Study On Doping Of Metal Elements In Perovskite Solar Cells And New Lightabsorbing Materials

The perovskite solar cells have become a hot topic due to their simple preparation process,low cost and high conversion efficiency,and provides an effective way to solve the energy problem.However,the toxicity of lead in the traditional perovskite material CH₃NH₃PbI₃,and its instability in response to light,temperature and humidity limit the commercialization of this technology.Therefore,solving the above problems has become the key to the commercial application of solar cells.In this paper,we mainly explore the toxicity and stability of lead in MAPbI₃.We tried to replace the toxic element lead with calcium and completely abandon traditional perovskite materials,a new lead-free material AgBiI₄ that is used as the light-absorbing layer of solar cells to prepare solar cells with high efficiency,stability and environmental friendliness.The main content is as follows:1.The organic-inorganic perovskite material with better energy alignment in the solar cell device will have a profound impact on the solar cell performance.It is valuable to tune the energy states by element substitution and doping in perovskites.Here,we present that Ca²⁺is incorporated into CH₃NH₃PbI₃,which up-shifts the valence band maximum and the conduction band minimum,leading to a difference between the band gap and the Fermi level in the device.Consequently,Ca²⁺incorporation results in an enhancement of the photovoltage and photocurrent,achieving a summit efficiency of 18.3%under standard 1 sun?AM 1.5?.This work reveals the doped perovskite to improve the solar cell performance by tuning the energy state.2.Organic-inorganic hybrid lead halide perovskites have recently realized significant development.However,the toxicity of lead?Pb?and the poor stability might eventually hamper the commercialization of perovskite solar cells?PSCs?.Here,we present an environment friendly and stable all inorganic rudorffite AgBiI₄ as solar absorber by solution-based synthesis of thin-films.AgBiI₄ films fabricated by 0.6 M solution and annealed at 150°C show dense grains and high surface coverage.Furthermore,the AgBiI₄ films exhibit greater thermal stability and photostability than CH₃NH₃PbI₃.Ultimately,PTAA was selected as the hole transport material to compare the effects of PTAA and P3HT on the device performance and achieve a power conversion efficiency?PCE?of 2.1%under standard 1 sun?AM 1.5?.The devices also show excellent long-term air stability and still maintain 96%of its initial PCE even after 1000 h at relative humidity of 26%.This work highlights new directions for further exploration of Pb-free and stable solar cells.