CH3NH3PbI3-XCl2 Perovskite Solar Cell Grown by Interdiffusion of Stacking Layers
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Abstract
Organometalic halide perovskites in last two years have emerged as new class of light absorbers that have
demonstrated exceptional progress in solar cell performance [1]. To overcome pinholes problem in
CH3NH3PbI3-xClx we have been used modified interdiffusion method [2]: on patterned ITO coated glass after
cleaning it in chloroform, deionized water, acetone and 2-propanol in an ultrasonic bath for a 15 min each; aqueous
PEDOT:PSS layer was spin coated at 8000 rpm for 50 s. After heating this layer at 140◦C for 30 min the mixture of
PbI2 and PbCl2 (with molar ratio 3.4) dissolved in DMF and DMSO mixture with molar ratio 3 was spin coated at a
rate 6000 rpm at 65◦C using 65◦C hot solution and was dried at 70◦C in argon atmosphere for 45 minutes. On top of
this layer CH3NH3I solution in 2-propanol (40 mg/mL) was spin coated at a rate 6000 rpm at 65◦C. The obtained
bilayer system was annealed in closed system at 107◦C for 1 h and additionally 1 h in argon atmosphere. After
cooling to room temperature system was covered with PCBM dissolved in DCB (30 mg/mL) at a rate 2000 rpm for
60 s and annealed in argon atmosphere at 105◦C for 1 h, cooled down and put in vacuum chamber where 50 nm
thick C60 layer and 60 nm thick Ag electrode were thermally evaporated at pressure 10-6 mbar.
All photoelectric measurements have been made in the same homemade vacuum cryostat where electrode
was deposited at p~5∙10-7 mbar without breaking the vacuum and moving the cell. The spectral dependences of short
circuit photocurrent external quantum efficiency (EQE), fill factor (FF) and open circuit voltage (VOC) has been
investigated in spectral range 370-900 nm, using synhro-detection technique and PC controlled data storage
equipment