Organic-inorganic hybrid halide perovskite solar cells have become a research hotspot in the photovoltaic field due to their excellent photoelectric properties,low preparation costs,and high conversion efficiency.As the core layer of perovskite devices,the electron transport layer mainly plays a role in extracting and transporting photogenerated charge carriers,and can serve as a hole blocking layer to suppress charge recombination in the perovskite active layer.Therefore,excellent performance of the electron transport layer is crucial for developing perovskite solar cells.However,the rigid electron transport layer(mesoporous or compact layer)commonly used in perovskite photovoltaic devices currently requires high-temperature sintering,which limits its application in flexible perovskite devices.Therefore,developing a flexible electron transport layer that can be applied in the field of perovskite photovoltaics has become an urgent problem to solve.Nano ZnO has suitable energy levels and high electron mobility and can be prepared at low temperatures,widely used as an electron transport layer in photovoltaic devices.Therefore,this work prepared rigid and flexible nano ZnO electron transport layers using spin coating and electrospinning methods,respectively,and determined the optimal preparation process for flexible nano ZnO using the electrospinning method.The effects of rigid and flexible nano ZnO on perovskite thin films'morphology,structure,and spectral properties were systematically studied by scanning electron microscopy,X-ray diffraction,UV-Vis absorption spectroscopy,and steady-state/transient fluorescence spectroscopy.The results indicate that the morphology of perovskite films strongly depends on the morphology of substrate nano ZnO.The perovskite thin films based on rigid and flexible nano ZnO exhibit almost the same structure and spectral absorption range(400～800 nm),with fluorescence emission peaks around 770 nm.The fluorescence quenching efficiency of flexible nano ZnO is 82％,almost comparable to that of rigid nano ZnO(85％).Furthermore,based on transient fluorescence kinetics data,the interfacial charge separation efficiencies of rigid and flexible nano ZnO were calculated to be 61％and 41％,respectively.It indicates that the flexible nano ZnO prepared by electrospinning has certain interfacial charge separation capabilities and is expected to become a new type of flexible electron transport layer.It provides an important reference value for designing flexible substrate perovskite solar cells and has practical significance for promoting perovskite photovoltaic applications.
维普
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