Method for preparing light absorber of solar cell

A method for preparing a light absorber of a solar cell, comprising the steps of:

• applying, on an electrode (step 1),
• step 1(a) coating an adduct of i) a compound represented by Chemical Formula 1, and ii) a polar aprotic solvent containing a NH or NCH3 structure in a solvent different from the polar aprotic solvent in the adduct, and
• step 1(b) coating a solution containing one or two types of compounds represented by Chemical Formula 2,
• wherein step 1(a) and step 1(b) are preformed sequentially;
• and
• heat-treating the electrode of step 1 (step 2):
• MXX′ [Chemical Formula 1]
• in Chemical Formula 1,
• M is a divalent metal cation,
• X and X′ are each independently the same or different halogen;
• AX″ [Chemical Formula 2]
• in Chemical Formula 2,
• A is an organic cation of R1R2R3R4N+, or (R5R6N═CH—NR7R8)+,
• wherein R1, R2, R3 and R4 are each independently hydrogen, or Cl1-10 alkyl, with the proviso that at least one of R1, R2, R3 and R4 is C1-10 alkyl,
• R5, R6, R7 and R8 are each independently hydrogen, or C1-10 alkyl, and
• X″ is halogen.