Efficiency Of Silicon Solar Cells Research Articles

Enhancing power conversion efficiency of polycrystalline silicon solar cells through ZnO/SiO2/Al2O3 anti-reflective coatings via spin coating

The investigation aims to enhance the photocurrent generation of p-Si solar cells through the application of anti-reflective coatings (ARC) including ZnO, SiO2, Al2O3, and a combination of ZnO, SiO2, and Al2O3. The spin coating approach was preferred for depositing anti-reflective coating materials as clear thin films on the substrate of the p-Si cells. The absorbance, reflectance, I-V, morphology, and temperature behaviour of the ARCs onp-Si cells were examined to ascertain the impact of the ARCs. Among several coating materials, the blended ZnO+SiO2+Al2O3on p-Si cells achieved a highest conversion efficiency of 20.71% under controlled setup condition, with anelectrical resistance of5.83×10-3 Ω cm. The examination of the optical characteristics demonstrated a highestabsorbance of 92% and a lowest reflection loss of 10%, attained by the ZnO+SiO2+Al2O3sample within UV band. The ZnO+SiO2+Al2O3 blend exhibited significant enhancement in thermal behaviour, achieving a lowest temperature of 49.9 °C in controlled source settings. Analyses demonstrated that the composite ZnO+SiO2+Al2O3 is a suitable blendwithanideal anti-reflectiveproperties to improve the efficiency of p-Si solar panels.

Mo-doped vanadium oxide for p-type silicon solar cells with an improved hole selective contact

Abstract As a typical transition metal oxide with high work function, vanadium oxide (V2O5) is a very promising hole selective layer for efficient crystalline silicon (c-Si) solar cells. The holes are extracted or transported via band-to-band tunneling and trap-assisted tunneling (TAT), which strongly depend on the concentration of oxygen vacancies (V O); however, very little work has focused on its effective modulation. Herein, solution-processed V2O5 films are doped with Mo6+ to tune the hole selectivity for p-Si heterojunction solar cells. With an appropriate doping concentration of 10 mol%, the surface passivation is improved and the contact resistivity decreases simultaneously. The enhanced hole-selective transport with the dominated TAT mechanism contributes to the photoelectric conversion efficiency (PCE) of V2O5/p-Si heterojunction solar cells being increased from 16.2% to 17.7%, due to the increase of V O induced by the electron transfer from Mo6+ to V5+. The utilization of forming gas annealing further improves the PCE up to 18.2%, ascribed to the generation of more V O and the additional passivation of hydrogen, which is the highest achieved with solution-processed V2O5−X for c-Si heterojunction solar cells up to now.

Triplet Exciton Sensitization of Silicon Mediated by Defect States in Hafnium Oxynitride.

Singlet exciton fission has the potential to increase the efficiency of crystalline silicon solar cells beyond the conventional single junction limit. Perhaps the largest obstacle to achieving this enhancement is uncertainty about energy coupling mechanisms at the interfaces between silicon and exciton fission materials such as tetracene. Here, the previously reported silicon-hafnium oxynitride-tetracene structure is studied and a combination of magnetic-field-dependent silicon photoluminescence measurements and density functional theory calculations is used to probe the influence of the interlayer composition on the triplet transfer process across the hafnium oxynitride interlayer. It is found that hafnium oxide interlayers do not show triplet exciton sensitization of silicon, and that nitrogen content in hafnium oxynitride layers is correlated with enhanced sensitization. Calculation results reveal that defects in hafnium oxynitride interlayers with higher nitrogen content introduce states close to the band-edge of silicon, which can mediate the triplet exciton transfer process. Some defects introduce additional deleterious mid-gap states, which may explain observed silicon photoluminescence quenching. These results show that band-edge states can mediate the triplet exciton transfer process, potentially through a sequential charge transfer mechanism.

Vacancy Defect Regulation in Copper(I) Thiocyanate Hole Selective Layer for Efficient and Stable Crystalline Silicon Solar Cells

Vacancy Defect Regulation in Copper(I) Thiocyanate Hole Selective Layer for Efficient and Stable Crystalline Silicon Solar Cells

Theoretical study of the solution of the diffusion equation under effect of the magnetic field on the silicon solar cell

PurposeThe purpose of this study is to investigate the behavior of a silicon solar cell when subjected to a magnetic field. Specifically, the study aims to understand how the presence of the magnetic field influences the distribution of excess minority carriers within the base region of the solar cell. By solving the one-dimensional continuity equation under these conditions, the study seeks to elucidate the transient dynamics of carrier generation, recombination and transport processes. This research contributes to the broader understanding of how external magnetic fields can impact the performance and efficiency of silicon solar cells, potentially informing future optimizations or applications in photovoltaic technology.Design/methodology/approachThe solar cell is assumed to be uniformly illuminated, which simplifies the analysis of carrier generation to a function of depth (x). The emitter and space charge region contributions are considered while neglecting the diffusion region. The injection level remains constant throughout the analysis, focusing specifically on the base thickness region, H = 200 µm.FindingsThe findings of this study reveal significant insights into the behavior of a silicon solar cell under the influence of a magnetic field. Key findings include Impact on carrier distribution: the magnetic field affects the distribution of excess minority carriers within the base region of the solar cell. This distribution is crucial for understanding the efficiency of carrier collection and overall cell performance. Transient dynamics: the transient behavior of carrier generation, recombination and transport processes in the base region is influenced by the magnetic field. This understanding helps in predicting the response time and effectiveness of the solar cell under varying magnetic field strengths. Optimization potential: insights gained from this study suggest potential strategies for optimizing the design and operation of silicon solar cells to enhance their performance in environments where magnetic fields are present. Theoretical framework: the study provides a theoretical framework based on the one-dimensional continuity equation, offering a systematic approach to analyzing and predicting the behavior of solar cells under magnetic field conditions. These findings contribute to advancing the understanding of how external factors such as magnetic fields can impact the operation and efficiency of silicon solar cells, thereby guiding future research and development efforts in photovoltaic technology.Originality/valueThe originality and value of this study lie in its contribution to advancing the understanding of how magnetic fields influence silicon solar cell performance, providing both theoretical insights and potential practical applications in diverse technological contexts.

Study of Aluminium, Gallium and Gallium Boron as P-Type Dopants for New-Generation n+np+ Solar Cells

Silicon n-type n+np+ solar cells offer many advantages over conventional n+pp+ cells, including better resistance to light-induced degradation and higher conversion efficiency potential. However, the formation of the p+ emitter in n+np+ cells requires high diffusion temperatures and the use of alternative boron dopants is necessary to overcome the limitations of conventional processes. This study explored aluminium, gallium and gallium/boron co-doping as p-type dopants for the fabrication of thin (140 µm) n+np+ solar cells. The results showed that aluminium is not suitable for the formation of the p+ emitter due to its low solid solubility in silicon and its high segregation towards silicon oxide. Gallium required high diffusion temperatures and suffered from a degradation of the concentration profile in later stages of the manufacturing process, leading to poor performing solar cells. Gallium/boron co-doping has proved to be a promising alternative to boron. Thin n+np+ solar cells doped with GaB achieved a maximum conversion efficiency of 13.7%, slightly lower than that of boron-doped cells (14.9%). Optimisation of the GaB diffusion process and surface passivation could further improve the performance of these cells. This study demonstrates the potential of gallium/boron co-doping for the manufacture of new-generation thin n+np+ solar cells. Further research is needed to fully exploit the advantages of this technology and contribute to improving the efficiency and cost of silicon solar cells.

Efficient Silicon Solar Cells with Aluminum‐Doped Zinc Oxide‐Based Passivating Contact

AbstractCrystalline silicon (c‐Si) solar cells require passivating contacts to unlock their full efficiency potential. For this doped silicon layers are the materials of choice, as they yield device voltages close to the thermodynamic limit. Yet, replacing such layers with wide‐bandgap metal oxides may be advantageous from a cost perspective and minimize parasitic optical absorption. Here the aluminum‐doped zinc oxide (AZO)‐based passivating contacts with high electron selectivity are presented. The SiO2/AZO/Al2O3 stack is demonstrated to provide excellent surface passivation on c‐Si (implied Voc up to 742 mV) after thermal annealing, and an average contact resistivity of 51 mΩ cm2 is simultaneously obtained after etching off Al2O3 capping layer. By the implementation of AZO‐based electron‐selective contact, a champion power conversion efficiency (PCE) of 24.3% is achieved on c‐Si solar cells, representing the PCE record for metal oxide‐based passivating contacts. Finally, the efficiency potential, cost, and industrial compatibility of the AZO‐based electron‐selective contacts are discussed, paving the way for industrial applications.

Light-trapping by wave interference in intermediate-thickness silicon solar cells.

The power conversion efficiency of crystalline silicon (c - Si) solar cells have witnessed a 2.1% increase over the last 25 years due to improved carrier transport. Recently, the conversion efficiency of c - Si cell has reached 27.1% but falls well below the Shockley-Queisser limit as well as the statistical ray-optics based 29.43% limit. Further improvement of conversion efficiency requires reconsideration of traditional ray-trapping strategies for sunlight absorption. Wave-interference based light-trapping in photonic crystals (PhC) provides the opportunity to break the ray-optics based 4n2 limit and offers the possibility of conversion efficiencies beyond 29.43% in c - Si cells. Using finite difference time domain simulations of Maxwell's equations, we demonstrate photo-current densities above the 4n2 limit in 50 - 300µm-thick inverted pyramid silicon PhCs, with lattice constant 3.1µm. Our 150µm-thick PhC design yields a maximum achievable photo-current density (MAPD) of 45.22mA/cm2. We consider anti-reflection coatings and surface passivation consisting of SiO2 - SiNx - Al2O3 stacks. Our design optimization shows that a 80 - 120 - 150nm stack leads to slightly better solar light trapping in photonic crystal cells with thicknesses <50µm, whereas the 80 - 40 - 20nm stack performs better for cells with thicknesses >100µm. We show that replacing SiNx with SiC may improve the MAPD for PhC cells thinner than 100µm. For a fixed lattice constant of 3.1µm, we find no significant improvement in the solar absorption for 50 and 100µm-thick cells relative to a 15µm cell. A substantial improvement in the MAPD is observed for the 150µm cell, but there is practically no improvement in the solar light absorption beyond 150µm thickness.

Transparent Hole‐Selective Molybdenum Oxide Passivating Contact with Chlorine‐Based Interlayer Enabling 22.5% Efficient Silicon Solar Cells

The need to increase transparency in existing passivating contacts for crystalline silicon solar cells has motivated the development of transparent contacts based on transition metal oxides (TMOs). Among hole‐selective materials, molybdenum oxide (MoOx) has achieved the greatest success so far. However, despite providing low contact resistivity, MoOx relies on an intrinsic hydrogenated amorphous silicon (a‐Si:H(i)) interlayer to achieve high levels of surface passivation and thus high open‐circuit voltage at a device level, partially defeating the objective of improved transparency. Herein, we report unprecedented performance for a‐Si:H‐free MoOx‐based contacts by employing an alternative passivating interlayer based on a well‐engineered chlorine‐containing Al‐alloyed titanium oxide/titanium dioxide (AlyTiOx/TiO2 )stack. The resulting AlyTiOx/TiO2/MoOx stack achieved record levels of passivation, reaching J0 values as low as 16 fA cm−2, closer to values reported for a‐Si:H‐based contacts, while maintaining lower contact resistivity, well below 100 mΩ cm−2. Additionally, the stack presents improved transparency compared to a‐Si:H‐based contacts, with gains in short‐circuit current density of at least 0.8 mA cm−2. The work pushes the performance of hole‐selective passivating contacts based on TMOs to new levels, enabling a record efficiency of 22.53% for cells with fully transparent hole‐selective passivating contacts. This work serves as an important stepping stone toward low‐thermal‐budget, simple manufacturing of high‐efficiency solar cells.

Host sensitized down conversion emission in KSrVO4:Yb3+− A potential thermally stable phosphor for solar cell applications

This work reports the successful synthesis of an efficient near infra-red (NIR) emitting KSrVO4:Yb3+ phosphor using the combustion method. The X-ray diffraction technique (XRD) confirmed the orthorhombic phase of a material whereas X-ray photoelectron spectroscopy (XPS) analyzed the elemental makeup and chemical states of the phosphor components. Photoluminescence (PL) analysis revealed that the phosphor exhibit superior thermal stability and emit in the NIR region when activated by near-UV light. An upsurge in emission intensity occurs upon the incorporation of Bi3+ as a co-dopant. Using diffuse reflectance spectra (DRS), optical band gap, metallization constant, and refractive index were computed for all ion concentrations in KSr(1-x)VO4:xYb3+ (0 ≤x ≤ 0.06). For the optimized concentration of Yb3+ into the host, numerical values of these parameters were also estimated. The studies reveal that the produced material may be applied as a solar spectrum converter to improve the efficiency of crystalline silicon (c-Si) solar cells.

Fabrication of zinc oxide and phosphorus optical thin films and comparison of their effect on silicon solar cell efficiency

Fabrication of zinc oxide and phosphorus optical thin films and comparison of their effect on silicon solar cell efficiency

The impact of interface recombination on the external quantum efficiency of silicon solar cells

In various types of organic/inorganic solar cells, optical response enhancement is consistently observed within the external quantum efficiency spectra owing to the improvement in interface passivation and the suppression of carrier recombination. In this study, we focused on crystalline silicon solar cells and systematically investigated the impact of interface recombination on the optical response upon dual-side illumination using numerical simulations. The results shed light on the interesting phenomenon that the surface recombination velocity has a significant impact on the external quantum efficiency, and it changes as the illumination direction changes. Moreover, from a practical perspective, the spectra of external quantum efficiency under dual-side illumination conditions can act as a powerful tool for the quick diagnosis of the passivation quality at the top and bottom interfaces.

An experimental investigation of spin-on doping optimization for enhanced electrical characteristics in silicon homojunction solar cells: Proof of concept

The pursuit of enhancing the performance of silicon-based solar cells is pivotal for the progression of solar photovoltaics as the most potential renewable energy technologies. Despite the existence of sophisticated methods like diffusion and ion implantation for doping phosphorus into p-type silicon wafers in the semiconductor industry, there is a compelling need to research spin-on doping techniques, especially in the context of tandem devices, where fabricating the bottom cell demands meticulous control over conditions. The primary challenge with existing silicon cell fabrication methods lies in their complexity, cost, and environmental concerns. Thus, this research focuses on the optimization of parameters, such as, deposition of the spin on doping layer, emitter thickness (Xj), and dopant concentration (ND) to maximize solar cell efficiency. We utilized both fabrication and simulation techniques to delve into these factors. Employing silicon wafer thickness of 625 μm, the study explored the effects of altering the count of dopant layers through the spin-on dopant (SOD) technique in the device fabrication. Interestingly, the increase of the dopant layers from 1 to 4 enhances efficiency, whereby, further addition of 6 and 8 layers worsens both series and shunt resistances, affecting the solar cell performance. The peak efficiency of 11.75 % achieved in fabrication of 4 layers dopant. By using device simulation with wxAMPS to perform a combinatorial analysis of Xj and ND, we further identified the optimal conditions for an emitter to achieve peak performance. Altering Xj between 0.05 μm and 10 μm and adjusting ND from 1e+15 cm−3 to 9e+15 cm−3, we found that maximum efficiency of 14.18 % was attained for Xj = 1 μm and ND = 9e+15 cm−3. This research addresses a crucial knowledge gap, providing insights for creating more efficient, cost-effective, and flexible silicon solar cells, thereby enhancing their viability as a sustainable energy source.

Theoretical Analysis and Simulation of SiO2 and ZrO2 Based Antireflective Coatings to Improve Crystalline Silicon Solar Cell Efficiency

The Solar cell efficiency is crucial, and optical losses can hinder it significantly. Anti-reflective coatings are effective in minimizing these losses. In our study, we used Fresnel equations to calculate reflectance values for single-layer SiO2, ZrO2, a SiO2-ZrO2 mixture, and a double-layer SiO2/ZrO2 configuration. We then assessed their impact on crystalline silicon solar cells using the SCAPS program. The reflectance values of single-layer SiO2, ZrO2 and 10%SiO2-90%ZrO2 mixture were calculated as 19.17%, 13.09% and 13.01%, respectively. Notably, the double-layer SiO2/ZrO2 coating showed a low reflectance of 7.58%, a significant improvement compared to uncoated silicon at 37.45%. Efficiency values for crystalline silicon solar cells were calculated for single layer as 18,95% (SiO2), 20.39% (ZrO2), 20,40% (mixed coating) respectively and 21.68% for the double-layer SiO2/ZrO2 configuration.

Optimizing thin-film silicon solar cells with nanostructured TiO2 and a silver back reflector for enhanced energy conversion efficiency

This paper investigates the improvement of energy conversion efficiency in thin-film silicon solar cells by employing periodic nanostructures of TiO2 on the silicon active layer and a back reflector featuring periodic nanostructures of silver. The objective is to increase the optical path length, enhance absorption probability for longer wavelengths, and subsequently improve solar cell performance. Three silicon-based solar cell configurations are proposed and simulated using the finite difference time domain (FDTD) method to assess their performance. Electrical characteristics are obtained through the drift-diffusion method. The resulting short-circuit current density increased from 40.93 to 65.28 to 95.373mA/cm2 for the three cells, leading to significant improvements in conversion efficiency with observed values of 20.39%, 33.26%, and 47.28%, respectively, in the optimized structures. Furthermore, we compare the simulation results of the three structures with those of a reference structure and several structures previously proposed in the literature.

Enhanced Efficiency of Silicon Solar Cell by New Salophen Complexes Embedded PMMA as Light Concentrators

The Schiff base N,N-bis(salicylidene)-o-phenylenediamine (salophen) was prepared by the condensation of salicylaldehyde with o-phenylenediamine in ethanol solution. Two new Zn(II) and Ni(II) salophen complexes, were synthesized, fully characterized by infrared (IR), 1H NMR spectroscopic measurements, UV–Vis spectra, photoluminescence (PL), and X-ray diffraction (XRD). The prepared complexes were used as phosphors to fabricate complexes/PMMA slab-based luminescent solar concentrators (LSC). The thermal stability of pure and doped PMMA polymer was examined by differential scanning calorimetry. Various parameters such as the optical energy gap, refractive index, AC and DC conductivity, dielectric constant, dielectric loss, Urbach energy, fluorescence quantum yield, and Stokes shift have been calculated and discussed. Optical absorption is carried out in wavelength region 200–900 nm at room temperature before and after the samples have been exposed to sunlight for up to 8 h. Photodegradation studies showed that the Zn(II) complex/PMMA LSC has the lowest rate of degradation compared with Ni(II) complex/PMMA LSC with the same concentration (0.06% weight). I–V characteristics of the photovoltaic devices with and without collectors were examined. The PV cell coupled with LSC shows an increase in maximum efficiency by about 50% compared to the normal one. This indicates that the proposed technique is very useful for improving the efficiency of solar cells.

ZnS-coated Yb3+-doped perovskite quantum dots: A stable and efficient quantum cutting photon energy converter for silicon-based electronics

Yb3+ doped lead halide perovskite quantum dots (PeQDs) with efficient quantum cutting emission are thought to be the most promising photon energy converter for improving the performance of silicon-based electronics. Nevertheless, the low external quantum efficiency (EQE) and instability make it unfeasible for industrial use. Here, we present a unique PeQDs@ ZnS core–shell device that achieves outstanding stability and up to 39 % EQE by effectively controlling energy transfer from the PeQDs to the Yb3+ through ZnS coating. These advances are attributed to the large UV absorption and the strong localized effect of the ZnS shells on the conduction band electrons of the PeQDs. Density functional theory (DFT) first-principles simulations indicate that ZnS coating can facilitate the energy transfer of PeQDs to Yb3+. Power conversion efficiency (PCE) of silicon solar cells was significantly enhanced by ZnS-coated Yb3+ doped PeQDs, yielding a noteworthy 13.5 % relative PCE improvement over 30 measurement sets. Significantly, the stability of SSCs with ZnS-coated PeQDs films is considerably improved, resulting in a capped device T80 lifespan of up to 11,224 h. Moreover, ZnS-coated PeQDs films can significantly boost the EQE of silicon photodiodes (Si-PDs) and extend their response to deep ultraviolet light. This paper presents an efficient and consistently stable photon energy converter with great commercialization potential.

Study of NIR long afterglow luminescent materials are used in silicon solar cells to produce electricity under dark condition

It is well known that the silicon solar cells can realize effective photoelectric conversion only under sunlight irradiation, and that can not generate electricity under dark condition. Thus, the effective working (photoelectric conversion) time of silicon solar cells throughout the whole day is very limited. In this paper, the up-conversion NIR long afterglow luminescent materials, Zn3Ga2-x-y-zGe2O10:xCr3+,yYb3+,zEr3+, were successfully prepared through high temperature calcination method. The structure, morphology, elemental composition and optical property of the prepared samples were analyzed by a series of characterization methods. In addition, the mechanisms of afterglow luminescent of these materials and the energy transfer mechanisms of up-conversion luminescent between the luminescent center Cr3+ and sensitizer ions (Yb3+ and Er3+) are discussed, respectively. Finally, the prepared luminescent materials are fixed on glass sheets with reflective capacity, and then are integrated with silicon solar cells in the form of a cover plate. And then, under dark conditions, the current density-voltage (J-V) curves and current density-time (J-T) curves of these silicon solar cells were tested to explore the influences of doping proportions of Cr3+, Yb3+, Er3+, Yb3+-Er3+ pairs and the calcination temperatures of Zn3Ga2-xGe2O10:xCr3+ on the power generation of the silicon solar cells. The results show that the photovoltaic conversion instantaneous efficiency of silicon solar cell with Zn3Ga1.975Ge2O10:1.0Cr3+,1.0 Yb3+,0.5Er3+ reaches the maximum value of 2.549 % under dark condition. The average efficiency within 300 s is 0.238%. At the same time, the silicon solar cell can generate dark current for up to 8.0 h, whose maximum dark current density and open-circuit voltage of 4.88 μA/cm2 and 0.914 mV, respectively. It is hoped that this study can provide some new ideas for silicon solar cells to generate electricity without sunlight irradiation.

Silicon solar cell efficiency improvement employing electrostatically assembled polyelectrolyte–quantum dot multilayers

Down-shifting (DS) has proven to be an effective technique to address thermalization losses in photovoltaic devices. It involves the modification of the incident solar spectrum by luminescent species to better suit solar cell’s optimal absorption regions. Despite the number of favorable characteristics of quantum dots (QDs) as DS materials, their incorporation into highly ordered close-packed films remains the major drawback of QD-based DS applications. This limitation can be overcome by the sequential integration of QDs into a multilayered film via the layer-by-layer assembly technique, that allows the precise control of composition and thickness. The experimental results discussed herein indicate that upon optimization employing a model-assisted design approach, the spectral response of a silicon solar cell benefits from the down-shifting and antireflection capabilities of the QD film, as evinced by their quantum efficiency. For the optimum design, the incorporation of QDs triggered an increment of 26.1% in the power conversion efficiency driven by an increase of 29.2% in the short circuit current density. The controlled assembly of QD multilayers offers unique opportunities in light harvesting for new hybrid photovoltaic technologies.

Space charge region recombination in highly efficient silicon solar cells

The recombination rate in the space charge region (SCR) of a silicon-based barrier structure with a long Shockley–Reed–Hall lifetime is calculated theoretically by taking into account the concentration gradient of excess electron-hole pairs in the base region. Effects of the SCR lifetime and applied voltage on the structure ideality factor have been analyzed. The ideality factor is significantly reduced by the concentration gradient of electron-hole pairs. This mechanism provides an increase of the effective lifetime compared to the case when it is insignificant, which is realized at sufficiently low pair concentrations. The theoretical results have been shown to be in agreement with experimental data. A method of finding the experimental recombination rate in SCR in highly efficient silicon solar cells (SCs) has been proposed and implemented. It has been shown that at the high excess carrier concentration exceeding 1015 cm–3 the contribution to the SCR recombination velocity from the initial region of SCR that became neutral is significant. From a comparison of theory with experiment, the SCR lifetime and the ratio of the hole to the electron capture cross sections are determined for a number of silicon SCs. The effect of SCR recombination on the key characteristics of highly efficient silicon SCs, such as photoconversion efficiency and open-circuit voltage, has been evaluated. It has been shown that they depend not only on the charge carrier lifetime in SCR, but also on the ratio of hole to electron capture cross sections σp /σn. When σp /σn &lt; 1, this effect is significantly strengthened, while in the opposite case σp /σn &gt; 1 it is weakened. It has been ascertained that in a number of highly efficient silicon SCs, the distribution of the inverse lifetime in SCR is described by the Gaussian one. The effect described in the paper is also significant for silicon diodes with a thin base, p-i-n structures, and for silicon transistors with p-n junctions. In Appendix 2, the need to take into account the lifetime of non-radiative excitonic Auger recombination with participation of deep impurities in silicon is analyzed in detail. It has been shown, in particular, that considering it enables to reconcile the theoretical and experimental dependences for the effective lifetime in the silicon bulk.