Researchers found conductive property of graphene promising for solar technology, according to a study published on July 10, 2018.
This study was conducted by the researchers at the University of Kansas (KU). A graphene layer was connected with two other atomic layers (molybdenum diselenide and tungsten disulfide), which led to an extension of lifetime of excited electrons in graphene by several hundred times. The results of the study will be published on Nano Futures.
According to the researchers, electrons in graphene move at a speed of 1/30 of the speed of light, which suggests that graphene can be used in solar cells. However, a major drawback of graphene that hinders its applications is its ultrashort lifetime of excited electrons. To overcome this drawback, a tri-layer material was designed in KU’s Ultrafast Laser Lab by putting single layers of MoSe2, WS2, and graphene on top of each other.
Professor Hui Zhao said, “We can think of the MoSe2 and graphene layers as two classrooms full of students all sitting, while the middle WS2 layer acts as a hallway separating the two room. When light strikes the sample, some of the electrons in MoSe2 are liberated. They are allowed to go across the WS2-layer hallway to enter the other room, which is graphene.”
As part of the demonstration, an ultrashort laser pulse was used by the researchers to liberate some of the electrons in MoSe2. The movement of electrons to graphene was monitored by using another ultrashort laser pulse. This work is expected to speed the development of ultrathin and flexible solar cells with high efficiency.