Preparation and employment of carbon nanodots to improve electron extraction capacity of polyethylenimine interfacial layer for polymer solar cells.

The performance of polymer solar cells is substantially enhanced by introducing carbon nanodots as additives in polyethylenimine buffer layer. The most pronounced effect is observed in one type of device with the average power conversion efficiencies increased from 5.78% to 7.56% after the addition of carbon nanodots at an optimal concentration in the interfacial layer, which is mainly attributed to the enhanced light trapping and electron transfer in the devices. Besides the light-harvesting and electron transport capacity improvement, the addition of carbon nanodots can also increase exciton generation and dissociation, leading to a high electron mobility. This study demonstrates a facile approach for enhancing the efficiencies of polymer solar cells. [ABSTRACT FROM AUTHOR]