Ziv Hameiri

UNSW Sydney | UNSW · School of Photovoltaic and Renewable Energy Engineering

Light-induced degradation (LID) in boron (B)-doped Czochralski (Cz) silicon wafers has impacted commercial p-type silicon solar cells for decades. Substitution of boron with gallium (Ga) or (to a lesser extent) indium (In) has been suggested as a method to tackle this problem since Ga- and In-doped Cz wafers were shown to be less prone to LID. Alth...

The internal quantum efficiency (IQE) is given as the ratio between the externally collected electron current and the photon current absorbed by the device. Spectral analysis of IQE measurements is a powerful method to identify performance‐limiting mechanisms in solar cells. It also enables the extraction of key electrical and optical parameters. H...

Recently, the significant improvements in the surface and contact passivation of silicon (Si) solar cells as well as their bulk quality have shifted their operating point to higher injections. Hence, they are less dependent on wafer doping. This shift opens an opportunity of using high-resistivity wafers for practical photovoltaic applications, int...

A novel, camera‐based method for direct implied open‐circuit voltage (iVOC) imaging via the use of a single bandpass filter (s‐BPF) is developed for large‐area photovoltaic solar cells and precursors. The photoluminescence (PL) emission is imaged using a narrow BPF with centre energy inside the high‐energy tail of the PL emission, utilising the clo...

Bulk defects in silicon solar cells are a key contributor to loss of efficiency. To detect and identify those defects, temperature- and injection-dependent lifetime spectroscopy is usually used, and the defect parameters are traditionally extracted using fitting methods to the Shockley-Read-Hall recombination statistics. In this study, we propose a...

Solar photovoltaic installations have increased exponentially over the last decade and are now at a stage where they provide humanity with the greatest opportunity to mitigate accelerating climate change. For the continued growth and success of photovoltaic energy the reliable inspection of solar power plants is an important requirement. This ensur...

A direct, camera-based implied open-circuit voltage (iVOC) imaging method via the novel use of a single bandpass filter (s-BPF) is developed for large-area photovoltaic solar cells and solar cell precursors. This method images the photoluminescence (PL) emission using a narrow BPF with centre energy in the high-energy tail of the PL emission taking...

Understanding carrier loss mechanisms at microscopic regions is imperative for the development of high-performance polycrystalline inorganic thin-film solar cells. Despite the progress achieved for kesterite, a promising environmentally benign and earth-abundant thin-film photovoltaic material, the microscopic carrier loss mechanisms and their impa...

The operating temperature has a critical impact on the electrical performance of solar cells. It has been shown that the temperature coefficient is not uniform across devices and often varies between different regions due to the inhomogeneous distributions of defects. In this study, temperature‐dependent photoluminescence imaging measurements are u...

Perovskite solar cells (PSCs) with a power conversion efficiency (PCE) overpassed 25%, have proved to be the most promising competitor for the next‐generation photovoltaic technology. Massive efforts have been devoted to the improvement of the performance and stability of PSCs, whereas the hole‐transport layer (HTL) has attracted significant intere...

Bulk lifetime ( $\tau _{\text{bulk}}$ ) and bulk doping ( $N_{\text{dop}}$ ) are critical material parameters influencing solar cell performance. The ability to probe spatial variations in $\tau _{\text{bulk}}$ and $N_{\text{dop}}$ in ingots, prior to wafer cutting and further processing, would be beneficial to improving the yield and reducin...

Identifying solar cell efficiency shortfalls in production lines is crucial to troubleshoot and optimize manufacturing processes. With the adoption of luminescence imaging as a key end-of-line characterization tool, a wealth of information is available to evaluate cell performance and classify defects, suitable for user input-free deep-learning ana...

The cover image is based on the Research Article Advanced photoluminescence imaging using non‐uniform excitation by Shuai Nie et al., https://doi.org/10.1002/pip.3488.

Photovoltaic devices operate under a wide range of temperature and illumination conditions. While the temperature coefficients (TC) of crystalline silicon solar cells have been well-studied, there have been only a few investigations regarding the effect of illumination on TCs. In this study, the TCs of the main electrical parameters of various sili...

Extracting the parameters, energy level and electron-to-hole capture cross-section ratio, of efficiency-limiting bulk defects in silicon solar cells is a critical step in identifying those defects and potentially eliminating their impact. Typically, this is achieved on specially prepared test structures. However, in some cases, this is not possible...

Carrier loss mechanisms at microscopic regions is imperative for high-performance polycrystalline inorganic thin-film solar cells. Despite the progress on Kesterite, a promising environmental-benign and earth-abundant thin-film photovoltaic material, the microscopic carrier loss mechanisms and their impact on device performance remain unknown. Here...

The temperature coefficient (TC) is an essential figure of merit to accurately evaluate solar cell performance at various operating temperatures and hence enabling the comparison between different cell technologies. Recently, solar cells that use passivating contacts based on transition metal oxide (TMO) layers have attracted much attention due to...

A contactless effective series resistance imaging method for large area perovskite solar cells that is based on photoluminescence imaging with non-uniform illumination is introduced and demonstrated experimentally. The proposed technique is applicable to partially and fully processed perovskite solar cells if laterally conductive layers are present...

Photoluminescence (PL) imaging is a powerful inspection technique for research laboratories and photovoltaic production lines. Common PL imaging systems have two limitations: (a) due to the non-uniformities of the measured samples, the acquired images are affected by lateral carrier flow, resulting in inaccurate lifetime analysis and image blurring...

Recently, it has been shown that the investigation of minority carrier traps (traps) is a useful method to study defects in silicon wafers. In this paper, we report the presence of traps in p-type multicrystalline silicon with a photoconductance decay time constant of 1.9 ± 0.4 s (at 30 °C). It is shown that the density of traps is significantly re...

End-of-line characterization of solar cells is necessary to filter out defective cells and bin cells to avoid power mismatch loss in photovoltaic modules. Current–voltage testers, used by almost any photovoltaic company and research laboratory, are costly to maintain and to adapt to recent and predicted morphological changes in solar cells: larger...

A contactless effective series resistance imaging method for large area perovskite solar cells that is based on photoluminescence imaging with non-uniform illumination is introduced and demonstrated experimentally. The proposed technique is applicable to partially and fully processed perovskite solar cells if laterally conductive layers are present...

The sub-bandgap photoluminescence (PL) arising from dislocations in crystalline silicon (known as “D-lines”) has been studied for over half a century. However, many properties of the D-lines such as the defect parameters and the underlying recombination mechanism are poorly understood. In this study, we perform both temperature-dependent and inject...

In this study, we present an electroluminescence (EL)-based imaging method to detect broken fingers in solar cells. The method is based on the ratio of two EL images taken with different paths of the injected current. The resulted high contrast images allow unambiguous separation of various series-resistance-related problems, and hence the potentia...

Charge carrier lifetime is an important parameter for semiconductor materials. This study proposes a dynamic calibration method for injection‐dependent carrier lifetime measurements. This method is based on the comparison between lifetime measurements under quasi‐steady‐state and non‐quasi‐steady‐state conditions. The proposed method is first demon...

Silicon dioxide (SiO2) has played a critical role in the development of high-efficiency silicon (Si)-based photovoltaic devices. Recently, it has experienced a renaissance as an interlayer in many of the new contact passivating structures. Studies have extensively investigated the recombination process at the Si–SiO2 interface, however, only little...

The temperature coefficient (TC) is a critical figure of merit to accurately evaluate the performance of solar cells at various operating temperatures, and hence, enabling the comparison between different cell technologies. Recently, tunnel oxide passivated contact (TOPCon) solar cells have shown outstanding cell performance. They are likely to be...

Halide perovskite‐based photovoltaic (PV) devices have recently emerged for low energy consumption electronic devices such as Internet of Things (IoT). In this work, an effective strategy to form a hole‐selective layer using phenethylammonium iodide (PEAI) salt is presented that demonstrates unprecedently high open‐circuit voltage of 0.9 V with 18...

Carrier selective contacts based on dopant free materials are receiving increased attention. Copper(I) sulfide (Cu2S), earth-abundant and non-toxic, shows potential for use in silicon (Si) solar cells, though its carrier selectivity mechanism remains unclear. We present a detailed investigation of the selectivity mechanisms behind thermally evapora...

We present a subnanometer scale study of the interface between crystalline silicon (c-Si) and aluminum oxide (AlO $_{x}$ ) deposited by an industrial type, remotely plasma-enhanced chemical vapor deposition (PECVD) system. We investigate the origin of the negative charge density within the AlO $_{x}$ layer and the interface defect density. In ord...

The interface of high-quality crystalline silicon/hydrogenated amorphous silicon (c-Si/a-Si:H) is indispensable for achieving the ideal conversion efficiency of Si heterojunction solar cells. Therefore, it is extremely desirable to characterize and control the interface at the atomic scale. Here, we employ spherical aberration-corrected transmissio...

Boron-doped Czochralski-grown silicon wafers dominate the photovoltaic market. Light-induced degradation of these wafers is one of the most significant roadblocks for high-efficiency solar cells. Despite a very large number of publications on this topic, only a few studies have directly investigated the precursor of the defect responsible for this...

The capture cross sections are a key metric to characterize carrier traps in semiconductors. In this article, photoconductance measurements are used to estimate the capture cross sections of traps that are induced by thermal donors in Czochralski-grown silicon wafers. Here, we use a pulse-filling technique with light-emitting diode excitation to me...

Characterization and identification of recombination active defects in photovoltaic (PV) materials are essential for improving the performance of solar cells, hence, reducing their levelized cost of electricity. Injection dependent lifetime spectroscopy (IDLS) is a sensitive and widely used technique for investigating defects in silicon. With the d...

The dissociation of FeB pairs in p‐type silicon under injection is often explained by the charge state change of interstitial Fe (Fei) from positive to neutral. It is also sometimes interpreted as a Recombination‐Enhanced Defect Reaction (REDR) mechanism. The charge effect and the REDR have fundamentally different impacts on the dissociation/associ...

A wide range of defects, failures, and degradation can develop at different stages in the lifetime of photovoltaic modules. To accurately assess their effect on the module performance, these failures need to be quantified. Electroluminescence (EL) imaging is a powerful diagnostic method, providing high spatial resolution images of solar cells and m...

The performance of solar cells influences the reliability, lifetime, cost, and safety of photovoltaic power plants. The electrical performance of these cells, as well as, their degradation rates over time, can vary between individual cells within the same photovoltaic module. Current–voltage measurements can provide detailed data on cell performanc...

The performance of high-efficiency silicon solar cells is limited by the presence of bulk defects. Identification of these defects has the potential to improve cell performance and reliability. The impact of bulk defects on minority carrier lifetime is commonly measured using temperature- and injection-dependent lifetime spectroscopy and the defect...

Float-zone (FZ) silicon is usually assumed to be bulk defect-lean and stable. However, recent studies have revealed that detrimental defects can be thermally activated in FZ silicon wafers and lead to a reduction of carrier lifetime by up to two orders of magnitude. A robust methodology which combines different characterization techniques and passi...

To keep improving the efficiency-to-cost ratio of photovoltaic solar cells, manufacturing lines must be continuously improved. Efficiency optimization is usually performed process-wise and can be slow and time-consuming. In this study, we propose a machine-learning-based method to perform simultaneous multiprocess optimization. Using the natural va...

Presents corrections to the above named paper.

In the majority of studies involving injection dependent lifetime spectroscopy, it is assumed that the investigated defect is a single-level defect following Shockley-Read-Hall recombination statistics. Nevertheless, in real life, two-level defects or multi-level defects are more common than single-level defects. In this study, we first investigate...

The anomalous optoelectronic properties of a quasi‐vertical orientated Chalcostibite CuSbS2 thin film synthesized on glass substrate are studied in detail. Two well‐separated absorption edges of CuSbS2 are identified by photothermal‐deflection spectroscopy (PDS) at 1.48 and 0.90 eV. The formation mechanism of the 0.9 eV infrared edge is found to be...

This study presents an injection dependent numerical model relating Shockley-Read-Hall defect parameters in crystalline silicon with the recombination parameter γ. We demonstrate how the model can be used to predict γ for various single level defects. Additionally, we show that γ can be significantly influenced by the injection level, in contrast t...

Sub-bandgap luminescence is characteristic of radiative transitions from defects in semiconductors. However, methods to extract defect-identifying parameters from this luminescence are lacking. Here, we present a method to extract these parameters from temperature- and intensity-dependent micro-photoluminescence (μPL) spectra. The initial “coarse”...

The cover image is based on the Applications Outdoor photoluminescence imaging of solar panels by contactless switching: Technical considerations and applications by Raghavi Bhoopathy al., https://doi.org/10.1002/pip.3216.