Reducing Defects in Organic-Lead Halide Perovskite Film by Delayed Thermal Annealing Combined with KI/I2 for Efficient Perovskite Solar Cells

Abstract

This study improved quality of CH3NH3PbI3 (MAPbI3) perovskite films by delaying thermal annealing in the spin coating process and introducing KI and I2 to prepare MAPbI3 films that were low in defects for high-efficiency perovskite solar cells. The influences of delayed thermal annealing time after coating the MAPbI3 perovskite layer on the crystallized perovskite, the morphology control of MAPbI3 films, and the photoelectric conversion efficiency of solar cells were investigated. The optimal delayed thermal annealing time was found to be 60 min at room temperature. The effect of KI/I2 additives on the growth of MAPbI3 films and the corresponding optimal delayed thermal annealing time were further investigated. The addition of KI/I2 can improve perovskite crystallinity, and the conductivity and carrier mobility of MAPbI3 films. Under optimized conditions, the photoelectric conversion efficiency of MAPbI3 perovskite solar cells can reach 19.36% under standard AM1.5G solar illumination of 100 mW/cm2.

Mixed Solvent Engineering for Morphology Optimization of the Electron Transport Layer in Perovskite Photovoltaics

“…25,44,45 However, for the CB 0 −DCB 1.0 processed ETL layer, the solvent annealing time of 10 min for elevated temperature of 120 °C is inadequate; additionally, some traces of solvent may leave within the interface owing to its lower vapor pressure and result in the formation of surface defects. 46 However, the surface roughness of CB 0 −DCB 1.0 is lower than that of CB 1.0 − DCB 0 since the dielectric constant value of DCB (9.93) is higher than that of CB (5.62), which resembles the higher degree of solubility, 30 and hence the ETL processed with DCB is smoother with reduced surface roughness than CB processed ETL.…”

“…In the present study, the ETL solvent annealing temperature is fixed to 120 °C for a duration of 10 min for quick annealing, which seems to be the optimized time period for mixed solvent processed PCBM films, where the presence of DCB retarded the rate of solvent evaporation and resulted in reduced surface roughness (shown in Figure b,c) and pinholes. The optimized ratio of high bp solvent in the mixed solvent system mitigates the degree of solvent volatilization and eases the formation of smooth and better quality films with reduced surface roughness by allowing the penetration of PCBM into perovskite voids. ,, However, for the CB 0 –DCB 1.0 processed ETL layer, the solvent annealing time of 10 min for elevated temperature of 120 °C is inadequate; additionally, some traces of solvent may leave within the interface owing to its lower vapor pressure and result in the formation of surface defects . However, the surface roughness of CB 0 –DCB 1.0 is lower than that of CB 1.0 –DCB 0 since the dielectric constant value of DCB (9.93) is higher than that of CB (5.62), which resembles the higher degree of solubility, and hence the ETL processed with DCB is smoother with reduced surface roughness than CB processed ETL.…”

In Silico Investigation of the Impact of Hole-Transport Layers on the Performance of CH3NH3SnI3 Perovskite Photovoltaic Cells

“…In recent years, perovskite solar cells (PSC) based on organometallic lead halides have emerged as strong competitors to silicon in the photovoltaic market [10][11][12], as well as an efficient technology to complement the silicon photovoltaic devices in tandem architecture [13][14][15]. These materials boast high efficiency (about 25%) at a fraction of the silicon device thickness, as well as ease of fabrication, making them highly promising for future photovoltaic applications [16][17][18][19][20][21][22]. One of the main downsides of these devices is that the best efficiencies have so far been demonstrated by organometallic lead halides which present a serious danger to the environment due to the toxicity of lead [23][24][25].…”

Antisolvent Engineering to Enhance Photovoltaic Performance of Methylammonium Bismuth Iodide Solar Cells

“…Metal-halide perovskites have drawn significant attention as one of the most promising next-generation photovoltaic materials due to their adjustable composition, direct bandgap, long carrier diffusion length, and outstanding optoelectronic properties [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Since 2009, the power conversion efficiency (PCE) has increased from 3.8% to 25.7% in 2022 [ 8 , 9 ].…”