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Solution-processed mixed halide CH3NH3PbI3−xClx thin films prepared by repeated dip coating
- Karim, A. M. M. Tanveer, Hossain, M. S., Khan, M. K. R., Kamruzzaman, M., Rahman, M. Azizar, Rahman, M. Mozibur
- Journal of materials science 2019 v.54 no.18 pp. 11818-11826
- X-ray diffraction, absorbance, ambient temperature, chemical bonding, coatings, crystals, emissions, energy, photoluminescence, scanning electron microscopy
- The mixed halide CH₃NH₃PbI₃₋ₓClₓ crystalline thin film has been prepared by two-step solution-processed repeated dip coating method at an ambient atmosphere. X-ray diffraction study reveals the presence of tetragonal and cubic phases in deposited film. Raman study confirms the metal halide bond in the inorganic framework and organic CH₃ stretching/bending of C–H bond in CH₃NH₃PbI₃₋ₓClₓ perovskite. Scanning electron microscopy shows that cuboid and polyhedral-like crystal grains of 100 nm to 2 μm may find applications in optoelectronics. The perovskite CH₃NH₃PbI₃₋ₓClₓ thin film shows high spectral absorption coefficient of the order of 10⁶ m⁻¹. In optical band gap study, we found the coexistence of cubic and tetragonal perovskite phases. The energy band gap is dominated by cubic phase having Eg = 2.50 eV over tetragonal phase with band gap Eg = 1.67 eV. The room-temperature photoluminescence study confirms band edge, shallow and deep-level emissions. The temperature-dependent cathodoluminescence study shows red, green and ultraviolet emissions. The dominating green luminescence evolved for cubic phase at 2.51 eV. The red and ultraviolet emissions are also found for mixed-phase CH₃NH₃PbI₃₋ₓClₓ thin film, suitable for preparation of light-emitting devices.