title: Enhanced performance of CH3NH3PbI3-x Cl x perovskite solar cells by CH3NH3I modification of TiO2-perovskite layer interface.
abstract: In this work, perovskite solar cells (PSCs) with CH3NH3PbI3-x Cl x as active layer and spiro-OMeTAD as hole-transport media have been fabricated by one-step method. The methylammonium iodide (CH3NH3I) solution with different concentrations is used to modify the interface between mesoporous TiO2 (meso-TiO2) film and CH3NH3PbI3-x Cl x perovskite layer. Several techniques including X-ray diffraction, scanning electron microscopy, optical absorption, electrochemical impedance spectroscopy (EIS) and photoluminescence are used to investigate the effect of the interfacial modification. It is found that the interfacial modification by CH3NH3I enhance the crystallinity and increase the grain size of CH3NH3PbI3-x Cl x layer, and improve the surface wetting properties of perovskite precursor on meso-TiO2 film. The sunlight absorption and external quantum efficiency of PSCs in the visible region with wavelength less than 600 nm have been improved. The Nyquist plots obtained from the EIS suggest that the CH3NH3I modification can reduce the charge recombination rates. The photoluminescence measurement shows that the exciton dissociation in the modified devices is more effective than that in the control samples. The photovoltaic performance of the modified devices can be significantly improved with respect to the reference (control) devices. The CH3NH3I modified devices at the optimized concentration demonstrate the average power conversion efficiency of 12.27 % in comparison with the average efficiency of 9.68 % for the reference devices.
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Zongbao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Jinshan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Jianming
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Riyan
authors.initials: R
authors.lastname: Huang
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Xubing
authors.initials: X
authors.lastname: Lu
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.
authors.forename: Xingsen
authors.initials: X
authors.lastname: Gao
authors.affiliation: South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Shui
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China. sujwu@scnu.edu.cn.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Wu
authors.affiliation: Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.|Laboratory of Solid State Microstructures, Nanjing University, Nanjing, 210093, China.
authors.forename: Jun-Ming
authors.initials: JM
authors.lastname: Liu
keywords: CH3NH3I; CH3NH3PbI3−x Cl x perovskite solar cells; Interfacial modification; Performance; Photoelectronic properties