Graphdiyne oxide-accelerated charge carrier transfer and separation at the interface for efficient binary organic solar cells

Abstract

Interfacial engineering for the regulation of the charge carrier dynamics in solar cells is a critical factor in the fabrication of high-efficiency devices. Based on the successful preparation of highly dispersible graphdiyne oxide (GDYO) with a large number of functional groups, we fabricated organic solar cells employing GDYO-modified poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) as hole transport materials. Results show that the π−π interaction between GDYO and PEDOT:PSS is beneficial to the formation of an optimized charge carrier transfer channel and improves the conductivity and charge carrier mobility in the hole transport layer. Moreover, the improved interfacial contact contributes to the suppression of charge carrier recombination and the elevation of charge carrier extraction between the hole transport layer and the active layer. More importantly, the occurrence of charge carrier separation benefits from the optimized morphology of the active layer, which efficiently improves the performance, as proven by the results of transient absorption measurements. Therefore, with the holistic management approach to the multiobjective optimization of the charge carrier dynamics, a photoelectric conversion efficiency of 17.5% (with the certified value of 17.2%) is obtained for binary organic solar cells. All of these results indicate the potential application of the functionalized graphdiyne in the field of organic optoelectronic devices.