Performance Research Of Perovskite Solar Cell With Light Conversion Transport Layer Utilizing Prism Scattered Light

Over the past decade,organic-inorganic halide perovskite solar cells(PSCs)attracted a large number of researchers.And their power conversion efficiency(PCE)has been significantly enhanced from 3.8%in 2009 to 25.7%in 2021.The most commonly used light-absorbing material is heterogeneous lead halide perovskite(CH₃NH₃PbI₃(MAPbI₃))which has a good direct band-gap(1.55 e V).And the MAPbI₃ has high carrier mobility and high light absorption coefficient.Although MAPbI₃ has good photoelectric properties,it can only respond well to the visible lights from sunlight,not to infrared and ultraviolet lights,which account for more than half of the solar spectrum.The low-energy infrared lights are not enough to excite the MAPbI₃,and that the high-energy ultraviolet lights cause energy wastage,even a certain photo corrosive effect on MAPbI₃ surface.Therefore,the utilization of infrared and ultraviolet lights in sunlight should be a considerable way to enhance the PCE of PSCs.For the utilization of near-infrared lights,some up-conversion luminescent materials can be used to obtain the visible lights through the absorption and conversion of multiple near-infrared photons.For the utilization of ultraviolet lights,some down-conversion luminescent materials can be used to absorb one high-energy photon and convert to multiple low-energy photons.The introduction of down-conversion luminescence materials in PSCs can convert ultraviolet lights into visible lights,which increases the utilization ratio of incident sunlight.Therefore,the selection and use of up-conversion and down-conversion luminescent materials with excellent performance may greatly enhance the PCE of solar cells.Because the sunlight is a kind of compound light,in the process of light conversion,the simultaneous use of two conversion luminescent materials will inevitably disturb the light transmission,thus reducing the utilization efficiency of sunlight.And the spectral splitting techniques can precisely disperse the sunlight.The incident compound light is divided into monochromatic lights with different wavelengths through the beam splitter,and then these monochromatic lights illuminate the matching absorption materials in solar cell.Apparently,these spectral splitting techniques can effectively split the sunlight to achieve the purpose of separately using different wavelengths of sunlight.In our study,the TiO₂ films doped with Er³⁺and Yb³⁺were synthesized by sol-gel method and the ratio of Er³⁺and Yb³⁺ions was optimized to obtain the highly effective up-conversion and down-conversion luminescent materials.The organic-inorganic halide perovskite CH₃NH₃PbI₃ solar cell was chosen as the research object,in which the carbon electrodes was used and the hole transport layer was not used.The TiO₂ electron transport layer is divided into three parts,namely,the up-conversion part,the un-doped part and the down-conversion part,which correspond to the infrared,visible and ultraviolet lights from the split solar spectrum by a prism,respectively.The low-energy infrared lights are converted into visible lights by the up-conversion part and the high-energy ultraviolet lights are converted into visible lights by the down-conversion part.All obtained visible lights can be effectively absorbed by the perovskite CH₃NH₃PbI₃ absorption layer.Compared with the solar cells that do not utilize a prism,the solar cells combined with the light conversion luminescent materials and prism have significantly enhanced the utilization efficiency of sunlight.It can be predicted that this work provides a new method for the full-spectrum utilization of solar cells.