Electrically detected electron spin resonance of doped-phthalocyanine/C60 heterojunction

Mechanisms of spin-dependent dark conductivity in films of a soluble fullerene derivative under bipolar injection

“…The idea is to observe how the spin-degree of freedom controls current by manipulating spins by magnetic resonance and to then observe how this induced spin change modulates the electrical current. EDMR has been applied to various organic materials and device systems in the past [4][5][6][7][8][9][11][12][13][14][15][25][26][27]. For this study, we have conducted pulsed (p) EDMR experiments, where the transient of the current change from the steady state is measured after a very short but powerful coherent spin manipulation is performed [28,29].…”

“…As fullerenes have attracted much interest due to their excellent applicability as electron acceptors in organic solar cells [1,2], significant research efforts have focused in the past on how the electron spin degree of freedom can influence the performance of these devices [3,4]. Most studies of spin-selection rules have therefore been centered around transitions of photogenerated charge carriers [5][6][7][8] while electronic processes in the dark have received comparatively little attention and only for blend systems [4]. Recently, we reported that pronounced spin-dependent transitions can also exist in the dark current of fullerene films [9].…”

“…With the study presented in the following, we aim to provide a more comprehensive picture of this phenomenon. We have investigated spin-dependent transitions under dark conditions in a widely used fullerene derivate, [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM). We address the following questions: What is the physical nature of spin-dependent electronic charge carrier transitions that control the macroscopic conductivity in the absence of illumination?…”