| The perovskite solar cell(PSC)has received extensive attention in recent years with the rapid growth of photoelectric conversion efficiency(PCE).The organic-Inorganic hybrid perovskites exhibit excellent photoelectric characteristics,such as the adjustable direct band gap,high optical absorption factor,long carrier diffusion length and so on.The PCE of PSC has increased over 22%.Not only in the photovoltaic field,the perovskite has the potential to be applied in light emitting diodes,detectors,lasers and amplifiers.Although perovskite has the superior photoelectric properties,the existence of intrinsic defects will restrict the performance of the device.Except for the intrinsic defects,the defects between layers in solar cell also can affect the performance.In this article,we focus on the above issues of PSCs to improve the performance and stability based on the p-i-n type PSCs,which have lower hysteresis,more convenient preparation and better stability.Firstly,the crystallization of perovskite films is enhanced by using the quantum dots as the nucleation centers in the anti-solvent.Then,we prepared the 1D perovskite nanowire network on the surface of the polycrystalline perovskite film after the modification of short alkyl amine(BA,n-butyl anime).The presence of BA can passivate the surface defects,and the presence of nanowires can help accelerate the extraction of carrier.Finally,the low-temperature prepared PTAA(Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine])is applied to obtain the improved stability of the PSCs instead of high temperature prepared NiO.The PTAA is modified by PFN and PEI can enhance the perovskite film compaction and reduce the interface trap-state density,which lead to an improved performance.The results obtained are as follows:(1)Based on the configuration of FTO/NiO/CH3NH3PbI3/PCBM/Ag,we have successfully prepared the CH3NH3PbBr3 quantum dots(QDs)at room temperature.The CH3NH3PbI3 perovskite film prepared by solution-processed anti-solvent method using QDs as heteroepitaxy nucleation centers can enhance the crystallinity of the film and decrease the grain size.Then the optimized film is applied for the preparation of the device:FTO/NiO/perovskite-QDs/PCBM/Ag.This type of device as a light-emitting diode has achieved higher luminous efficiency;As a solar cell,the efficiency of the PSC increased from 14.49%to 17.1%,and explained that the crystallinity of the thin film grain has more influence on the performance of the device than grain boundary.(2)Based on the configuration of FTO/NiO/CH3NH3PbI3/PCBM/Ag,we reported a simple method for the preparation of the in-situ perovskite nanowire network by spin-coating the BA on the polycrystalline perovskite film.The analysis of Fourier infrared demonstrates the interaction between BA and perovskite.The PL intensity of the modified perovskite is increased by more than 4 times,and the fast decay of the perovskite/PCBM interface decreased from 1.11 ns to 0.97 ns.BA can passivate the surface defects of perovskite film,and the nanowires can promote carrier transmission.The performance of the inverted PSCs based on NiO was improved from 14.32%to 16.66%,with enhanced stability.(3)Based on the configuration of FTO/PTAA/Cs0.05FA0.81MA0.14Pbl2.55Br0.45/PCBM/Ag,we fabricated the inverted planar PSCs with low temperature prepared PTAA and more stable Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite.Then the introduction of PFN {Poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]} and PEI(polyethyleneimine)in PTAA have greatly improved the hydrophobicity of PTAA surface and enhanced the film quality of the perovskite.After modified by PFN and PEI,the PCE increased from 14.26%to 15.89%and 15.87%respectively,and compared with all the inverted structure devices,the devices based on PTAA show better air stability and light stability. |
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