Spectral Control,Interfacial Modification And Photovoltaic Performance Of Perovskite Absorption Layer

In recent years,the certification efficiency of perovskite solar cells(PSCs)has reached up to 22.7%,closing to the efficiency of crystalline silicon solar cells.However,the issues concerning only visible spectral absorption,and limited charge transfer incomplicated interface between multifunctional layersneed to be settled.For the purpose of improvement the photoelectric performance of PSCs,two strategies concerning spectral control and interfacial modification are involved in this thesis.Firstly,IR806-UCNCs embedded perovskite light absorption layer is used to broaden the spectral absorption range of the PSCs,and the second work is to improve the charge transport properties of the QDs films by constructing a high-speed charge transport network of CNTs and surface-modified PMMA layer in perovskite QDs light absorption layers.The specific research content is as follows:(1)This work reports a viable strategy of incorporating IR806 dye-sensitized upconversion nanocrystals(IR806-UCNCs)into planar PSC for broadband upconversion of NIR light(800-1000 nm)into perovskite absorber-responsive visible emissions.A smart trick is adopted to prepare hydrophilic IR806-UCNCs via a NOBF4 assisted two-step ligand-exchange that allows incorporating with perovskite precursor for growth of IR806-UCNCs-incorporated planar perovskite film.Such IR806-UCNCs-incorporated planar perovskite film enables to harvest NIR light in a range of 800-1000 nm and simultaneously transfer the captured energy to the Yb3+/Er3+ ions to generate strong upconversion emission that can be absorbed by the perovskite.The IR806-UCNCs-incorporated cell exhibits a power conversion efficiency of 17.49%,corresponding to 29%increment from that of the pristine cell(13.52%)under AM 1.5G and an impressively high NIR-PCE of 0.382%under NIR irradiation(?>780 nm)are achieved.(2)?-CsPbI3 QDs are prepared by thermal injection method.In order to improve the charge transport properties of the QDs films,a high-speed charge transport network of CNTs and PMMA layer were introduced to modify the interface between ETL/perovskite QDs/HTL.The PMMA layer reduces the carrier recombination due to decreased pinholes and surface trap states of perovskite QDs layer and simultaneously provides an insulation layer to prevent degradation of perovskite QDs layer.The CNTs conductive network improves the conductivity,extraction efficiency of the photogenerated chargeand.Both of these interface modifications inhibit the electron-hole recombination,finally leading to a great improvement in Jsc and FF.The PCE of 7.27%is obtained by the CNTs-PMMA modified cell.The stability of CNTs-PMMA modified cell exhibits excellent air stability also improved,with the PCE of 83%of the highest efficiency after 36 days.