ABSTRACT
Atomic-force microscopic images, x-ray diffraction patterns, Urbach energies and photoluminescence quenching experiments show that the interfacial contact quality between the hydrophobic [6,6]-phenyl-C61-buttric acid methyl ester (PCBM) thin film and hydrophilic CH3NH3PbI3(MAPbI3) thin film can be effectively improved by using a binary antisolvent mixture (toluene:dichloromethane or chlorobenzene:dichloromethane) in the anti-solvent mixture-mediated nucleation process, which increases the averaged power conversion efficiency of the resultant PEDOT:PSS (P3CT-Na) thin film based MAPbI3solar cells from 13.18% (18.52%) to 13.80% (19.55%). Beside, the use of 10% dichloromethane (DCM) in the binary antisolvent mixture results in a nano-textured MAPbI3thin film with multicrystalline micrometer-sized grains and thereby increasing the short-circuit current density and fill factor (FF) of the resultant solar cells. It is noted that a remarkable FF of 80.33% is achieved, which can be used to explain the stable photovoltaic performance without additional encapsulations.
ABSTRACT
The averaged power conversion efficiency of polyelectrolytes (P3CT-Na) based MAPbI3solar cells can be increased from 14.94% to 17.46% with a wetting method before the spin-coating process of MAPbI3precursor solutions. The effects of the wetting process on the surface, structural, optical and excitonic properties of MAPbI3thin films are investigated by using the atomic-force microscopic images, x-ray diffraction patterns, transmittance spectra, photoluminescence spectra and Raman scattering spectra. The experimental results show that the wetting process of MAPbI3precursor solution on top of the P3CT-Na/ITO/glass substrate can be used to manipulate the molecular packing structure of the P3CT-Na thin film, which determines the formation of MAPbI3thin films.
