Enhanced Photocurrent Density by Spin-Coated NiO Photocathodes for N-Annulated Perylene-Based p-Type Dye-Sensitized Solar Cells

• The low photocurrent density of p-type dye sensitized solar cells (p-DSSCs) has limited the development of high-efficiency tandem cells due to the inadequate light harvesting ability of sensitizers and the low hole mobility of semiconductors. Hereby, two new "push-pull" type organic dyes (PQ-1 and PQ-2) containing N-annulated perylene as electron donor have been synthesized, where the PQ-2-based p-DSSCs show higher photoelectric conversion efficiency (PCE) of 0.316% owing to the higher molar extinction compared to of that PQ-1. Additionally, the photocurrent densities were remarkably increased from 2.20 to 5.85 mA cm(-2) for PQ-1 and 2.45 to 6.69 mA cm(-2) for PQ-2 by spin coated NiO photocathode based-p-DSSCs, respectively. This results are ascribed to the enhancement of hole transport rate, dye loading amounts and transparency of NiO films in comparison to that prepared by screen-printing method. Electrochemical impedance spectroscopy and theoretical calculations studies indicate that the molecular dipole moment approaching closer to the NiO surface shifts the quasi-Fermi level to more positive levels, improving,open-circuit voltage (V-oc). Intensity-modulated photocurrent spectroscopy illustrates that the hole transit time in NiO films prepared in spin-coating is shorter than that prepared by screen-printing method.

Subject headings

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

p-type dye-sensitized solar cells

spin-coated NiO photocathode

N-annulated perylene

quinoxaline

organic sensitizer

Publication and Content Type

ref (subject category)

art (subject category)