Research On The Solar Cells In Novel Perovskite Materials

Organic-inorganic hybrid perovskites have emerged as extremely promising light harvesters for next-generation photovoltaic devices since 2009,owing to their great opto-electronic properties,including large absorption coefficient,high carrier mobility,desirable band gap,long charge carrier diffusion lengths and a low-cost solution fabrication process.Up to now,how to improve the stability become the main key issue in perovskite solar cells.Hence,we designed the experiments of optimizing the originally properties of perovskite material to improve the stability of perovskite solar cells,and carried out the following works:(1)We have demonstrated a new concept-two dimension/three dimension(2D/3D)perovskite hybrids(CA2PbI4/CH3NH3PbIxCl3-x)as light absorbers,achieving higher moisture stability compared with 3D perovskite solar cells.Cyclopropylammonium iodide(CAI)was spin-coated on the as-prepared 3D perovskite layer to form 2D/3D perovskite film in situ after annealing.As the storage time in the atmospheric humidity of 63 ± 5%increased,the 2D/3D perovskite hybrid film did not undergo any degradation after 40 days,device maintained 54%of the original efficiency after 220 hours.Whereas the 3D perovskite film decomposed completely under the same conditions after 8 days,the device lost all the efficiency within only 50 hours.(2)Doping 2-aminoethanesulphonamide monohydrochloride(ASCI)into the precursor solution of perovskite,which dramatic improving the hysteresis stability.ASCI facilitates the perovskite crystal arranging closely and results in excess PbI2 formed at the grain boundaries(GBs),ASCl and the excess PbI2 may passivate GBs.With the optimization of ASCI doping molar ration of 5%,the average PCE deviation AR between conventional reverse and forward voltage scanning of perovskite decreased from 3.43%to 0.26%(the smallest AR is 0.01%),which almostly cancealed the photocurrent hysteresis.