Very high open-circuit voltage in dual-gate graphene/silicon heterojunction solar cells. (November 2018)

• Record Type: Journal Article
• Authors: Won, Ui Yeon; Ly, Thuc Hue; Kim, Young Rae; Kang, Won Tae; Shin, Yong Seon; Lee, Ki Young; Heo, Jin Seong; Kim, Kun Nyun; Lee, Young Hee; Yu, Woo Jong
• Is Part Of: Nano energy. Volume 53(2018)
• Page Start: 398
• Page End: 404
• Publication Date: 2018-11
• Subjects: Graphene/silicon -- Dual gate -- Heterojuction -- Solar cell -- Shockley and Queisser (S-Q) limit; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2018.08.052
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Two dimensional (2D) layered materials and their heterojunctions with other materials are attracted because of their remarkable electrical and optical properties. In particular, graphene/semiconductor Schottky heterojunction is used for high performance solar cells. Here, we demonstrated very high open circuit voltage ( V oc ) in graphene/silicon heterojunction solar cell by dual-gate electric field application. The low density of states near Dirac point in graphene allows large modulation of graphene Fermi-level and corresponding Schottky barrier in a graphene/silicon junction. The top and bottom gate electric fields independently adjust the built-in potentials of respective upper and lower silicon energy band to induce higher band bending (1.22 eV) than the bandgap (1.12 eV). As a result, a maximum V oc of 0.94 V is achieved at the − 8 V of top-gate voltage and 10 V of bottom-gate voltage, exceeding highest known V oc for previous graphene/silicon solar cell ( V oc = 0.61 V) and the S-Q Limit (0.84 V) of conventional silicon solar cell – a thermodynamic limit for the energy conversion efficiency of solar cells with a single band gap energy. The ratio of output power gain to input gate power (Δ P G /Δ P C ) is approximately 10 12 –10 14 with negligible power consumption in the gate ( P C = 1 fW/cm 2 –10 pW/cm 2 ), resulting in the significant advances in the power generation ( P G = 40 mW/cm 2 ). Graphical abstract: fx1 Highlights: Graphene/silicon hetero-junction solar cell was demonstrated by applying dual gate bias in 1-sun condition. Highest Open circuit voltage over the S-Q limit was recorded by modulating electrostatic doping. The ratio of output power gain to input gate power (Δ P G /Δ P C ) is approximately 10 12 –10 14 with negligible power consumption in the gate ( P C = 1 fW/cm 2 – 10 pW/cm 2 ).