Organic-inorganic hybrid perovskite solar cells processed with Br or Cl doping via a two-step deposition

Abstract

Mixed halide perovskites of MAPbI3-xBrx and MAPbI3-xClx (MA = CH3NH3) with film thickness of about 300 nm were synthesized through the Br or Cl doping, thanks to the two steps deposition of controlled concentration of the precursor solution and the intramolecular exchange of DMSO molecules intercalated in PbI2 (PbI2(DMSO) complex) with MAX (X = I, Br) or MAX (X = I, Cl), respectively. The doping of Br or Cl in the perovskite film can improve the photovoltaic performance of PSCs with the precursor of MAX contains 5% (in mole fraction, same below) MABr or 15% MACl, respectively, while further increase in the content of MABr or MACl in the precursor did not lead to significant changes in doping amounts, but small white particles or pin-holes were formed in mixed perovskite materials, therefore resulted in adverse effects on the performance of solar cells. The MAPbI3-xBrx perovskite solar cells with 5% MABr in precursor solution showed a power conversion efficiency (PCE) of 13.2%, and the MAPbI3-xClx perovskite solar cells with 15% MACl in precursor solution showed the highest PCE of 13.5%.