Spectroscopic and impedance studies of reverse biased degraded dye solar cells

Photoelectrochemical Response of DSSCs Under Prolonged Reverse Bias and Conduction Band Lowering in Ru‐Complex‐Sensitized TiO2

“…Under these circumstances the breakdown of the DSSC was clearly associated with the irreversible chemical modification of the dye in agreement with previous reports 30. 31 In this work, the behavior of DSSCs sensitized with Ru‐complexes N719 and Z907 and undergoing prolonged RB stress is investigated. The RB regime is imposed in dark conditions at room temperature.…”

“…This is indicated by the lower absorption in the visible region and by the blue shift of the absorption peak of the dyes, and probably involves the loss of the SCN ligands 25. 31 The noticeable changes observed in the cell response due to the shift of the CB edge and the simultaneous slowing down of the recombination process indicate that the RB stress drives some changes at the TiO 2 –dye/electrolyte interface. A plausible explanation can be found in the recent literature.…”

“…Past studies concerning the degradation of DSSCs subjected to RB have shown how this treatment impacts the cells at different levels. In particular, two papers30, 31 reported a dramatic loss in conversion efficiency upon application of an RB of not less than 2 V to Ru‐based cells, and attributed these results to the irreversible oxidation of the Ru complex and/or to the loss of the SCN ligands. Recently, Mastroianni et al.…”

Micro-Raman analysis of reverse bias stressed dye-sensitized solar cells

“…A number of contributions have dealt with the RB problem and most of them have considered solar devices based on the bis-thiocyanato ruthenium dye, N719. [12][13][14][15] Reduction of cell efficiency has been correlated in general to the loss of coordinated NCS À ligands. 13 Wheatley et al analyzed reverse biased DSCs applying various constant voltages to the cell (up to 3000 mV) and observing the induced phenomena by Raman spectroscopy and spectroelectrochemical analysis.…”

Polyiodides formation in solvent based Dye Sensitized Solar Cells under reverse bias stress

“…Here we focus on one of the main source of DSSC degradation, namely the reverse bias (RB) stress, which is induced, for example, by partial shadowing of a DSSC panel. [17,18] The degradation mechanisms that affect the electrolyte and the origin of marked M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 fluorescence, both due to the RB stress, will be investigated by using micro Raman [19] and fluorescence spectroscopy. We identified that the Raman signals of the electrolyte aggregations on platinized counter electrode induced by RB stress tests, are related to typical polyiodide bands.…”