| Since 2009,the perovskite solar cells were first reported that the photoelectric conversion efficiency was 3.8%.By the end of 2015,that efficiency was nearly 22.1%.Because of its high efficiency,easy produce and low cost,the new cells and excellent stability,PSC have attracted more and more attentions.The researchers find that structure and properties have a significant effect on the photovoltaic performance.The mesoporous layer act as a perovskite skeleton adsorption and absorb and transmilate electron Therefore,the structure and morphology of mesoporous layer not only affect the morphology of the perovskite layer determines but also determine the electron diffusion coefficient and electrical life.The main research contents are as follows:(1)The TiO2 NRAs were grown on FTO substrates with TiO2 seed layer via hydrothermal process,then CH3NH3PbI3 was deposited on the TiO2 NRAs by one-step spin coating,last,commercial carbon ink was using as a counter electrode by doctor blading.FE-SEM,XRD,UV-Vis spectrophotometer,electrochemical workstation were used to analysis the arrays.In the synthesis process,the different lengths of TiO2 NRAs were obtained through different reaction times.The uniformity TiO2 NRAs were grown on the FTO under the optimal reaction conditions.According to the X-ray diffraction pattern,the arrays were rutile and grown along(101).The arrays were distributed,and the rod diameter was about 30 nm,height of the arrays increased with the reaction time by SEM.When the time was 50?90 min,the length was from 192 nm to 1234 nm.UV-Vis showed that the light absorbance by perovskite was related to the length of the TiO2 NRAs.The perovskite had the largest light absorbance,while the length was 688 nm.The cell achieved the best performance with the PCE was 8.56%,Jsc was 19.93 mA/cm2,Voc was 895 mV,FF was 48%,while the thickness of TiO2 NRAs were 688 nm.Experimental results shown that the optical thicknesses of the anode directly affect the performance of photovoltaic cells,when the thickness of the nanorod array was 688 nm,the battery got the best optical and electrical properties.(2)The ZnO NRAs were grown on FTO substrates with ZnO seed layer via hydrothermal process,then CH3NH3PbI3 was deposited on the TiO2 NRAs by one-step spin coating,last,commercial carbon ink was using as a counter electrode by doctor blading.FE-SEM,XRD,UV-Vis spectrophotometer,electrochemical workstation was were used to analysis the arrays.The ZnO NRAs were grown on FTO substrates via hydrothermal process.In the synthesis process,the different lengths of ZnO NRAs were obtained through different reaction times.ZnO NRAs were wurtzite according to the XRD.By SEM image,ZnO NRAs distributed by the sparse state slowly became homogeneous state with the reaction time.The reaction time was 180 min?240 min,while the length was 100 nm to 700nm.When the ZnO NRAs length was 454 nm,the perovskite had the largest light absorbance.PSC got the highest efficiency was 6.1%,Jsc was 14.24 mA/cm2,Voc was 945 mV,FF was 0.46 under the same length.It shown that,under this length,the perovskite had the maximum adsorption amount,the photo-generated electrons got the most,the cells had the best efficiency.(3)The TiO2 boxes and flowers like TiO2 were synthesized via hydrothermal method.The field emission scanning electron microscopy,electrochemical workstation were used to analysis the microstructural characterizations and photoelectric properties.Finally,the TiO2-box got the highest PCE 4.15%,because of its small size,big surface to absorb more CH3NH3PbI3. |
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