Research group of song Yanlin, Institute of chemistry, Chinese Academy of Sciences and research group of Xing Guichuan, Professor of Macau University: preparation of large-area two-dimensional three-dimensional perovskite solar cells

Lead two-dimensional perovskite has been widely used in the field of solar cells due to its high environmental stability and high efficiency in inhibiting ion mobility However, the two-dimensional perovskite under natural conditions is composed of quasi two-dimensional perovskite with different n-values, which results in different quantum confinement and greatly limits the transmission of photocarriers Recently, the research group of song Yanlin, Institute of chemistry, Chinese Academy of Sciences, and Professor Xing Guichuan, University of Macau, have combined the pure two-dimensional perovskite (edbepbi4) with three-dimensional perovskite, which has effectively overcome the multi-dimensional quantum well confinement, greatly improved the carrier transport performance, and successfully applied to two-dimensional quantum well- A large area solar cell with three-dimensional transverse heterojunction has obtained a highly efficient and stable modular module Relevant results were published in Adv Mater (DOI: 10.1002/adma.201805323) The first author of this work is Li Pengwei, a doctoral student in the Institute of chemistry, Chinese Academy of Sciences Brief introduction of research group of song Yanlin research group is mainly engaged in the research of organic photoelectric information functional materials, polymer photonic crystals and nano green printing materials and technologies The research group has published more than 300 papers in the academic journals of NAT Commun., SCI Adv., J am Chem SOC., adv mater., angelw Chem Int ed., adv energy mater., adv funct Mater., small, nano energy, etc Leading edge scientific research achievements of researcher song Yanlin: since 2018, the efficiency of 3D perovskite solar cells has exceeded 23%, which can be compared with crystalline silicon solar cells However, the stability of the battery is still facing a huge test Two dimensional perovskite provides an opportunity for the application of perovskite solar cells due to its high chemical stability Due to the existence of long-chain complexes, two-dimensional perovskite under natural conditions has formed a quasi two-dimensional phase separation structure with multi-dimensional quantum well effect, which restricts the transmission of photogenerated carriers Therefore, the efficiency of solar cells with two-dimensional perovskite as light absorbing layer is far lower than that of three-dimensional perovskite Therefore, overcoming the contradiction between high efficiency and high stability is the only way to realize the industrial application of perovskite battery Recently, the research group of song Yanlin, Institute of chemistry, Chinese Academy of Sciences, and Professor Xing Guichuan, University of Macau, have worked together to adopt the method of two-dimensional perovskite microcrystals mixed into three-dimensional perovskite, overcome the multi-dimensional quantum well confinement of two-dimensional perovskite, and successfully obtained the pure two-dimensional three-dimensional perovskite transverse heterojunction Because the two-dimensional perovskite used in this experiment has a diamine (2,2 - (ethylenedioxy) bis (ethyllammonium)) structure, the diamine molecules exposed outside the crystal interact with the organic cation Ma + in the three-dimensional perovskite, making the two-dimensional perovskite effectively inlaid in the three-dimensional perovskite grain boundary At the same time, this interaction can slow down the crystallization of perovskite and make it easy to obtain perovskite with large grain size (Fig 1) Figure 1 Characterization of the effect of pure two-dimensional perovskite microcrystals on the properties of three-dimensional perovskite (source: adv mater.) by transient absorption spectroscopy It is found that this kind of two-dimensional perovskite and three-dimensional perovskite will not form a quasi two-dimensional multi-dimensional quantum well structure through van der Waals force, which can effectively avoid the adverse effect of carrier in the transmission process due to quantum confinement The calculated results show that the lifetime of photo generated carriers in the two-dimensional and three-dimensional perovskite films is increased by four times, and the diffusion length is increased by three times (Fig 2) Figure 2 Calculation of transient absorption, carrier lifetime and diffusion length of different films (source: adv mater.) at the same time, the density of state of hole trap measured by space charge limited current method is reduced from 6.2 ± 0.5 × 1015 cm - 3 to 2.8 ± 0.3 × 1014 cm - 3, and the density of state of electron trap is reduced from 4.4 ± 0.5 × 1015 cm - 3 to 2.9 ± 0.3 × 1014 cm - 3- 3 Therefore, the mobility of carriers in the two-dimensional and three-dimensional perovskite films is increased by 10 times It is also found that the perovskite film has a uniform surface potential, which also provides favorable conditions for further separation of carriers at the interface (Fig 3) Figure 3 Measurement of defect density of state and surface potential (source: adv mater.) the efficiency of solar cell prepared by this two-dimensional to three-dimensional perovskite film is as high as 21.06%, and the photoelectric conversion efficiency of large area (342cm 2) perovskite device prepared by printing technology is 11.59% After 3000 hours of aging under natural conditions, the efficiency loss of the modular solar cell is less than 10%; it also shows strong stability under 500 hours of continuous light, without significant attenuation (Figure 4) Figure 4 Review of previous reports on the photoelectric performance and stability of devices (source: adv mater.): Song Yanlin research group, Institute of chemistry, Chinese Academy of Sciences: a series of important research progress in the field of nanomaterial printing and patterning Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeangoapp, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.