Controlling Unintentional Defects Enables High‐Efficient Antimony Selenide Solar Cells

Antimony selenide (Sb2Se3) solar cells often demonstrate current–voltage (J–V) distortion at low temperature, particularly at reverse bias or under red‐light irradiation. A highly doped p‐type (HDP) thin layer between the buffer and absorber layers is typically supposed to induce the J–V distortion. In this work, an analytical model for the experimental Sb2Se3 solar cell has been presented to investigate the effect of the HDP layer characteristics on the J–V distortion. This proposed model can also calculate the critical voltage at which the J–V distortion occurs. The results show that the Sb2Se3 solar cells with the HDP layer have low efficiency when doping concentration and thickness of the HDP layer increase due to a large J–V distortion. This study confirms that the presence of an electron barrier in the conduction band formed by the HDP layer can cause J–V distortion. Hence, the effect of electron barrier height on cell performance based on the derived formulas is investigated. Finally, comparing the simulation and modeling results with variations of the physical and electrical properties of the HDP layer provides a good evaluation for understanding the behavior of Sb2Se3 solar cells.

Investigations into novel device architectures and interfaces that enhance charge transport and collection are necessary to increase the power conversion efficiency (PCE) of antimony selenide (Sb2Se3) solar cells, which have shown great promise as a low-cost and high-efficiency alternative to conventional silicon-based solar cells. The current work uses device simulations to design p-i-n and n-i-p Sb2Se3-based solar cell structures. The n-i-p configuration is investigated by comparing distinct electron transport layer (ETL) materials to get the best performance. While certain ETL materials may yield higher efficiencies, the J–V curve may exhibit S-shaped behavior if there is a misalignment of the bands at the ETL/absorber interface. To address this issue, a proposed double ETL structure is introduced to achieve proper band alignment and conduction band offset for electron transport. A PCE of 20.15% was achieved utilizing (ZnO/ZnSe) as a double ETL and Spiro-OMeTAD as a hole transport layer (HTL). Further, the p-i-n configuration is designed by proposing a double HTL structure to facilitate hole transport and achieve a proper valence band offset. A double HTL consisting of (CuI/CuSCN) is used in conjunction with ETL-free configuration to achieve a PCE of 21.72%. The simulation study is conducted using the SCAPS-1D device simulator and is validated versus a previously fabricated cell based on the configuration FTO/CdS/Sb2Se3/Spiro-OMeTAD/Au.

Efficiency improvement of flexible Sb2Se3 solar cells with non-toxic buffer layer via interface engineering

Vanadium-doped indium tin oxide window layer in Sb2Se3 solar cell

Antimony selenide (Sb2Se3) is emerging as a promising photovoltaic material owing to its excellent photoelectric property. However, the low carrier transport efficiency, and detrimental surface oxidation of the Sb2Se3 thin film greatly influenced the further improvement of the device efficiency. In this study, the introduction of tellurium (Te) can induce the benign growth orientation and the desirable Sb/Se atomic ratio in the Te-Sb2Se3 thin film. Under various characterizations, it found that the Te-doping tended to form Sb2Te3-doped Sb2Se3, instead of alloy-type Sb2(Se,Te)3. After Te doping, the mitigation of surface oxidation has been confirmed by the Raman spectra. High-quality Te-Sb2Se3 thin films with preferred [hk1] orientation, large grain size, and low defect density can be successfully prepared. Consequently, a 7.61% efficiency Sb2Se3 solar cell has been achieved with a VOC of 474 mV, a JSC of 25.88 mA/cm2, and an FF of 64.09%. This work can provide an effective strategy for optimizing the physical properties of the Sb2Se3 absorber, and therefore the further efficiency improvement of the Sb2Se3 solar cells.

Antimony triselenide (Sb2 Se3 ) has possessed excellent optoelectronic properties and has gained interest as a light-harvesting material for photovoltaic technology over the past several years. However, the severe interfacial and bulk recombination obviously contribute to significant carrier transport loss thus leading to the deterioration of power conversion efficiency (PCE). In this work, buried interface and heterojunction engineering are synergistically employed to regulate the film growth kinetic and optimize the band alignment. Through this approach, the orientation of the precursor films is successfully controlled, promoting the preferred orientational growth of the (hk1) of the Sb2 Se3 films. Besides, interfacial trap-assisted nonradiative recombination loss and heterojunction band alignment are successfully minimized and optimized. As a result, the champion device presents a PCE of 9.24% with short-circuit density (JSC ) and fill factor (FF) of 29.47mA cm-2 and 63.65%, respectively, representing the highest efficiency in sputtered-derived Sb2 Se3 solar cells. This work provides an insightful prescription for fabricating high-quality Sb2 Se3 thin film and enhancing the performance of Sb2 Se3 solar cells.

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

Optically addressable point defects in semiconductor materials have been identified as promising single-photon sources and spin qubits in quantum information technologies. The traditional method of exploring the optical and spin properties of these defects is using a laser with a wavelength shorter than the point defects’ zero-phonon-line (ZPL) to Stokes exciting and detecting the Stokes photoluminescence (PL). On the other hand, anti-Stokes excitation with the pumping laser’s wavelength longer than the defects’ ZPL can also be used to investigate their optical and spin properties. The anti-Stokes excitation has shown many advantages and attracted great interest. Here, we provide a brief review of the anti-Stokes excitation of optically active point defects in semiconductor materials. The Stokes and anti-Stokes PL spectra of different point defect systems in semiconductor materials are compared. We then discuss the main mechanisms of the anti-Stokes excitation of different physical systems and conclude that the anti-Stokes excitation of the point defect system in the semiconductor is a single-photon absorption phonon-assisted process. Finally, we summarize some practical applications of anti-Stokes excitation, including laser cooling of semiconductor materials, high-sensitivity quantum thermometry, and enhancement of the readout signal contrast of the point defect spin states. The anti-Stokes excitation of point defects in semiconductors extends the boundary of quantum technologies.

Advancing photocatalytic performance for enhanced visible-light-driven H2 evolution and Cr (VI) reduction of g-C3N4 through defect engineering via electron beam irradiation

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Semiconducting behavior of substitutionally doped bilayer graphene

A simulation procedure for observation of dislocation images in single-crystal silicon samples of

A complex of metrological, diagnostic, and technological support of investigations and innovations in the field of nanotechnologies based on the Nanostructures joint service center is presented. Results of the study of the atomic structure of the surface, interfaces, and structural defects in semiconductor materials; the development of modern electron and scanning probe microscopy methods; and the fabrication of low-dimensional solid-state systems for nanoelectronics are reviewed. The emphasis is on the development of physicochemical fundamentals of the nanostructuring of semiconductor materials, analysis of the main features of growth and defect formation in low-dimensional systems, and the fabrication of experimental elements of nanoelectronics for studying quantum, electron interference, and single-electron effects. The results provide the basis of nanotechnologies for controlled synthesis of nanostructures with tailored configurations and the required electrical, mechanical, and other properties.

One of the limitations of online quality control processes is the inability of detecting electronic defects in semiconductor materials. This is particularly important in low cost processes such as electrodeposited Cu(In,Ga)(S,Se) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> solar cells, due to the large number of inhomogeneities that can be expected. Standard techniques for characterizing electronic defects are not suitable for online control. However, optical techniques such as Raman scattering can be specially suited for online process monitoring applications. In this paper we analyze the correlation between the Raman spectral features and the presence of electronic defects. Our results confirm the potential of Raman spectroscopy for the indirect detection of point defects which are important for device performance.

A simple model tests the effect on ice-core impurity concentrations of climate-induced changes in the physical conditions of the atmosphere influencing transport and deposition processes, while keeping source areas and production rates constant. The model results show that the increased glacial concentrations observed for most impurities can be explained entirely by changes in transport and deposition. No increase in source emission is necessary, however possible, to explain the ten-fold increase in impurity concentrations during the Last Glacial Maximum. This shows that the effect of dynamic changes in the atmosphere can be large and has to be taken into account before translating deposition records into emission records. The total impurity content in the global atmosphere during the glacial period was higher if dynamic changes in the atmosphere rather than source-emission changes were responsible for the variations observed in polar areas. This implies that a climate-forcing mechanism is to be found in the dynamics of the atmosphere, since the radiative properties of the atmosphere depend on the total content of impurities in the atmosphere. The effect on the climate can probably be compared with, although opposite in sign to, the present-day anthropogenic greenhouse forcing.