| Since the perovskite solar cells（PSCs）were first studied in 2009,the power conversion efficiency of PSCs has exceeded 23%after rapid development,showing great commercial potential.The Cs/FA/MA triple-cation perovskite is considered as an effective strategy for the preparation of high efficiency perovskite solar cell devices due to its suitable band gap,excellent thermal stability and repeatability.However,the introduction of Cs atoms tends to decrease the grain size of the film and increase the grain boundaries,which can cause the problems such as increased carrier recombination and reduced diffusion distance in the device.In addition,as the two major problems of perovskite,hysteresis and environmental instability are also ubiquitous in Cs/FA/MA triple cations perovskite devices,hindering the commercial development of perovskite solar cells.In this thesis,my topic is focused on the Cs/FA/MA triple cations perovskite solar cells.The triple-cation perovskite was modified by doping chlorine in the precursor solution to increase the grain size and crystallization of perovskite.The hysteresis behavior was effectively suppressed due to this novel method.In addition,the interface engineering was used to modify the interface of perovskite/HTL.The P-type material10-（4-（4,6-diphenyl-1,3,5-triazin-2-yl）phenyl）-9,9-dimethyl-9,10-dihydroacridine（DMAC-TRZ）and organic amine salt phenylbutylamine iodide（PBAI）are used as the interfacial layer to enhance the humility stability of the triple-cation perovskite solar cells.The main contents of this thesis are listed as following:1.Hysteresis behavior of devices was significantly suppressed by the halide incorporation method.The molar ratio of MABr and PbCl2 in the precursor is adjusted to optimize the doping amount of chlorine.The incorporation of Cl in triple-cation perovskite effectively optimized the crystallization process of perovskite and improved the crystallinity of perovskite film,which increased the life time of carries.In addition,the grain size of the perovskite film is increased from less than 500 nm to nearly 1μm,and the grain boundaries were significant decreased.The photoelectric conversion efficiency of small area perovskite solar cells based on mesoporous TiO2 was increased from 18.09%to 19.14%,and the hysteresis index was reduced from 0.174 to 0.082.A5×5 cm2 large area perovskite solar cells was then fabricated and the photoelectric conversion efficiency reached 15.11%.In addition,the humidity stability of the device with the Cl-doped was also improved.The device based on the mesoporous TiO2 can maintain 90%of the initial efficiency after stored at 25°C and 40%relative humidity（RH）for 600 h.2.P-type material DMAC-TRZ was employed as the interface layer to modify the perovskite/hole transport layer interface.The concentration of DMAC-TRZ solution was adjusted to control the thickness of the interface layer.The device performance was found to be optimal when the solution concentration reached 10mg/mL.The highest Voc of the SnO2 planar perovskite solar cell can reach 1.151 V,indicating the Voc loss of the triple-cation perovskite was only 0.049 V.In addition,the water contact angle of the HTL treated by DMCA-TRZ was 63.7°,which was greater than 31.7°of untreated one,indicating the strong hydrophobicity of DMCA-TRZ,which significantly improved the humidity stability of the device.The interface modified devices can maintain 80%of the initial PCE after stored at 40%RH,25°C for over 900 h.3.The long-chain organic amine salt PBAI was used to passivate the surface defects of the perovskite film.Via adjusting the solution concentration of PBAI,the optimal value was obtained when the concentration reached 1 mg/mL.The efficiency of the device based on SnO2 was increased from 17.97%to 19.04.%,where Voc was increased from 1.064 V to 1.126 V.In addition,the humidity stability of the device after the interface treatment was significantly improved,which can maintain 90%of the initial efficiency after stored at 40%RH,25°C for over 900 h. |
