| At present, production process of solar cell devices have faced several issues,for instance, heavy energy consumption in raw material preparing, p-n junction fabricating, complicated manufacturing technique and so on. It could overcomes the heavy energy consumption and complex device fabrication problems that preparing a narrow band gap semiconductor material with a good photoelectric property via a low temperature in-situ chemical route, then forming p-i-n junction by hybridizing with other matched semiconductors at low or room temperature, and then assembling solar cell devices. The highlighting of perovskite thin film solar cells devices has attract broad attention. In only 7 years, the PCE of perovskite thin film solar cells has exceed 20%. In atmosphere environment, perovskite CH3NH3PbI3 and CH3NH3PbBr3 thin films semiconductor materials were successfully fabricated in-situ at low temperature, and the growth mechanism of these materials has also been studied. The methods used for synthesizing perovskite thin films possess some good features, such as lower or none energy consumption, solvent recycling, non-toxic, green and environmental protection, which overcomes the shortcomings of high temperature, high vacuum, heavy energy consumption and complex reaction operation existing in traditional synthetic method, for example solution deposition, vapor deposition, vapor-assisted solution processing and spray coating. The optical and electrical characteristics of the perovskite semiconductor thin films materials have also been systematically studied. This study indicates that all of the as-synthesized compounds are p-type semiconductor with good photoelectric response. Transient photovoltaic(TPV) tests were conducted and show that these thin films have a long minority carrier lifetime as good as the perovskite thin films obtained via common two-step methods from the literature. Our research group design and assemable organic-inorganic hybrid thin film solar cells devices based on successfully synthesizing perovskite semiconductor thin films materials. Using small band gap semiconductor CH3NH3PbI3 and conjugate inorganic semiconductor ZnO, organic semiconductor spiro-OMeTAD as active layer materials, and CH3NH3PbI3 is the main absorber. Our research group has studied the factors that influence power conversion efficiency. Finally, power conversion efficiency(PCE) of 6.44% has been recorded from a perovskite thin film solar cell device with FTO/ZnO/ CH3NH3PbI3/spiro-OMeTAD/Au structure using absolute ethyl alcohol as solvent. We also have fabricated large area solar cell device samples(≧1.00 cm2) and have evaluated their photovoltaic performance under standard conditions(AM 1.5, 100 mW·cm-2), reaching 3.00%. On the basis of CH3NH3PbI3-based solar cell model, the semiconductor CH3NH3PbBr3 had been prepared and the influences on the morphology of various factors had been studied by the numbers. Power conversion efficiency of 0.5% has been recorded from a perovskite thin film solar cell device with FTO/ZnO/ CH3NH3PbBr3/spiro-OMeTAD/Au structure.Although there have been many studies that have developed perovskite solar cells during the past three years, our current work still exhibits the following novelties:(1) It is the first report using elemental Pb as a precursor to fabricate perovskite solar cells,which is a new kind of inorganic reactions;(2)All processes including perovskite thin films preparation and devices assembly were conducted in ambient atmosphere with controlling environment of relative humidity in the range of 40±3% and temperature in the range of 24±1℃, and the solar cells feature the high stability;(3) This Pb-initiated in-situ reaction allows for the fabrication of large area and uniform perovskite thin films. We will design and assemble various perovskite thin film solar cells based on Pb-initiated in-situ reaction in our future research. Optimizing the interface microstructure of device to increase the power conversion efficiency of these new type perovskite thin films solar cells. This research would play a positive role in promoting performance and theoretical study of perovskite solar cells. |
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