Bimolecular recombination coefficient calculation by <i>in situ</i> potentiometry in a bulk heterojunction organic photovoltaic material

Danielson, Eric; Ooi, Zi En; Lombardo, Christopher; Dodabalapur, Ananth

doi:10.1063/1.4803512

Cited by 5 publications

(20 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bimolecular recombination within these materials is supported from the relationship between the conductivity and the incident light intensity. 12,17 Similar to earlier reports on vertical P3HT∶PC 61 BM solar cells, 26,27 the bimolecular recombination coefficient is orders of magnitude smaller than the Langevin recombination coefficient; in this case, B∕B L is ∼0.0068. In situ potentiometry measurements on lateral devices can, therefore, be used to find several important parameters within BHJ materials, listed in Table 2.…”

Section: In Situ Potentiometrysupporting

confidence: 70%

“…[12][13][14] Due to these large biases, large regions of space charge form adjacent to the electrodes even when the carrier mobilities are similar. If the mobilities are mismatched, the space charge region (SCR) dominated by the slower carrier grows in size while the other shrinks.…”

Section: Theorymentioning

confidence: 99%

“…SCL behavior, with an exponent m close to 0.5, is observed from 0 to 3 μm and 14.1 to 20 μm, defining the extent of SCRs. 12 The larger SCR adjacent to the anode indicates that holes are the slower carrier within the BHJ. A voltage exponent close to 1, consistent with the ohmic behavior predicted in the RZ, is observed from 4.6 to 12.6 μm within the device channel.…”

Section: In Situ Potentiometrymentioning

confidence: 99%

See 2 more Smart Citations

Analysis of bulk heterojunction material parameters using lateral device structures

et al. 2014

Self Cite

View full text Add to dashboard Cite

Abstract. We review the key optoelectronic properties of lateral organic bulk heterojunction (BHJ) device structures with asymmetric contacts. These structures are used to develop a detailed model of charge transport and recombination properties within materials used for organic photovoltaics. They permit a variety of direct measurement techniques, such as nonlinear optical microscopy and in situ potentiometry, as well as photoconductive gain and carrier drift length studies from photocurrent measurements. We present a theoretical framework that describes the charge transport physics within these devices. The experimental results presented are in agreement with this framework and can be used to measure carrier concentrations, recombination coefficients, and carrier mobilities within BHJ materials. Lateral device structures offer a useful complement to measurements on vertical photovoltaic structures and provide a more complete and detailed picture of organic BHJ materials. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

show abstract

Section: In Situ Potentiometrysupporting

confidence: 70%

Section: Theorymentioning

confidence: 99%

Section: In Situ Potentiometrymentioning

confidence: 99%

See 1 more Smart Citation

Analysis of bulk heterojunction material parameters using lateral device structures

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…10,[12][13][14] We use this to analyze charge transport properties within the bulk of the material. Although the bias voltages we employ are large, the value of the electric field in these structures is similar to that present in a typical vertical solar cell device.…”

Section: Theorymentioning

confidence: 99%

“…9 We have developed a set of complementary methods based on lateral BHJ devices to measure charge transport along the in-plane axis, or lateral direction. [10][11][12][13][14] In a lateral BHJ device, both electrodes lie on the same plane and the photoactive region is defined by the channel between the two electrodes ( Fig. 1(a)).…”

mentioning

confidence: 99%

Use of lateral structures to monitor and evaluate degradation of key photovoltaic parameters in an organic bulk heterojunction material

Danielson

Ooi

Dodabalapur

2014

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

Charge transport and recombination mechanisms within organic bulk heterojunction (BHJ) systems have been studied using lateral devices to perform in situ potentiometry. We have developed a simplified measurement technique using two types of lateral structures to elicit key charge transport parameters and study the time and process dependence of the carrier mobilities and their ratio. Small geometry lateral devices are used to evaluate the mobility of the slower carrier within the P3HT:PCBM material system. Larger structures with 5 in situ voltage probes are used to construct a simple potential profile of the device channel and accurately determine the carrier mobility ratio. These two measurements enable the calculation of carrier densities and the recombination coefficient. We monitor the change in these parameters as the P3HT:PCBM film degrades in the presence of oxygen and also examine the effect of the solvent additive 1,8-diiodooctane on this degradation mechanism. By exposing ethanol vapor to the BHJ film, we induce traps in the material and monitor the shift in dominant nongeminate recombination mechanism to a more unimolecular type. We are also able to measure the resulting decrease in carrier mobilities due to the presence of dipole-induced traps. Lateral devices are useful material diagnostic structures for studying degradation in BHJ materials.

show abstract

Evaluating Charge Carrier Mobility Balance in Organic Bulk Heterojunctions using Lateral Device Structures

et al. 2014

Self Cite

View full text Add to dashboard Cite

Lateral geometry devices are useful structures to probe the charge transport properties of organic bulk heterojunction materials. In this work, we describe the lateral device as effectively having three distinct zones: two photogenerative space-charge regions next to each electrode and a middle zone that has high recombination rate. We analyze how photocurrent depends on electron and hole mobilities and recombination strength and, based on this analysis, demonstrate a steady-state method for extracting both carrier mobilities and the recombination coefficient from potentiometry and photocurrent data.

show abstract

Bimolecular recombination coefficient calculation by in situ potentiometry in a bulk heterojunction organic photovoltaic material

Abstract: Articles you may be interested inUse of lateral structures to monitor and evaluate degradation of key photovoltaic parameters in an organic bulk heterojunction material

Cited by 5 publications

References 17 publications

Analysis of bulk heterojunction material parameters using lateral device structures

Analysis of bulk heterojunction material parameters using lateral device structures

Use of lateral structures to monitor and evaluate degradation of key photovoltaic parameters in an organic bulk heterojunction material

Evaluating Charge Carrier Mobility Balance in Organic Bulk Heterojunctions using Lateral Device Structures

Contact Info

Product

Resources

About