Phthalocyanine organic solar cells: Indium/x-metal free phthalocyanine Schottky barriers

Journal Article · Sat Aug 01 04:00:00 EDT 1981 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.329425· OSTI ID:6377298

Loutfy, R O; Sharp, J H; Hsiao, C K; Ho, R

A thin organic film of polycrystalline particles of x-metal free phthalocyanine (x-H/sub 2/Pc) dispersed in a polymer binder, when sandwiched between tin oxide (NESA) and indium electrodes, is shown to exhibit a strong photovoltaic effect. The photovoltaic and rectification properties of In/x-H/sub 2/Pc/NESA sandwich cells are reported. From the photovoltaic action spectra, the active region responsible for electric power generation was found to be confined to the metal/semiconductor interface. A Schottky barrier width of 300 A was determined, which allows the capture of 30% of solar irradiance. An electron trap density of 3 x 10/sup 17//cm/sup 3/ and a Schottky barrier built-in potential of 0.63 V are estimated from C-V measurements. At low voltage, the dark current in the forward direction varies exponentially with voltage: from this dependence values of 2 x 10/sup -9/ A/cm/sup 2/ and 1.3--2.6 for the saturation current J/sub 0/ and diode quality factor n are determined. At higher voltage, a super quadratic dependence of forward current on voltage indicated that current conduction is limited by an exponentially decreasing distribution of traps. At peak solar power (135 mW/cm/sup 2/), a power conversion efficiency (eta') of 1.2% to transmitted light has been obtained. The transmittance of the indium electrode approached 2%. The devices exhibit open circuit voltages V/sub o/c of 0.45 V and short-circuit currents of 0.2 mA/cm/sup 2/ at Air Mass Zero (AMO) sunlight. Therefore, the engineering efficiency of our device approached 0.03%. The monochromatic quantum efficiency of free-carrier generation approached 75% at low light level; this diminished to 30% at solar intensities, characteristic of a cell with large series resistance. The effect of pigment loading, cell thickness, light intensity, binder material, dye sensitization, and the nature of barrier electrode has been studied and optimized.

• Research Organization: Xerox Research Centre of Canada, 2480 Dunwin Drive, Mississauga, Ontario L5L 1J9, Canada
• OSTI ID: 6377298
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 52:8; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
CARRIER DENSITY
CHALCOGENIDES
CRYSTALS
DATA
DIRECT ENERGY CONVERTERS
DYES
EFFICIENCY
ELECTRIC POTENTIAL
ELECTRICAL EQUIPMENT
ELECTRODES
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
EQUIPMENT
EXPERIMENTAL DATA
FERMIONS
FILMS
HETEROCYCLIC COMPOUNDS
INDIUM
INFORMATION
LEPTONS
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SOLAR CELLS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOELECTROMAGNETIC EFFECTS
PHOTOVOLTAIC CELLS
PHOTOVOLTAIC EFFECT
PHTHALOCYANINES
POLYCRYSTALS
POLYMERS
QUANTUM EFFICIENCY
RECTIFIERS
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SOLAR CELLS
SOLAR EQUIPMENT
TIN COMPOUNDS
TIN OXIDES
TRAPPED ELECTRONS