| The organic-inorganic hybrid perovskite solar cells have attracted great amount of research due to its excellent optoelectronic properties.Its champion power conversion efficiencies(PCEs)is over 25%which is comparable with the best silicon solar cells.In this respect,inorganic CsPbI3 perovskite solar cells have wide application prospect and tremendous potential for commercialization,ascribed to their suitable and adjustable bandgap,high charge carrier migration rate,glorious thermostability and easy fabrication.However,there are still many problems about inorganic perovskite solar cells,including their low PCEs compared with hybrid organic-inorganic perovskite solar cells,notorious stability in ambient moisture.Therefore,there are still many improvements and further study containing the way to fabricate the devices in open environment and stability of device in high relative humidity.In order to solve the above-mentioned disadvantages about inorganic perovskite solar cells performance and stability,we develop some methods and research to optimize the device in regard with adjusting the perovskite precursors,fabrication technology:1.In order to develop the CsPbI3 perovskite solar cells ability to utilize the solar spectrum efficiently and enhance the sunlight harvest,we doped the up-conversion nanoparticles into the PTAA hole transport layer to reinforce the device photoelectric ability.When the inorganic CsPbI3 perovskite solar cells are modified with up-conversion nanoparticles,the regenerative visible spectrum can be absorbed by perovskite absorption layer where up-conversion nanoparticles can absorb the NIR photons and convert them into visible light.In addition to the negligible up-conversion effect,we find that modified hole transport layer will change its refractive index and result in strengthening the light absorption ability.At the same time,up-conversion nanoparticles can serve as scattering centers,which is beneficial to extend the sunlight optical path by combining with scattering and reflecting sunlight,leading to producing more photoelectric current.The champion short circuit current density and the PCE of final optimized device can reach up to 19.17 mA/cm2 and 15.86%.This method will provide a new optical management strategy applying to inorganic CsPbI3 perovskite solar cells.2.In view of the CsPbI3 perovskite solar cells notoriously sensitive to the ambient moisture,the manufacturing process will increase the cost and restrict the operation conditions.Based on these shortcomings,we successfully developed an easy one-step anti-solvent hot substrate spinning-coating method to fabricate inorganic CsPbI3 perovskite solar cells.Pre-heating substrate and methyl acetate antisolvents will facilitate the film crystallization in the open air.High temperature and antisolvents will accelerate the precursor concentrations up to the supersaturation limit,and induce the perovskite heterogeneous nucleation at the same time.In the open environment,the champion PCE of the inorganic CsPbI3 perovskite solar cell was up to 15.91%.This study will contribute to the development of manufacture processes for CsPbI3 film in an ambient atmosphere and promote the commercialization of inorganic perovskite solar cells.3.We develop the device optoelectronic property and enhance the CsPbI3 film stability,by adjusting CsPbI3 perovskite precursor components and passivating the perovskite film surface and grain boundary.When the precursor components were regulated,we can obtain high quality CsPbI3 film which is a compact,uniform and pinhole-free surface morphology.In addition,when the film surface was passivated with organic molecules,the CsPbI3 film will have fewer defects and nonradiative recombination centers,which will reinforce the carriers transport and enhance the PCE of device.After optimizing the device,inorganic CsPbI3 perovskite solar cells can achieve a champion PCE up to 16.78%and the stability of the device can also build up without encapsulation in the open air.We provide a reasonable method to increase the PCE of device and strengthen the device stability by combining the components of regulation and surface passivation. |
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