Study On The High Efficient And Steady Perovskites Solar Cells Fabricated In Ambient Air Conditions

The perovskite solar cell is a new star in the energy industry in recent years,which has attracted many researchers to fight for it.In 2009,Japanese scientists used perovskite materials for the first time in dye sensitized solar cells,and got the efficiency of 3.8%,which was rated as the world's top ten scientific and technological breakthrough in 2013 by Science.In 2018,the perovskite solar cell made by Switzerland EPFL measured 23.25%of photoelectric conversion efficiency,which is the highest efficiency certified so far.Although the efficiency of perovskite solar energy continues to increase,its poor stability has been criticized by people.At present,the preparation of most high-efficiency perovskite solar cells needs to be carried out in a special environment that blocks moisture and oxygen.Therefore,the development of large-scale production and the application of industrialization is slow.In order to achieve large-scale application of industrial and people's livelihood as soon as possible,this article aims to improve the photoelectric conversion efficiency of perovskite solar cells and the stability in the air from the aspects of improved preparation methods,introduction of trace additives,etc.The main research contents and conclusions are as follows:1?A special additive of n-butyl amine is used to prepare full coverage and continuous PbI₂ films,and then a low-hydrophilic n-butanol solvent and a novel multi-cycle short-time dipping reaction are used to successfully convert these PbI₂films into high-quality perovskite films with smooth surface and large crystal grains similar as that of the ones prepared with one-step anti-solvent method in glove box.The best performance device based on the high-quality perovskite film achieves an average power conversion efficiency?average of the forward and reverse scans?of17.56%with slight hysterisis and good reproducibility.2?We report a facile CH₃NH₃Br?MABr?additive route to enhance the open circuit voltage,in order to achieve both high power conversion efficiency and good long-term stability.We demonstrate that the application of MABr additive can greatly improve the quality of the perovskite film by diminishing the number of small crystal grains to form large ones,which can substantially decrease grain boundaries and enable direct connection of electron-and hole-transport layers with one large crystal grain.These changes lead to enhanced electron transport rate,suppressed recombination,improved photovoltaic performance,and reduced hysteresis of the device assembled using the perovskite film with MABr additive compared to the device without the MABr additive.Furthermore,the large crystal grains and their compact stacking can effectively withstand moisture corrosion,thereby contributing to significantly enhanced air stability for the perovskite film with MABr additive and the corresponding device.This work highlights the valuable MABr additive route for developing potentially available,efficient and stable PSCs.3?In order to realize the preparation of formamidine-based perovskite solar cells in ambient air conditions,we added the polyvinyl butyral?PVB?and polyvinyl alcohol?PVA?to the precursor liquid to increase its moisture resistance.Furthermore,PVB and PVA are used as additive for enhancing the quality of the perovskite films.Especially,the perovskite film with PVB additive shows clearer improved quality because of the formation of larger crystal grains which can go from bottom to top and smoother surface than that of the one with PVA additive.The higher quality of the perovskite film with PVB additive can not only achieve better carrier transport dynamics,improved photovoltaic performance,reduced hysteresis,but also the greatly improved air stability because of the formation of larger crystal grains and more compact stacking of these crystal grains for effectively blocking the moisture corrosion.This work demonstrates the valuable PVB additive route for developing potentially available efficient and stable PSCs.