Efficient organic solar cells by penetration of conjugated polymers into perylene pigments

金沢大学理工研究域物質化学系We report here efficient air-stable p-n heterojunction organic solar cells with a structure consisting of an n-type insoluble perylene pigment penetrated by a p-type-conjugated polymer, where the interfacial area for photocurrent generation increases. The solar cells are easily produced by infiltrating a soluble-conjugated polymer intentionally into an opening among insoluble microcrystalline perylene layer under a saturated chloroform vapor. This approach can be regarded as an alternative convenient way to achieve bulk heterojunction solar cells. The cell performance is further enhanced by inserting an additional layer between the electrode and the photoactive layer to confine exciton in the photoactive layer. The overall attempt to improve the cell performance, so far, results in maximum quantum efficiency up to 45% under illumination of 485-nm monochromatic light and power conversion efficiency up to 1.9% under a simulated solar light (AM1.5) with a 100 mW cm-2 intensity. The approach is promising to achieve practical efficiency because tuning the opening size can further widen the photoactive area. © 2004 American Institute of Physics

Porphyrin dye-sensitization of polythiophene in a conjugated polymer/TiO2 p-n hetero-junction solar cell

金沢大学工学部In the blended solid of poly(3-hexylthiophene-2,5-diyl) (P3HT) and porphyrin (TPP)/TiO2 p-n hetero-junction solar cells, a photo-induced charge transfer between P3HT and TPP accelerated the charge separation in the depletion layer formed at the P3HT + TPP/TiO2 interface, enhancing the photovoltaic properties. For the blended cell containing zinc porphyrin as TPP, the energy conversion yield of 0.26% was obtained under the illumination of solar simulated light AM1.5-100 mW/cm2

The photovoltaic mechanism of a polythiophene/perylene pigment two-layer solar cell

The energy conversion efficiency of a two-layer organic solar cell consisting of a perylene pigment (PV) and regioregular polythiophene polymer (P3DT) was 0.99% under illumination with simulated solar light (AM 1.5–100 mW cm−2). The photovoltaic mechanism is discussed on the basis of the ionization potential of the component materials. The photoinduced hole-transfer from PV to P3DT quickly occurred at the PV/P3DT interface because of the large free energy change of 1.2 eV, then the subsequent charge separation efficiently proceeded, resulting in a large short-circuit photocurrent of 6.5 mA cm−2. On the other hand, the open-circuit photovoltage was only 0.42 V because the LUMO level of PV is close to the HOMO level of P3DT. The difference between the LUMO and the HOMO can be attributed to the open-circuit photovoltage

The photovoltaic mechanism of a polythiophene/perylene pigment two-layer solar cell

The energy conversion efficiency of a two-layer organic solar cell consisting of a perylene pigment (PV) and regioregular polythiophene polymer (P3DT) was 0.99% under illumination with simulated solar light (AM 1.5–100 mW cm−2). The photovoltaic mechanism is discussed on the basis of the ionization potential of the component materials. The photoinduced hole-transfer from PV to P3DT quickly occurred at the PV/P3DT interface because of the large free energy change of 1.2 eV, then the subsequent charge separation efficiently proceeded, resulting in a large short-circuit photocurrent of 6.5 mA cm−2. On the other hand, the open-circuit photovoltage was only 0.42 V because the LUMO level of PV is close to the HOMO level of P3DT. The difference between the LUMO and the HOMO can be attributed to the open-circuit photovoltage