Relation between Morphology and Recombination Kinetics in Nanostructured Hybrid Solar Cells

Abstract

Systematic performance improvement of excitonic solar cells hinges on thorough knowledge of their main loss mechanisms. Accordingly, the study of recombination kinetics is indispensable, enabling to identify and quantify what is considered the most important loss pathway for such devices. In contrast to the advances made in controlling the morphology of organic bulk heterojunction solar cells, it remains challengin to establish a robust correlation between morphology and recombination kinetics. Most obvious culpritsare the rather disordered nature of most heterojunctions and the absence of phase purity. In that respect, hybrid solar cells based on ZnO nanorod arrays and poly(3- hexylthiophene) can offer a convenient means to study recombination, as their morphology is easier to control and to quantify. Therefore, tunability of bulk and interfacial morphology of such solar cells is utilized in this work to evidence a direct relation between morphology, recombination kinetics and device performance.