Transient current study in safranine-T dye based organic photo-electrochemical cell using exponentially distributed trap assisted charge transport model

Islam, Md. Rabiul; Saha, Sudeshna; Manik, Nabin Baran; Basu, A. N.

doi:10.1007/s12648-012-0170-7

Cited by 2 publications

(1 citation statement)

References 27 publications

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“…With an increase in trap charge density, the recombination of charges increase and also the mobility gets reduced. For the last few years, we have been studying the effects of traps in organic dye based photovoltaic devices [12][13][14][15][16][17]. Efforts to reduce the trap energy of these devices are being carried out as it would lower the rate of recombination and thereby enhance the conduction of charges through these devices.…”

Section: Introductionmentioning

confidence: 99%

Improvement of electrical and photovoltaic properties of methyl red dye based photoelectrochemical cells in presence of single walled carbon nanotubes

Chakraborty

Manik

2015

Front. Optoelectron.

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In this work, we investigated the effect of single walled carbon nanotubes (SWCNT) on the electrical and photovoltaic properties of methyl red (MR) dye based photoelectrochemical cell (PEC). MR dye based PEC with LiClO 4 as ion salt were fabricated with and without mixing SWCNT. The cells were characterized through electrical and optical measurements. The performance of the devices changed drastically in presence of SWCNT. The transition voltage and trap energy of the cells were estimated from the steady-state dark current voltage (I-V) analysis. The transition voltage and trap energy decreased for MR dye cell in presence of SWCNT. Open circuit voltage (V oc ), short circuit current (J sc ), fill factor (FF) and power conversion efficiency (η) increased due to the addition of SWCNT. Further measurement of the transient photocurrent showed that the growth and decay of photocurrent was quite faster in presence of SWCNT. The photocurrent decay with time was fitted for both the cells and found to follow a power law relation which indicates dispersive transport mechanism with exponential trap states distributed in between lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) levels. Possible interpretation is done on the lowering of trap energy with the photocurrent. These results suggest that SWCNT lowers the trap energy of the cells by providing efficient percolation pathways for the conduction of charges. It is expected that due to lowering of trap energy the residing time of the free carriers within the traps decreases. In other words, it may also be said that the charge recombination decreases. These factors affect the overall conduction of charges and improve the electrical and photovoltaic properties.

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