Novel Strategies to Improve the Efficiency and Stability of Binary-Based Organic Photovoltaic Devices

Abstract

The power conversion efficiency (PCE) of organic solar cells (OPVs) has been promptly improved once emerging the recently developed non-fullerene small-molecules acceptors (NFAs), approaching PCE of 20%. This remarkable increase in the power conversion efficiencies was due to the significant enhancement in the light absorption along with diminishing the energy losses, particularly upon minimizing the trade-off behavior between voltage loss and charge generation in nonfullerene organic solar cells (NF–OPVs). Despite the efficiency, long lization of OPVs. Severalstrategies have been investigated to understand the intrinsic photo-degradation mechanism in order to overcome this recent demanding subject. Some of these avenues concern the stability of the bulk-heterojunction photoactive blend microstructure through additives modifications to tune the properties of the photo-active layer.In this thesis, we combined the interfacial engineering, morphology control, and third component strategies to improve the OPV devices performance and stability. First, we conducted an intermittent spray pyrolysis approach to deposit the ZnO interfacial layers in fullerene based inverted OPVs. It significantly enhanced the interface morphology, resulting in remarkable stability behaviour of the sprayed devices. Then, we focused on optimizing the blend morphology based on the NFOPV devices through additives and thermal treatment.