Abstract
Solvent engineering is one of the most widely applied preparation methods for the high- quality perovskite films. In this method, the choice of anti-solvent plays a very important role to improve the perovskite crystal quality. Here, we report a facile way to regulate the crystal quality of perovskite film by adjusting the ratio of toluene and diethyl ether in the mixed anti-solvent. Through the combination of characterization and measurements including scanning electron microscopy, the atomic force microscopy, X-ray diffraction, and the steady-state photoluminescence spectra, it reveals that the quality of perovskite films is obviously improved when the volume ratio of toluene to diethyl ether in the mixed anti-solvent is 1:1. The optimal device obtains power conversion efficiency of 16.96% with a short-circuit current density of 20.60 mA/cm2, an open-circuit voltage of 1.03 V, and a fill factor of 79.96%. At the same time, the device shows negligible current–voltage hysteresis and steady power output. Moreover, the stability of PSCs is significantly enhanced due to the perovskite film quality improvement by adopting 50% toluene mixed anti-solvent.
Highlights
By virtue of the excellent photoelectric properties of organic–inorganic hybrid perovskite materials, such as high absorption coefficient, ambipolar transport properties, balanced and long charge carrier diffusion length, tunable band gap, etc., the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has surged from 3% to 25.2% over the past decade [1,2,3,4,5,6,7,8,9,10]
Compared to the n-i-p configuration, the p-i-n PSCs, typically consisting of ITO/poly (3,4-ethylenedioxythiophene):poly (PEDOT:PSS)/Perovskite film/ [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/Ag, where PEDOT:PSS acts as the hole transporting layers (HTLs) and PCBM acts as the electron transporting layers (ETLs), have aroused a lot of attention recently due to less hysteresis effects, relatively low cost, low temperature process, and more compatible fabrication process with flexible substrate for Coatings 2019, 9, 766; doi:10.3390/coatings9110766
The results show that the perovskite films were more smooth and dense when the volume ratio of toluene to diethyl ether in the mixed anti-solvent is 1:1 through the methods of morphology characterization such as the scanning electron microscopy (SEM) and the atomic force microscopy (AFM)
Summary
By virtue of the excellent photoelectric properties of organic–inorganic hybrid perovskite materials, such as high absorption coefficient, ambipolar transport properties, balanced and long charge carrier diffusion length, tunable band gap, etc., the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has surged from 3% to 25.2% over the past decade [1,2,3,4,5,6,7,8,9,10]. PSCs with conventional n-i-p configuration readily achieve higher PCE [9,11,12]. Electron transporting layers (ETLs) for n-i-p configuration, such as TiO2 , require a high fabrication temperature of above 400 ◦ C and its hole transporting layers (HTLs), typically Spiro-MeOTAD, are synthesized by multiple steps and relatively expensive [11,13]. Compared to the n-i-p configuration, the p-i-n PSCs, typically consisting of ITO/poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS)/Perovskite film/ [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/Ag, where PEDOT:PSS acts as the HTL and PCBM acts as the ETL, have aroused a lot of attention recently due to less hysteresis effects, relatively low cost, low temperature process, and more compatible fabrication process with flexible substrate for Coatings 2019, 9, 766; doi:10.3390/coatings9110766 www.mdpi.com/journal/coatings
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