(Invited) Understanding the Energy Band Alignment in Inverted Organic Thin-Film Photovoltaic Devices

Abstract

The energy band alignment in thin-film and low-dimensional devices is extremely important. However, experimental determination or theoretical prediction of the energy level alignment has been difficult to realize, especially under typical operating conditions. Following a recent breakthrough in our group, where SKPM technique was employed to image the vacuum level profile across the depth direction of an operando organic PV device with a conventional stacking structure, here we present the vacuum level alignment measurement on an inverted structure OPV device. Previously, there had been conflicting reports on the built-in field and the device operation polarity. In this talk, we will present a comprehensive understanding of the energy level alignment in inverted structure OPVs, and how the measured parameters can be adopted in numerical modeling of the device physics.