External Gettering of Metallic Impurities by Black Silicon Layer

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To improve the absorption of light in two‐junction tandem perovskite–silicon solar cells, antireflective textures are often created on the front surface in the form of micronsized pyramids using wet‐chemical etching. It is known that single‐junction silicon solar cells with nanotextured black silicon (BS) formed by dry‐etching techniques are more efficient than pyramidal microtextures. Herein, experimental evidence of enhanced efficiency of structures using BS between the perovskite layer and the silicon substrate for the first time is demonstrated. BS is fabricated using plasma‐based reactive‐ion etching on the front surface of the crystalline silicon. The deposition of mixed‐halide perovskite layers is performed by vacuum coevaporation and sequential evaporation. The structural and optical properties of evaporated perovskite layers with various thicknesses are investigated. It is found that the structural‐phase quality (viz., surface coverage, chemical composition, dimensionality, crystallinity, and phase purity) of perovskite layers on planar and nanotextured substrates is similar. However, the root mean square roughness of the perovskite layers on nanotextured substrates is much higher, which reduces the reflection significantly, especially, in the range of radiation incidence angle up to 60°. These results pave the way for the development of high‐performance perovskite–silicon tandem solar cells for improved efficiency.

Section: Resultsmentioning

confidence: 99%

Section: Structural Propertiesmentioning

confidence: 99%

Structural and Optical Properties of Vacuum‐Evaporated Mixed‐Halide Perovskite Layers on Nanotextured Black Silicon

Vaseashta

Ayvazyan

Khudaverdyan

et al. 2023

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“…nanostructured forms of crystalline Si are used in the production of semiconductor devices and integrated circuits for external gettering of structural defects, enhanced doping of impurities, as well as for the formation of layers sensitive to mechanical, light, and chemical influences. [27][28][29][30][31][32][33] PSi and BSi are especially intensively studied for use as antireflective frontal surfaces for single junction [34][35][36][37] and tandem [38][39][40] solar cells.…”

Section: Introductionmentioning

confidence: 99%

NO₂ Gas Sensor Based on Pristine Black Silicon Formed by Reactive Ion Etching

Ayvazyan

Hakhoyan

et al. 2023

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Nitrogen dioxide (NO2) is a serious environmental pollutant and can cause negative consequences on both human health and vegetation growth. Herein, the possibility and promise of using a resistive sensor based on pristine black silicon (BSi) to detect NO2 at room temperature are investigated. BSi is prepared using plasma‐based reactive ion etching. Scanning electron microscope (SEM) studies show that BSi consists of vertically standing nanoneedles and has a large surface area, which facilitates gas adsorption. The gas‐sensing properties of the BSi‐based sensor are tested for low NO2 concentrations (1–5 ppm). It is found that the prepared sensor samples without posttreatments of BSi exhibit high sensitivity, fast transient response, and good repeatability. In particular, the response and recovery time of the sensor are ≈35 and ≈25 s for 4 ppm NO2 gas exposure, respectively. Besides, the results indicate that the BSi‐based sensor has excellent selectivity. Finally, the sensing mechanism is discussed, the dominating factors of which are the large active sensing area and the vertical arrangement of the BSi nanoneedles. It is believed that with further optimization, BSi has good potential as a functional material for gas sensors.

“…[1][2][3] This material has high potential to be commercialized for various applications, including microelectronics, photovoltaics, and biochemical sensing. [4][5][6][7] Currently, BS layers are especially intensively studied for use as antireflective frontal surfaces for single junction solar cells [8][9][10][11] and antireflective interlayers for tandem solar cells. [12][13][14] However, the large area of BS contributes to an undesirable increase in the carrier recombination rate, which results in poor spectral characteristics, especially at short wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Properties of Black Silicon Layers Fabricated by Different Techniques for Solar Cell Applications

Ayvazyan,

Hakhoyan

et al. 2023

Self Cite

Black silicon (BS) layers coated with passivation films are widely used as antireflective frontal surfaces for solar cells. The most common BS fabrication techniques are reactive ion etching (RIE), metal‐assisted chemical etching, and laser‐induced processing. Herein, the structural and optical properties, as well as the minority carrier lifetime, of BS are compared with and without atomic layer deposited HfO2 passivation films produced by the above formation methods. The antireflection behavior of the samples is discussed based on the light trapping effect and the change in the BS refractive index from air to the bulk of crystalline Si. Finally, test solar cells are manufactured, and their photovoltaic parameters are studied. The comparison results show that RIE is the most preferred in all technical respects. The features of using different BS fabrication techniques from the solar cell manufacturing point of view are analyzed.