Graphene Intermediate Layer in Tandem Organic Photovoltaic Cells

✍ Scribed by Shi Wun Tong; Yu Wang; Yi Zheng; Man-Fai Ng; Kian Ping Loh

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 672 KB
• Volume: 21
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/adfm.201101376

✦ Synopsis

One strategy to harvest wide spectral solar energy is to stack different bandgap materials together in a tandem solar cell. Here, it is demonstrated that CVD grown graphene fi lm can be employed as intermediate layer (IML) in tandem solar cells. Using MoO 3 -modifi ed graphene IML, a high open circuit voltage (V oc ) of 1 V and a high short-circuit current density (J sc ) of 11.6 mA cm -2 could be obtained in series and parallel connection, respectively, in contrast to a V oc of 0.58 V and J sc of 7.6 mA cm -2 in single PV cell. The value of V oc (J sc ) in the tandem cell is very close to the sum of V oc (J sc ) attained from two single subcells in series (parallel), which confi rms good ohmic contact at the photoactive layer/MoO 3 -modifi ed graphene interface. Work function engineering of the graphene IML with metal oxide is essential to ensure good charge collection from both subcells.