Methods for Making Perovskite Solar Cells Having Improved Hole-Transport Layers

An aspect of the present disclosure is a device that includes a first layer that includes a hole-transport material and an acid, where the first layer has a conductivity between 20 Mu Siem and 500 Mu Siem. In some embodiments of the present disclosure, the first layer may absorb light having a wave-length between 400 nm and 600 nm. In some embodiments of the present disclosure, the hole-transport material may include at least one of 2,2',7,7'-tetrakis(N,N-di-p-methoxy-phenylamine)-9 ,9'-spiro bifluorene (spiro-0 Me TAD), a derivative of spiro-OMeTAD, poly(triarylamine), poly(3-hexylthiophene), and/or N,N'-bis(3-methylphenyl)-N,N'-di-phenylbenzidine.