Interface Control And Study On Photoelectric Performance Of Perovskite Solar Cells

Organic-inorganic hybrid perovskite materials have attracted widely attention due to their advantages such as high light absorption coefficient,high carrier mobility,simple preparation process,and low cost.In recent years,solar cells based on perovskite materials have developed rapidly with the highest photoelectric conversion efficiency reached 25%.However,the interface between the layers in perovskite solar cells and the grain boundaries in the perovskite film increase the carrier transport resistance,thus leading to the increased probability of carrier recombination,which seriously affects the optoelectronic performance of devices.Therefore,this paper focuses on interface regulation,aiming at optimizing the carrier transport process in perovskite solar cells.The influence of interface regulation on the performance of perovskite solar cells is systematically analyzed and discussed.The main research contents and conclusions are as follows:?1?Ti₃C₂ nanosheets with good conductivity and optoelectronic properties were selected as additives to composite with TiO₂ to prepare the Ti₃C₂/TiO₂ composite electron transport layer.Compared to the pure TiO₂ electron transport layer,the conductivity and electron mobility of Ti₃C₂/TiO₂ electron transport layer are increased by an order of magnitude,which boost the electron extraction and transmission.Therefore,the carrier recombination probability and the hysteresis of the device are reduced,accompanied with the increased photocurrent.The photoelectric conversion efficiency of the device is increased from the original 11.8%to 14.3%.?2?To passivate defects in the perovskite film,Ti₃C₂ quantum dots with good conductivity and optoelectronic properties were added into the perovskite film,which can help accelerate the carrier transport process and reduce non-radiative carrier recombination.The results show that the addition of Ti₃C₂ quantum dots increases the crystallinity of perovskite,thus effectively reducing the density of defect states in the perovskite film.Therefore,the photocurrent and open circuit voltage of the device significantly increase.The photoelectric conversion efficiency reaches 16%,which is33.3%higher than that of the original device.?3?In order to speed up the extraction rate of holes,the interface of the hole transport layer/perovskite layer was modified with hybrid CdSe/CsPbI₃ quantum dots which possess matched energy levels with that of perovskite and Spiro-OMeTAD.The results show that a stepped band structure is formed between the hybrid CdSe/CsPbI₃ quantum dots and perovskite,which promotes the extraction of holes and reduces the accumulation of charges at the interface,thus increasing the open circuit voltage of the device and weakening the hysteresis of device.Benefit from the inherently superior optical properties of quantum dots,the photocurrent of the device has also been improved,and the photoelectric conversion efficiency of perovskite solar cells achieved 17.1%.In addition,the introduction of hybrid CdSe/CsPbI₃quantum dots also enhances the hydrophobicity of the perovskite film and greatly improves the stability of the device.