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The surface morphologies, crystallinities, and excitonic characteristics of MAxCs1−xPb(IxBr1−x)3 thin films deposited on top of the P3CT‐Na/ITO/glass substrates are investigated by using the atomic‐force microscopic images, absorbance spectra, grazing incidence X‐ray diffraction patterns, photoluminescence (PL) spectra, and Raman scattering spectra. The P3CT‐Na‐based perovskite solar cell shows a stable and efficient maximum power density curve due to the formation of a graded MA0.83Cs0.17Pb(I0.83Br0.17)3 alloy thin film which is confirmed by using the surface‐sensitive PL and Raman scattering spectra. The highest power conversion efficiency (PCE) of the P3CT‐Na‐based MA0.83Cs0.17Pb(I0.83Br0.17)3 solar cells is 15.93% mainly due to the high fill factor of 79.4%. Besides, the PCE of the nonencapsulated solar cell slowly decreases to a moderate value (10.48%) within 157 days under an uncontrolled environment (55–60 relative humidity%) at room temperatures (22–25 °C). [ABSTRACT FROM AUTHOR]

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 MAPbI3 solar 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 MAPbI3 thin 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 FROM AUTHOR]

The averaged power conversion efficiency of polyelectrolytes (P3CT-Na) based MAPbI3 solar cells can be increased from 14.94% to 17.46% with a wetting method before the spin-coating process of MAPbI3 precursor solutions. The effects of the wetting process on the surface, structural, optical and excitonic properties of MAPbI3 thin 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 MAPbI3 precursor 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 MAPbI3 thin films. [ABSTRACT FROM AUTHOR]

Transmittance spectra, atomic-force microscopic images, energy-dispersive X-ray spectra and droplet contact angle images show that a facile wet etching process can be used to manipulate the thickness, surface roughness, surface chemical composition and surface wettability of the indium-tin oxide (ITO) thin films, which influences the molecular packing structure of the P3CT-Na thin films and thereby dominating the crystal quality of the CH 3 NH 3 PbI 3 (MAPbI 3) thin films. The power conversion efficiency (PCE) of the P3CT-Na based MAPbI 3 solar cells can be improved from 17.02% to 19.35% by increasing the Sn/In concentration ratio of the ITO thin films from 0.36 to 0.47 with a facile wet etching process at a constant temperature of 40 °C. It is noted that the PCE of the optimal solar cell decreases slowly toward a stable PCE of 16% for more than 60 days under moderate environment conditions (55 ± 10 RH%). • Surface properties of the ITO/glass substrates can be varied by the wet etching process. • The contact quality at the P3CT-Na/ITO interface can be improved. • The contact quality at the MAPbI3/P3CT-Na interface can be improved. • After 60 days, the PCE slowly decreased from 19.35% to 16.03%. [ABSTRACT FROM AUTHOR]