9 Parts-Per-Million-Level Doping Effects …
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Fig. 9.6 a Structure of a tandem cell incorporating two pn-homojunction C 60 cells connected by
an n + p + -homojunction. b Structure of a C 60 unit cell incorporating a pn-homojunction. c Current–
voltage (J-V ) characteristics for the tandem cell (curves A)(Fig. 9.6a) and the unit cell (curves B)
(Fig. 9.6b). Curves C are for a tandem cell without an n + p + -interconnecting homojunction. The
photo and dark currents are shown by solid and broken curves, respectively. The ITO electrode
was irradiated with simulated solar light (AM1.5, 100 mWcm −2 ). The short-circuit photocurrent,
open-circuit photovoltage (V oc ), fill factor, and efficiency of the cells: (A) 0.09 mAcm −2 , 1.90 V,
0.29, 0.05%. (B) 0.29 mAcm −2 , 1.03 V, 0.34, 0.10%. (C) 0.06 mAcm −2 , 1.03 V, 0.32, 0.02%.
d Energy band diagram of a tandem cell based on Kelvin probe measurements. The blue and redshaded regions correspond to the depletion layers for the pn- and n + p + -homojunctions, respectively.
Reproduced with permission from [39]. Copyright 2012 AIP Publishing
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Fig. 9.6 a Structure of a tandem cell incorporating two pn-homojunction C 60 cells connected by
an n + p + -homojunction. b Structure of a C 60 unit cell incorporating a pn-homojunction. c Current–
voltage (J-V ) characteristics for the tandem cell (curves A)(Fig. 9.6a) and the unit cell (curves B)
(Fig. 9.6b). Curves C are for a tandem cell without an n + p + -interconnecting homojunction. The
photo and dark currents are shown by solid and broken curves, respectively. The ITO electrode
was irradiated with simulated solar light (AM1.5, 100 mWcm −2 ). The short-circuit photocurrent,
open-circuit photovoltage (V oc ), fill factor, and efficiency of the cells: (A) 0.09 mAcm −2 , 1.90 V,
0.29, 0.05%. (B) 0.29 mAcm −2 , 1.03 V, 0.34, 0.10%. (C) 0.06 mAcm −2 , 1.03 V, 0.32, 0.02%.
d Energy band diagram of a tandem cell based on Kelvin probe measurements. The blue and redshaded regions correspond to the depletion layers for the pn- and n + p + -homojunctions, respectively.
Reproduced with permission from [39]. Copyright 2012 AIP Publishing