Single Atomically Sharp Lateral Monolayer p‐n Heterojunction Solar Cells with Extraordinarily High Power Conversion Efficiency

• Published in: Advanced materials (Weinheim) Vol. 29; no. 32
• Main Authors: Tsai, Meng‐Lin, Li, Ming‐Yang, Retamal, José Ramón Durán, Lam, Kai‐Tak, Lin, Yung‐Chang, Suenaga, Kazu, Chen, Lih‐Juann, Liang, Gengchiau, Li, Lain‐Jong, He, Jr‐Hau
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2017; Wiley
• Subjects: 2D materials; Devices; Efficiency; Energy conversion efficiency; Feasibility studies; Heterojunctions; Heterostructures; Illumination; lateral heterostructures; Materials science; Molybdenum disulfide; monolayer; Photovoltaic cells; Properties (attributes); Solar cells; SOLAR ENERGY; transition metal dichalcogenides; monolayer; lateral heterostructures; solar cells; transition metal dichalcogenides; 2D materials
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201701168

The recent development of 2D monolayer lateral semiconductor has created new paradigm to develop p‐n heterojunctions. Albeit, the growth methods of these heterostructures typically result in alloy structures at the interface, limiting the development for high‐efficiency photovoltaic (PV) devices. Here, the PV properties of sequentially grown alloy‐free 2D monolayer WSe2‐MoS2 lateral p‐n heterojunction are explores. The PV devices show an extraordinary power conversion efficiency of 2.56% under AM 1.5G illumination. The large surface active area enables the full exposure of the depletion region, leading to excellent omnidirectional light harvesting characteristic with only 5% reduction of efficiency at incident angles up to 75°. Modeling studies demonstrate the PV devices comply with typical principles, increasing the feasibility for further development. Furthermore, the appropriate electrode‐spacing design can lead to environment‐independent PV properties. These robust PV properties deriving from the atomically sharp lateral p‐n interface can help develop the next‐generation photovoltaics. By sequential growth of alloy‐free 2D monolayer WSe2‐MoS2 lateral p‐n heterojunction, photovoltaic devices show extraordinary power conversion efficiencies of 2.56%. The large surface active area of the devices enables the full exposure of the depletion region, leading to excellent omnidirectional light harvesting characteristic. Modeling studies demonstrate the devices comply with typical principles. The appropriate electrode‐spacing design leads to environment‐independent properties.