Project Details
Projekt
Compositional and electronic inhomogeneities in printed non-fullerene solar cells and their effect on device performance and stability
Applicant
Professorin Dr. Yana Vaynzof
Subject Area
Experimental Condensed Matter Physics
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 461909888
Printed organic photovoltaics offer the possibility to produce inexpensive, large area and flexible products, yet certain challenges still need to be addressed prior to its integration in industrial applications. One of these challenges is related to the difficulty of forming uniform, homogeneous films over large areas. The presence of inhomogeneities will affect the function and performance of the printed devices as well as its stability. In this project, we will investigate the formation of compositional and electronic inhomogeneities in printed organic solar cells by spatially and energetically resolved photoemission spectroscopy (PES). Spatially resolved information across large areas can be obtained by using PES imaging or PES mapping, offering a resolution of 1 and 100 um, respectively. These length scales are highly relevant to the study of inhomogeneities and make it possible to characterise large samples (on a cm length scale). Vertically resolved measurements with a resolution of 1–2 nm are made possible by coupling the spectroscopic characterisation with gentle etching by a gas cluster ion beam, which offers an essentially damage-free etching of organic materials. The two methods can be combined in order to track the evolution of the composition and electronic structure of materials across large areas at various depths of the device active layer. These methods will enable us to characterise both compositional and electronic inhomogeneities as a function of lateral dimensions and depth. Together with other partners of the Research Unit POPULAR we will reveal how these inhomogeneities impact on the device performance, and in particular on the stability. The latter will be examined in detail in this project in order to elucidate how the presence of inhomogeneities formed during fabrication can lead to degradation, and alternatively, how the ageing of homogeneous printed layers can lead to the formation of inhomogeneities.
DFG Programme
Research Units
