title: Cesium carbonate functionalized graphene quantum dots as stable electron-selective layer for improvement of inverted polymer solar cells.
abstract: Solution processable inverted bulk heterojunction (BHJ) polymer solar cells (PSCs) are promising alternatives to conventional silicon solar cells because of their low cost roll-to-roll production and flexible device applications. In this work, we demonstrated that Cs2CO3 functionalized graphene quantum dots (GQDs-Cs2CO3) could be used as efficient electron-selective layers in inverted PSCs. Compared with Cs2CO3 buffered devices, the GQDs-Cs2CO3 buffered devices show 56% improvement in power conversion efficiency, as well as 200% enhancement in stability, due to the better electron-extraction, suppression of leakage current, and inhibition of Cs(+) ion diffusion at the buffer/polymer interface by GQDs-Cs2CO3. This work provides a thermal-annealing-free, solution-processable method for fabricating electron-selective layer in inverted PSCs, which should be beneficial for the future development of high performance all-solution-processed or roll-to-roll processed PSCs.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 62 Nanyang Drive, 637459, Singapore.
authors.forename: Hong Bin
authors.initials: HB
authors.lastname: Yang
authors.forename: Yong Qiang
authors.initials: YQ
authors.lastname: Dong
authors.forename: Xizu
authors.initials: X
authors.lastname: Wang
authors.forename: Si Yun
authors.initials: SY
authors.lastname: Khoo
authors.forename: Bin
authors.initials: B
authors.lastname: Liu