Investigation On The Fabrication,Encapsulation And Integration Of Low-Temperature Carbon Counter Electrode Based Perovskite Solar Cells

Solar energy,as one of the clean renewable energy,has given new hope to the growing energy crisis and environmental pollution facing mankind.The development of solar cell technology is an inevitable trend in the modern era.The emergence of the third-generation new concept solar cells,including dye sensitizers,quantum dots,organic thin films and perovskites solar cells,has brought new opportunities for the development of photovoltaic industry.In 2009,the organic-inorganic hybrid perovskite materials were first applied as photoreceptors in solar cells by Professor Miyasaka from the University of Tokyo in Japan.Just a few years later,photoelectric conversion efficiency of the perovskite solar cells has skyrocketed to 22.1%certified by the National Renewable Energy Laboratory in America,making it a promising substitute for traditional silicon solar cells.The breakthrough of carbon electrode perovskite solar cells,which simplifys the production process and reduces the preparation cost,further promotes the marketization of such devices.However,to realize the large-scale application of perovskite solar cells indeed,there are still many problems remain to be solved,such as poor stability,high production cost,large-area preparation,development of flexible devices and so on.In view of the problems above,this dissertation mainly focuses on the fabrication,encapsulation and integration of low-temperature carbon electrode perovskite solar cells.The specific research work is summarized as follows:（1）We proposed a kind of low-temperature conductive carbon paste that can be directly printed on the perovskite films and applied it into the preparation of carbon counter electrode for the hole-conductor-free perovskite solar cells.Performance of the devices was optimized by adjusting the composition of the carbon electrode.The devices also exhibited excellent stability.Our work laid the foundation for the development of low-cost,efficient and flexible perovskite solar cells.After that,by introducing CuPc as the hole transport layer,we proposed a fabrication method for the inorganic carbon electrode perovskite solar cell.Test results showed that the CuPc hole transport layer can effectively extract the photo-generated carriers and accelerate the hole diffusion process.Efficiency of the solar cell was enhanced by about 60%when compared with the hole-conductor-free device.The device still showed excellent stability under harsh environment with high temperature and high humidity,providing a novel idea for the development of stable perovskite solar cells.Furthermore,we also proposed a fabrication method for the planar-heterojunction perovskite solar cells by using TiO₂/SnO₂ bilayer as the photoanode.The results showed that the bilayer was better at extraction and transportation of the photo-electrons,which was more conducive to the improvement of cells’performance.The leakage current of the device was smaller,the depletion layer was wider,and the highest efficiency can reach 15.39%.Stability and repeatability of our devices were also very good,laying foundation for the development of highly efficient planar-heterojunction perovskite solar cells.（2）A packaging method based on PDMS was proposed to improve the stability and extend the lifespan of the perovskite devices.The PDMS film can effectively isolate moisture in air to prevent the deliquescence of perovskite active layer,greatly improving the device stability and ensuring the stable energy output.In addition,efficiency of the device was improved to some extent after packaging,owning to improved interface.After encapsulation,performance of the device didn’t show evident decay within a the test period of 3000 hours.SEM test was conducted to explore the interface changes before and after encapsulation.Furthermore,we introduced a series of testing methods including fluorescence spectroscopy,fluorescence confocal microscope,transient photocurrent,transient photo voltage and electrochemical impedance spectroscopy to investigate the relationship between the interface and the photon-generated carriers transport,revealing the mechanism of the enhanced device performance.（3）Device integration ideas to achieve multi-functionalization were proposed.On the one hand,a power pack with the integration of a perovskite cell and a supercapacitor based on a common carbon layer was proposed.When connected in parallel,energy generated by the perovskite solar cell can be stored in the supercapacitor part and then released as needed,realizing the unification of photoelectric conversion and energy storage.When connected in series,the device can provide an instantaneous enhanced output power by precharging the supercapacitor,broadening the application range of one single perovskite solar device.On the other hand,we proposed a novel photovoltaic-thermoelectric integrated device combining carbon electrode based perovskite solar cell with thermoelectric generator.During the photoelectric conversion process,the device can also utilize the heat loss caused by solar radiation at the same time.The available utilization of solar spectrum was broadened,and the overall conversion efficiencywasfurtherimprovedfrom9.88%（photovoltaic）to22.2%（photovoltaic-thermoelectric）.