Kinetic Evidence of Two Pathways for Charge Recombination in NiO-Based Dye-Sensitized Solar Cells

Autor: Belinda Pettersson Rimgard, Gerrit Boschloo, Leif Hammarström, Liisa J. Antila, Luca D'Amario
Rok vydání: 2015
Předmět:
Zdroj: The Journal of Physical Chemistry Letters. 6:779-783
ISSN: 1948-7185
DOI: 10.1021/acs.jpclett.5b00048
Popis: Mesoporous nickel oxide has been used as electrode material for p-type dye-sensitized solar cells (DSCs) for many years but no high efficiency cells have yet been obtained. One of the main issues that lowers the efficiency is the poor fill factor, for which a clear reason is still missing. In this paper we present the first evidence for a relation between applied potential and the charge recombination rate of the NiO electrode. In particular, we find biphasic recombination kinetics: a fast (15 ns) pathway attributed to the reaction with the holes in the valence band and a slow (1 ms) pathway assigned to the holes in the trap states. The fast component is the most relevant at positive potentials, while the slow component becomes more important at negative potentials. This means that at the working condition of the cell, the fast recombination is the most important. This could explain the low fill factor of NiO-based DSCs.
Databáze: OpenAIRE