Carbonized Bamboo‐Derived Carbon Nanodots as Efficient Cathode Interfacial Layers in High‐Performance Organic Photovoltaics

Abstract

AbstractIn this study, water‐dispersed carbonized bamboo‐derived carbon nanodot (CND) is prepared through thermal dissociation followed by aqueous extraction. The CND exhibits high photoluminescence with a value of λem of 430 nm and a fluorescence quantum yield of 4.2%, a particle size of ≈3–5 nm, and presents both COOH and OH functionalities. The CND serves as cathode interfacial layer that efficiently increases the power conversion efficiencies of both fullerene‐ and nonfullerene‐based organic photovoltaics (OPVs). Embedding the CND alters the work function and surface roughness of the ZnO layer and, thereby, affects the morphologies of the active layers as well as the charge selectivity and transportation. The resulting increases in electron transport and extraction of the OPV devices lead to increases in the fill factor (FF) and short‐circuit current density (Jsc). The greatest OPV performance is that of a poly[4,8‐bis(5‐(2‐ethylhexyl)thien‐2‐yl)benzo[1,2‐b:4,5‐b′‐dithiophene‐co‐3‐fluorothieno[3,4‐b]thiophene‐2‐carboxylate]:phenyl‐C71‐butyric acid methyl ester device incorporating the CND—the PCE is 9.6% and the FF is a remarkable 72.8%.