Soonil Hong1,Eun Young Park1,Sooncheol Kwon2,Nam Joong Jeon1
Korea Research Institute of Chemical Technology1,Dongguk University2
Soonil Hong1,Eun Young Park1,Sooncheol Kwon2,Nam Joong Jeon1
Korea Research Institute of Chemical Technology1,Dongguk University2
The formation of well-connected metal-oxygen gel networks in ‘sol-gel’ processed transition metal oxide (TMO) interlayer on top of the entire photoactive layer has long been a research goal to ensure large-area PSC modules with high performance and long-term stability; however, it has not yet been achieved because very little is known about the actual nanomorphology from atomic-scale reactions of TMO precursors and its impact on device characteristics. Here, we report for the first time a direct observation of continuous metal-oxygen network in ‘sol-gel’ processed metal oxide film on top of favorable photoactive layer, which can be used as an ideal inner encapsulation layer for achieving large-area organic and perovskite modules with long-term stability. By employing a high-resolution Auger electron spectroscopy, which provide an advantage of short data acquisition times and thus an improved surface sensitivity and accuracy, we successfully obtain the lateral and vertical distribution of chemical components throughout the entire metal oxide thin film surface, indicating that a low surface energy difference at the organic/metal oxide interface allows long-range diffusion of metal ion precursors to promote continuous chemical synthesis associated with oxo-bridge formation. The features of resultant continuous metal-oxygen network can prevent the permeation of surrounding moisture and oxygen into the photoactive layer, resulting in PSC modules with long-term stability, approaching an efficiency of 14.5% and maintaining over 80% of their initial efficiency until 2000 hours with an area of 9.06 cm2, respectively.