlorobenzene (CB) is introduced to the sandwich deposition technique process. The vaporized CB, which does not dissolve CH
₃
NH
₃
I, PbI
₂
, and CH
₃
NH
₃
PbI
₃
, offers a thermodynamic driving force to rapidly and continuously generate CH
₃
NH
₃
PbI
₃
without forming the intermediate phase. The homogenous film and less defects of crystalline perovskite are yielded. As a result, the maximum grain size exceeds 1 μm along the lateral direction and significantly improves the hole-electron dissociation. V
_oc
is improved to 0.99 V, J
_sc
to 18.89 mA/cm
²
, and fill factor to 79.03%, yielding a 14.62% efficiency.