Compressed sensing current mapping methods for PV characterisation

Koutsourakis, George; Cashmore, Matt; Bliss, Martin; Hall, Simon R. G.; Betts, Thomas R.; Gottschalg, Ralph

doi:10.1109/pvsc.2016.7749827

Cited by 5 publications

(2 citation statements)

References 14 publications

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“…Similar to JPEG image compression, the sequence of patterns measures and compresses the necessary information, in order to successfully reconstruct the photocurrent response map. This is a standard procedure for optical CS imaging systems [33] that is analytically described for CS current mapping of photovoltaic (PV) devices in [34]. Compared to a point-by-point scan, fewer measurements are required in order to produce a current map of a sample.…”

Section: Methodsmentioning

confidence: 99%

Signal Amplification Gains of Compressive Sampling for Photocurrent Response Mapping of Optoelectronic Devices

Koutsourakis

Blakesley

Castro

2019

Sensors

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Spatial characterisation methods for photodetectors and other optoelectronic devices are necessary for determining local performance, as well as detecting local defects and the non-uniformities of devices. Light beam induced current measurements provide local performance information about devices at their actual operating conditions. Compressed sensing current mapping offers additional specific advantages, such as high speed without the use of complicated experimental layouts or lock-in amplifiers. In this work, the signal amplification advantages of compressed sensing current mapping are presented. It is demonstrated that the sparsity of the patterns used for compressive sampling can be controlled to achieve significant signal amplification of at least two orders of magnitude, while maintaining or increasing the accuracy of measurements. Accurate measurements can be acquired even when a point-by-point scan yields high noise levels, which distort the accuracy of measurements. Pixel-by-pixel comparisons of photocurrent maps are realised using different sensing matrices and reconstruction algorithms for different samples. The results additionally demonstrate that such an optical system would be ideal for investigating compressed sensing procedures for other optical measurement applications, where experimental noise is included.

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Section: Methodsmentioning

confidence: 99%

Signal Amplification Gains of Compressive Sampling for Photocurrent Response Mapping of Optoelectronic Devices

Koutsourakis

Blakesley

Castro

2019

Sensors

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“…The schematic of the system is reported in figure 1 and is analytically described in [14]. The 70 mW output of a singlemode pig tailed 637 nm laser diode (Thorlabs LP637 SF70 driven with a Thorlabs LDC202C and temperature controller Thorlabs TED200C) is collimated through a 25.4 mm diameter convex lens with a focal length of 200 mm and overfills the DMD (ViALUX V-7000 module).…”

Section: Methodsmentioning

confidence: 99%

High-speed digital light source photocurrent mapping system

Bausi

Koutsourakis

Blakesley

et al. 2019

Meas. Sci. Technol.

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High-resolution spatial characterization of photovoltaic devices and photodetectors can reveal local defects that can have a detrimental impact on the lifetime and performance of such devices. Photocurrent mapping methods can provide high-resolution measurements and characterization can be achieved under actual operating conditions. However, such methods usually require costly, complicated systems and possess limited measurement speed. In this work an optical system based on a digital micro-mirror device is used for photocurrent mapping and a measurement protocol with a theoretical upper limit for scanning rate of 22 kHz is presented. The digital micromirror device itself provides synchronised spatial and temporal modulation in order to perform current mapping. Photocurrent maps of solar cells devices obtained with a scanning rate of 1000 pixels in less than 6 s are reported (the speed was limited by the device’s response time and its photon to current conversion efficiency). The speed of photocurrent mapping is thus increased by almost two orders of magnitude compared to other methods and is only limited by the response of the device under test. A lateral resolution of 34 µm is achieved, with the potential to increase it even further. The absence of any moving parts allows high repeatability of measurements. Combined with the high-speed control of the light field, this enables the development of novel measurement techniques for the simultaneous measurement of temporal and spatial parameters. The fully digital control of the mapping system also presents a high potential for integration in industrial automated systems as it can be fully controlled using machine learning algorithms to achieve fast detection of crucial defects and features of devices during manufacturing.

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Compressive light beam induced current sensing for fast defect detection in photovoltaic cells

Lei

Xie

et al. 2017

Solar Energy

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Compressed sensing current mapping methods for PV characterisation

Cited by 5 publications

References 14 publications

Signal Amplification Gains of Compressive Sampling for Photocurrent Response Mapping of Optoelectronic Devices

Signal Amplification Gains of Compressive Sampling for Photocurrent Response Mapping of Optoelectronic Devices

High-speed digital light source photocurrent mapping system

Compressive light beam induced current sensing for fast defect detection in photovoltaic cells

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