Method of determining the exciton diffusion length using optical interference effect in Schottky diode

Abstract

A general model of calculating the short circuit photocurrent and exciton diffusion length from Schottky diode is given here using optical interference method. This method of estimating the exciton diffusion length can be very useful for those materials that do not give photoluminescence. It also serves as an accurate and simple method to determine the exciton diffusion length, which is an important material property to design devices such as organic solar cells. Our model is verified with the spectral response of indium tin oxide (ITO)/copper phthalocyanine (CuPc)/Al and ITO/CuPc/Ag Schottky diodes.

Determination of optical constants of pentacene thin film by spectroscopic ellipsometry

“…Vital information can be obtained from the table in terms of optical transitions between the energy levels and suitability of the model dielectric functions. In addition, the parameters can be directly used to generate optical constants to be used for numerical modeling of thin film devices [3,13,30]. Notably, the energy terms from all the models Table 1 Optical parameters of pentacene from ellipsometric analysis using Classical-Oscillator (CO), Forouhi-Bloomer (FB) and Tauc are extracted with highest accuracies as compared to the amplitude and broadening terms.…”

Cascade-type excitation energy relay in organic thin-film solar cells

“…The P6T layer might disrupt exciton travel when it is thicker than its diffusion length, resulting in decreased IPCE from BP3T. This finding again indicates that the BP3T exciton is transferred to the CuPc layer via the P6T layer, and the thickness of 70 nm might mean that the P6T exciton diffusion length is relatively large compared with that of other organic thin-film semiconductors, which generally have exciton diffusion lengths of several nanometers to a few tens of nanometers [25,41,[43][44][45]. More detailed studies need to be conducted to estimate the exciton diffusion length, which requires measurement of the ET interaction lengths between BP3T and P6T and between P6T and CuPc.…”

Light harvesting in organic solar cells using a nanostructured ITO grating

“…Due to large absorption coefficients, generally in the order of cm / 10 5 [4] organic conjugated polymers are suitable for many light absorption applications. Although such high absorbance is suitable for making OPVs thinner than their inorganic counterparts, this is actually required due to poor charge transport properties, and exciton diffusion lengths on the order of a few nanometers [5,6]. To improve the performance of OPV devices a great deal of effort is being put into ameliorating these drawbacks by implementing a number of design, materials and electrode modifications.…”