Passivate Leakage Current cia Active Layer and Electron Transport Layer Engineering for Enhanced Perovskite Optoelectronic Performance and Stability

<b>ABSTRACT BODY: </b><br/>Perovskite optoelectronic devices have garnered immense attention in recent years due to their exceptional efficiency, low-cost fabrication, and potential to revolutionize the field of photovoltaics. However, enhancing their stability and performance remains a critical challenge [1,2]. This study delves into the systematic investigation of perovskite optoelectronics, focusing on the pivotal role played by the active layer and electron transport layer (ETL) in determining device efficiency and stability [3]. We investigate the role of the electron transport layer (ETL) in enhancing the charge carrier transport and extraction processes. PDI-derivatives, such as PDIN, PDINO, and PDINN which are well-known and used material in organic optoelectronic devices’ electron transport layer, has high electron affinity, charge transport properties, and good chemical and thermal stability etc [4]. However, it was difficult to apply it on the perovskite layer because the alcohol-based solvent was used, so we solved this and applied it to the PSC device of the NIP structure It was confirmed that by applying PDINN on the PCBM layer, the defects of the PCBM layer were effectively passivated to reduce shunt leakage and at the same time suppress dark current. This process consequently suppresses the thermal degradation of the device and improves the stability of the device. Furthermore, we present a meticulous exploration of various active layer chemical physical process and their impact on the perovskite optoelectronic devices. Until now, it has been known that the grain size in the perovskite active layer is largely influenced by the time and temperature of the annealing process [5]. We note the relationship between the force and buoyancy acting on the active layer by the density of the washing solvent during the washing process, confirming that the lower density washing solvent receives lower buoyancy and consequently induces the formation of a larger grain size. It can be explained by the LaMer model, which represents the speed and time relationship between reaching the supersaturated state from the saturated state, confirming that the dark current is suppressed by reducing grain boundary concentration and passivate the leakage current through it [6]. This, in turn, leads to improved detection performance of the perovskite photodetector. Moreover, we have also conducted research to overcome the shortcomings of perovskite materials that are vulnerable to moisture [7]. A moisture trap capable of trapping water molecules is put into a perovskite solution to remove an infinitesimal amount of remaining moisture through over-night stirring, forming a well-oriented perovskite crystal, and preventing oxidation generated by internal moisture meeting the upper electrode when the device is driven, thereby improving device durability. In summary, our research offers valuable insights into the intricate interplay between the active layer composition, ETL properties, and the overall performance and stability of perovskite optoelectronic devices.<br/><br/>[1] Jang, W., Lee, J. M., Kim, B. G., Lim, J., Yang, Z., & Wang, D. H. (2023). Crystal Growth & Design, 23(9), 6916-6925.<br/>[2] Kim, B. G., Jang, W., Chun, J. Y., Lee, J., & Wang, D. H. (2022). Journal of Industrial and Engineering Chemistry, 116, 331-338.<br/>[3] Lee, J., Kim, B. G., & Wang, D. H. (2023). Solar RRL, 7(3), 2200937.<br/>[4] Yao, J., Qiu, B., Zhang, Z. G., Xue, L., Wang, R., Zhang, C., ... & Li, Y. (2020). 11(1), 2726.<br/>[5] Kim, H. D., Ohkita, H., Benten, H., & Ito, S. (2016). Advanced materials, 28(5), 917-922.<br/>[6] Whitehead, Christopher B., Saim Ozkar, and Richard G. Finke. Chemistry of Materials 31.18 (2019): 7116-7132.<br/>[7] Wang, Q., Chen, B., Liu, Y., Deng, Y., Bai, Y., Dong, Q., & Huang, J. (2017). Energy & Environmental Science, 10(2), 516-522.