In this work,we developed a simple and direct circuit model with a dual two-diode model that can be solved by a SPICE numerical simulation to comprehensively describe the monolithic perovskite/crystalline silicon(PVS/...In this work,we developed a simple and direct circuit model with a dual two-diode model that can be solved by a SPICE numerical simulation to comprehensively describe the monolithic perovskite/crystalline silicon(PVS/c-Si)tandem solar cells.We are able to reveal the effects of different efficiency-loss mechanisms based on the illuminated current density-voltage(J-V),semi-log dark J-V,and local ideality factor(m-V)curves.The effects of the individual efficiency-loss mechanism on the tandem cell’s efficiency are discussed,including the exp(V/VT)and exp(V/2VT)recombination,the whole cell’s and subcell’s shunts,and the Ohmic-contact or Schottky-contact of the intermediate junction.We can also fit a practical J-V curve and find a specific group of parameters by the trial-and-error method.Although the fitted parameters are not a unique solution,they are valuable clues for identifying the efficiency loss with the aid of the cell’s structure and experimental processes.This method can also serve as an open platform for analyzing other tandem solar cells by substituting the corresponding circuit models.In summary,we developed a simple and effective methodology to diagnose the efficiency-loss source of a monolithic PVS/c-Si tandem cell,which is helpful to researchers who wish to adopt the proper approaches to improve their solar cells.展开更多
We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction st...We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.展开更多
Solar cells are now widely used as a clean method for electric energy generation. Among various type of solar cells, we compared the ability between amorphous and tandem (amorphous and polycrystalline) silicon solar c...Solar cells are now widely used as a clean method for electric energy generation. Among various type of solar cells, we compared the ability between amorphous and tandem (amorphous and polycrystalline) silicon solar cells by means of simultaneous running test. This kind of comparison is of importance practically, because the comparison of only inherent characteristics cannot include environmental parameters such as temperature totally. It was concluded that both types of solar cells provided almost the same energy for one year. The amorphous silicon solar cell provided more energy in summer while the tandem solar cell was advantageous in winter. It is due to the fact that the decrease in energy conversion at the higher cell temperature is more noticeable in tandem solar cells.展开更多
This paper identifies the contributions of p-a-SiC:H layers and i-a-Si:H layers to the open circuit voltage of p-i-n type a-Si:H solar cells deposited at a low temperature of 125℃. We find that poor quality p-a-Si...This paper identifies the contributions of p-a-SiC:H layers and i-a-Si:H layers to the open circuit voltage of p-i-n type a-Si:H solar cells deposited at a low temperature of 125℃. We find that poor quality p-a-SiC:H films under regular conditions lead to a restriction of open circuit voltage although the band gap of the i-layer varies widely. A significant improvement in open circuit voltage has been obtained by using high quality p-~SiC:H films optimized at the "low-power regime" under low silane flow rates and high hydrogen dilution conditions.展开更多
This paper studies boron contamination at the interface between the p and i layers of μc-Si:H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary ...This paper studies boron contamination at the interface between the p and i layers of μc-Si:H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary Ion Mass Spectroscopy. It is found that the mixed-phase μc-Si:H materials with 40% crystalline volume fraction is easy to be affected by the residual boron in the reactor. The experimental results showed that a 500-nm thick μc-Si:H covering layer or a 30-seconds of hydrogen plasma treatment can effectively reduce the boron contamination at the p/i interface. However, from viewpoint of cost reduction, the hydrogen plasma treatment is desirable for solar cell manufacture because the substrate is not moved during the hydrogen plasma treatment.展开更多
This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si:H or μc...This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si:H or μc-Si:H covering layer between solar cells. Their effectiveness for the pretreatment is evaluated by means of phosphorus concentration in films, the dark conductivity of p-layer properties and cell performance.展开更多
This paper reports that high-rate-deposition of microcrystalline silicon solar cells was performed by very-highfrequency plasma-enhanced chemical vapor deposition. These solar cells, whose intrinsic μc-Si:H layers w...This paper reports that high-rate-deposition of microcrystalline silicon solar cells was performed by very-highfrequency plasma-enhanced chemical vapor deposition. These solar cells, whose intrinsic μc-Si:H layers were prepared by using a different total gas flow rate (Ftotal), behave much differently in performance, although their intrinsic layers have similar crystalline volume fraction, opto-electronic properties and a deposition rate of - 1.0 nm/s. The influence of Ftotal on the micro-structural properties was analyzed by Raman and Fourier transformed infrared measurements. The results showed that the vertical uniformity and the compact degree of μc-Si:H thin films were improved with increasing Ftotal. The variation of the microstructure was regarded as the main reason for the difference of the J V parameters. Combined with optical emission spectroscopy, we found that the gas temperature plays an important role in determining the microstructure of thin films. With Ftotal of 300 sccm, a conversion efficiency of 8.11% has been obtained for the intrinsic layer deposited at 8.5 A/s (1 A=0.1 nm).展开更多
A series of samples deposited by VHF-PECVD at different pressures were studied.The measurement results of photosensitivity (photo conductivity/dark conductivity) and activation energy indicated near the same rule with...A series of samples deposited by VHF-PECVD at different pressures were studied.The measurement results of photosensitivity (photo conductivity/dark conductivity) and activation energy indicated near the same rule with the change of the pressure.The results measured by Raman scattering spectra,X-ray diffraction and FTIR all proved the evident crystallization of the materials.Treating the p/i interface by hydrogen has a great improving effect on the performance of the microcrystalline silicon (μc-Si) p-i-n solar cells if the treatment time was appropriate.An efficiency of 4.24% for μc-Si p-i-n solar cells deposited by VHF-PECVD was firstly obtained.展开更多
In order to improve the efficiency of solar cells based on cubic silicon carbide (3C-SiC), one heterojunction solar cell and two tandem structures were simulated under AM1.5 illumination using SCAPS software. The cell...In order to improve the efficiency of solar cells based on cubic silicon carbide (3C-SiC), one heterojunction solar cell and two tandem structures were simulated under AM1.5 illumination using SCAPS software. The cells’ performances were studied according to the thickness of the silicon carbide layers. Simulation results allowed to achieve an efficiency of 22.03% with a tandem junction structure using an optimal thickness of 3C-SiC layer.展开更多
Poly[decaphenylcyclopentasilane] (PDPS)-based photovoltaic cells were fabricated by using mixture solution of PDPS including boron and phosphorous elements. A doping effect of phosphorus and boron into PDPS was invest...Poly[decaphenylcyclopentasilane] (PDPS)-based photovoltaic cells were fabricated by using mixture solution of PDPS including boron and phosphorous elements. A doping effect of phosphorus and boron into PDPS was investigated on the performance of the photovoltaic devices. The solar cell provided short-circuit current density of 0.11 mA/cm2 and open-circuit voltage of 0.81 V under simulated sunlight. Microstructural analysis indicated that PDPS had an amor-phous structure, which would result in the photovoltaic properties.展开更多
Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated ...Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell,with proper optical and electrical arrangements,the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell.In a perovskite/silicon tandem solar cell(PSTSC),a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell.The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power.The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells.Though the theoretical limit of a PSTSC is calculated as~42%,its actual efficiency achieved until now is less than 30%.Therefore,a great scope of research exists in improving the efficiency of PSTSCs.Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs.A tandem device consists of multiple parts,and different configurations can be applied,thus tuning the architecture of the device.Altering various parts may result in significant changes in the efficiency of the device.In this review,competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties.Thus,future directions to improve the efficiency of the device based on architecture design are proposed herein.In particular,the influence of the polarity of PSCs and the surface morphology of silicon solar cells(both front and rear)on determining the properties of the PSTSC are discussed.展开更多
We focused on developing penetration-type semitransparent thin-film solar cells(STSCs) using hydrogenated amorphous Si(a-Si:H) for a building-integrated photovoltaic(BIPV) window system. Instead of conventional p-type...We focused on developing penetration-type semitransparent thin-film solar cells(STSCs) using hydrogenated amorphous Si(a-Si:H) for a building-integrated photovoltaic(BIPV) window system. Instead of conventional p-type a-Si:H, p-type hydrogenated microcrystalline Si oxide(p-μc-SiOx:H) was introduced for a wide-bandgap and conductive window layer. For these purposes, we tuned the CO2/SiH4 flow ratio(R) during p-μc-SiOx:H deposition. The film crystallinity decreased from 50% to 13% as R increased from 0.2 to 1.2. At the optimized R of 0.6, the quantum efficiency was improved under short wavelengths by the suppression of p-type layer parasitic absorption. The series resistance was well controlled to avoid fill factor loss at R = 0.6. Furthermore, we introduced dual buffers comprising p-a-SiOx:H/i-a-Si:H at the p/i interface to alleviate interfacial energy-band mismatch. The a-Si:H STSCs with the suggested window and dual buffers showed improvements in transmittance and efficiency from 22.9% to 29.3% and from 4.62% to 6.41%, respectively, compared to the STSC using a pristine p-a-Si:H window.展开更多
Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the prod...Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide target.Textured surface was obtained in the as-deposited films.The surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration ratio.By varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were obtained.At lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO layers.The overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.展开更多
Hydrogenated microcrystalline silicon (μc-Si:H) intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition (PECVD). The influence of n/i and i/p buffer la...Hydrogenated microcrystalline silicon (μc-Si:H) intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition (PECVD). The influence of n/i and i/p buffer layers on the μc-Si:H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si:H buffer layer at i/p interface. By combining the above methods, the performance of μc-Si:H single-junction and a-Si:H/μc-Si:H tandem solar cells has been significantly improved.展开更多
Hetero-junction solar cells with an mc-Si:H window layer were achieved. The open voltage is increased while short current is decreased with increasing the mc-Si:H layer′s thickness of emitter layer. The highest of Vo...Hetero-junction solar cells with an mc-Si:H window layer were achieved. The open voltage is increased while short current is decreased with increasing the mc-Si:H layer′s thickness of emitter layer. The highest of Voc of 597 mV has obtained. When fixed the thickness of 30 nm, changing the N type from amorphous silicon layer to micro-crystalline layer, the efficiency of the hetero-junction solar cells is increased. Although the hydrogen etching before deposition enables the c-Si substrates to become rough by AFM images, it enhances the formation of epitaxial-like micro-crystalline silicon and better parameters of solar cell can be obtained by implying this process. The best result of efficiency is 13.86% with the Voc of 549.8 mV, Jsc of 32.19 mA·cm-2 and the cell′s area of 1 cm2.展开更多
Using plasma enhanced chemical vapor deposition(PECVD) at 13.56 MHz,a seed layer is fabricated at the initial growth stage of the hydrogenated microcrystalline silicon germanium(μc-Si1-xGex:H) i-layer.The effects o...Using plasma enhanced chemical vapor deposition(PECVD) at 13.56 MHz,a seed layer is fabricated at the initial growth stage of the hydrogenated microcrystalline silicon germanium(μc-Si1-xGex:H) i-layer.The effects of seeding processes on the growth ofμc-Si1-xGex:H i-layers and the performance ofμc-Si1-xGex:H p-i-n single junction solar cells are investigated.By applying this seeding method,theμc-Si1-xGex:H solar cell shows a significant improvement in short circuit current density(Jsc) and fill factor(FF) with an acceptable performance of blue response as aμc-Si:H solar cell even when the Ge content x increases up to 0.3.Finally,an improved efficiency of 7.05%is achieved for theμc-Si0.7Ge0.3:H solar cell.展开更多
Thin film solar cells have been proved the next generation photovoltaic devices due to their low cost,less material consumption and easy mass production.Among them,micro-crystalline Si and Ge based thin film solar cel...Thin film solar cells have been proved the next generation photovoltaic devices due to their low cost,less material consumption and easy mass production.Among them,micro-crystalline Si and Ge based thin film solar cells have advantages of high efficiency and ultrathin absorber layers.Yet individual junction devices are limited in photoelectric conversion efficiency because of the restricted solar spectrum range for its specific absorber.In this work,w e designed a nd simulated a multi-junction solar cell with its four sub-cells selectively absorbing the full solar spectrum including the ultraviolet,green,red as well as near infrared range,respectively.B y tuning the G e content,the record efficiency of 24.80%has been realized with the typical quadruple junction structure of a-Si:H/a-Si0.9Ge0.1:H/μc-Si:H/μc-Si0.5Ge0.5:H.To further reduce the material cost,thickness dependent device performances have been conducted.It can be found that the design of total thickness of 4μm is the optimal device design in balancing the thickness a nd the PCE.While the design of ultrathin quadruple junction device with total thickness of 2μm is the optimized device design regarding cost and long-term stability with a little bit more reduction in PCE.These results indicated that our solar cells combine the advantages of low cost and high stability.Our work may provide a general guidance rule of utilizing the full solar spectrum for developing high efficiency and ultrathin multi-junction solar cells.展开更多
Interdigitated back contact-heterojunction (IBC-HJ) solar cells can have a conversion efficiency of over 25%. However, the front surface passivation and structure have a great influence on the properties of the IBC-...Interdigitated back contact-heterojunction (IBC-HJ) solar cells can have a conversion efficiency of over 25%. However, the front surface passivation and structure have a great influence on the properties of the IBC-HJ solar cell. In this paper, detailed numerical simulations have been performed to investigate the potential of front surface field (FSF) offered by stack of n-type doped and intrinsic amorphous silicon (a-Si) layers on the front surface of IBC-HJ solar cells. Simulations results clearly indicate that the electric field of FSF should be strong enough to repel minority carries and cumulate major carriers near the front surface. However, the overstrong electric field tends to drive electrons into a-Si layer, leading to severe recombination loss. The n-type doped amorphous silicon (n-a-Si) layer has been optimized in terms of doping level and thickness. The optimized intrinsic amorphous silicon (i-a-Si) layer should be as thin as possible with an energy band gap (Es) larger than 1.4 eV. In addition, the simulations concerning interface defects strongly suggest that FSF is essential when the front surface is not passivated perfectly. Without FSF, the IBC-HJ solar cells may become more sensitive to interface defect density.展开更多
基金This work was supported by Zhejiang Energy Group(znkj-2018-118)Key Research and Development Program of Zhejiang Province(2021C01006)+5 种基金Key Project of Zhejiang Province(2021C04009)Science and technology projects in Liaoning Province 2021(2021JH1/10400104)Ningbo“Innovation 2025”Major Project(2020Z098)National Key R&D Program of China(2018YFB1500403)National Natural Science Foundation of China(61974178,61874177,62004199)Youth Innovation Promotion Association(2018333).
文摘In this work,we developed a simple and direct circuit model with a dual two-diode model that can be solved by a SPICE numerical simulation to comprehensively describe the monolithic perovskite/crystalline silicon(PVS/c-Si)tandem solar cells.We are able to reveal the effects of different efficiency-loss mechanisms based on the illuminated current density-voltage(J-V),semi-log dark J-V,and local ideality factor(m-V)curves.The effects of the individual efficiency-loss mechanism on the tandem cell’s efficiency are discussed,including the exp(V/VT)and exp(V/2VT)recombination,the whole cell’s and subcell’s shunts,and the Ohmic-contact or Schottky-contact of the intermediate junction.We can also fit a practical J-V curve and find a specific group of parameters by the trial-and-error method.Although the fitted parameters are not a unique solution,they are valuable clues for identifying the efficiency loss with the aid of the cell’s structure and experimental processes.This method can also serve as an open platform for analyzing other tandem solar cells by substituting the corresponding circuit models.In summary,we developed a simple and effective methodology to diagnose the efficiency-loss source of a monolithic PVS/c-Si tandem cell,which is helpful to researchers who wish to adopt the proper approaches to improve their solar cells.
基金supported by the Hi-Tech Research and Development Program of China (Grant Nos. 2007AA05Z436 and 2009AA050602)the Science and Technology Support Project of Tianjin (Grant No. 08ZCKFGX03500)+2 种基金the National Natural Science Foundation of China (Grant No. 60976051)the International Cooperation Project between China–Greece Government (GrantNo. 2009DFA62580)the Program for New Century Excellent Talents in University of China (NCET-08-0295)
文摘We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.
文摘Solar cells are now widely used as a clean method for electric energy generation. Among various type of solar cells, we compared the ability between amorphous and tandem (amorphous and polycrystalline) silicon solar cells by means of simultaneous running test. This kind of comparison is of importance practically, because the comparison of only inherent characteristics cannot include environmental parameters such as temperature totally. It was concluded that both types of solar cells provided almost the same energy for one year. The amorphous silicon solar cell provided more energy in summer while the tandem solar cell was advantageous in winter. It is due to the fact that the decrease in energy conversion at the higher cell temperature is more noticeable in tandem solar cells.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2009AA05Z422), the National Basic Research Program of China (Grant Nos. 2011CBA00705, 2011CBA00706, and 2011CBA00707), and the Natural Science Foundation of Tianjin (Grant No. 08JCZDJC22200).
文摘This paper identifies the contributions of p-a-SiC:H layers and i-a-Si:H layers to the open circuit voltage of p-i-n type a-Si:H solar cells deposited at a low temperature of 125℃. We find that poor quality p-a-SiC:H films under regular conditions lead to a restriction of open circuit voltage although the band gap of the i-layer varies widely. A significant improvement in open circuit voltage has been obtained by using high quality p-~SiC:H films optimized at the "low-power regime" under low silane flow rates and high hydrogen dilution conditions.
基金Project supported by Hi-Tech Research and Development Program of China (Grant No 2007AA05Z436)Science and Technology Support Project of Tianjin (Grant No 08ZCKFGX03500)+4 种基金National Basic Research Program of China (Grant Nos 2006CB202602 and 2006CB202603)National Natural Science Foundation of China (Grant No 60506003)Starting Project of Nankai University (Grant No J02031)International Cooperation Project Between China-Greece Government (Grant No 2006DFA62390)Program for New Century Excellent Talents in University of China (NCET)
文摘This paper studies boron contamination at the interface between the p and i layers of μc-Si:H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary Ion Mass Spectroscopy. It is found that the mixed-phase μc-Si:H materials with 40% crystalline volume fraction is easy to be affected by the residual boron in the reactor. The experimental results showed that a 500-nm thick μc-Si:H covering layer or a 30-seconds of hydrogen plasma treatment can effectively reduce the boron contamination at the p/i interface. However, from viewpoint of cost reduction, the hydrogen plasma treatment is desirable for solar cell manufacture because the substrate is not moved during the hydrogen plasma treatment.
基金supported by Hi-Tech Research and Development Program of China (Grant Nos.2007AA05Z436 and 2009AA050602)Science and Technology Support Project of Tianjin of China (Grant No.08ZCKFGX03500)+3 种基金National Basic Research Program of China (Grant Nos.2006CB202602 and 2006CB202603)National Natural Science Foundation of China (Grant No.60976051)International Cooperation Project between China-Greece Government (Grant Nos.2006DFA62390 and 2009DFA62580)Program for New Century Excellent Talents in University of China (Grant No.NCET-08-0295)
文摘This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si:H or μc-Si:H covering layer between solar cells. Their effectiveness for the pretreatment is evaluated by means of phosphorus concentration in films, the dark conductivity of p-layer properties and cell performance.
基金supported by the National Basic Research Program of China (Grant Nos 2006CB202602 and 2006CB202603)the Tianjin Assistant Foundation for the National Basic Research Program of China (Grant No 07QTPTJC29500)the Natural Science Foundation of Tianjin (Grant No 07JCYBJC04000)
文摘This paper reports that high-rate-deposition of microcrystalline silicon solar cells was performed by very-highfrequency plasma-enhanced chemical vapor deposition. These solar cells, whose intrinsic μc-Si:H layers were prepared by using a different total gas flow rate (Ftotal), behave much differently in performance, although their intrinsic layers have similar crystalline volume fraction, opto-electronic properties and a deposition rate of - 1.0 nm/s. The influence of Ftotal on the micro-structural properties was analyzed by Raman and Fourier transformed infrared measurements. The results showed that the vertical uniformity and the compact degree of μc-Si:H thin films were improved with increasing Ftotal. The variation of the microstructure was regarded as the main reason for the difference of the J V parameters. Combined with optical emission spectroscopy, we found that the gas temperature plays an important role in determining the microstructure of thin films. With Ftotal of 300 sccm, a conversion efficiency of 8.11% has been obtained for the intrinsic layer deposited at 8.5 A/s (1 A=0.1 nm).
文摘A series of samples deposited by VHF-PECVD at different pressures were studied.The measurement results of photosensitivity (photo conductivity/dark conductivity) and activation energy indicated near the same rule with the change of the pressure.The results measured by Raman scattering spectra,X-ray diffraction and FTIR all proved the evident crystallization of the materials.Treating the p/i interface by hydrogen has a great improving effect on the performance of the microcrystalline silicon (μc-Si) p-i-n solar cells if the treatment time was appropriate.An efficiency of 4.24% for μc-Si p-i-n solar cells deposited by VHF-PECVD was firstly obtained.
文摘In order to improve the efficiency of solar cells based on cubic silicon carbide (3C-SiC), one heterojunction solar cell and two tandem structures were simulated under AM1.5 illumination using SCAPS software. The cells’ performances were studied according to the thickness of the silicon carbide layers. Simulation results allowed to achieve an efficiency of 22.03% with a tandem junction structure using an optimal thickness of 3C-SiC layer.
文摘Poly[decaphenylcyclopentasilane] (PDPS)-based photovoltaic cells were fabricated by using mixture solution of PDPS including boron and phosphorous elements. A doping effect of phosphorus and boron into PDPS was investigated on the performance of the photovoltaic devices. The solar cell provided short-circuit current density of 0.11 mA/cm2 and open-circuit voltage of 0.81 V under simulated sunlight. Microstructural analysis indicated that PDPS had an amor-phous structure, which would result in the photovoltaic properties.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFB1500103)the Joint Funds of the National Natural Science Foundation of China(Grant No.U21A2072)+7 种基金the Natural Science Foundation of Tianjin(Grant No.20JCQNJC02070)China Postdoctoral Science Foundation(Grant No.2020T130317)the Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China(Grant No.B16027)Tianjin Science and Technology Project(Grant No.18ZXJMTG00220)the Key R&D Program of Hebei Province(Grant No.19214301D)the Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central UniversitiesNankai University。
文摘Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell,with proper optical and electrical arrangements,the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell.In a perovskite/silicon tandem solar cell(PSTSC),a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell.The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power.The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells.Though the theoretical limit of a PSTSC is calculated as~42%,its actual efficiency achieved until now is less than 30%.Therefore,a great scope of research exists in improving the efficiency of PSTSCs.Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs.A tandem device consists of multiple parts,and different configurations can be applied,thus tuning the architecture of the device.Altering various parts may result in significant changes in the efficiency of the device.In this review,competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties.Thus,future directions to improve the efficiency of the device based on architecture design are proposed herein.In particular,the influence of the polarity of PSCs and the surface morphology of silicon solar cells(both front and rear)on determining the properties of the PSTSC are discussed.
基金supported by the Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) under grant Nos. 20163010012560 and 20172010104940
文摘We focused on developing penetration-type semitransparent thin-film solar cells(STSCs) using hydrogenated amorphous Si(a-Si:H) for a building-integrated photovoltaic(BIPV) window system. Instead of conventional p-type a-Si:H, p-type hydrogenated microcrystalline Si oxide(p-μc-SiOx:H) was introduced for a wide-bandgap and conductive window layer. For these purposes, we tuned the CO2/SiH4 flow ratio(R) during p-μc-SiOx:H deposition. The film crystallinity decreased from 50% to 13% as R increased from 0.2 to 1.2. At the optimized R of 0.6, the quantum efficiency was improved under short wavelengths by the suppression of p-type layer parasitic absorption. The series resistance was well controlled to avoid fill factor loss at R = 0.6. Furthermore, we introduced dual buffers comprising p-a-SiOx:H/i-a-Si:H at the p/i interface to alleviate interfacial energy-band mismatch. The a-Si:H STSCs with the suggested window and dual buffers showed improvements in transmittance and efficiency from 22.9% to 29.3% and from 4.62% to 6.41%, respectively, compared to the STSC using a pristine p-a-Si:H window.
基金The work has been supported by the Science and Engineering Research Board(SERB),Department of Science and Technology(SR/FTP/PS-175/2012)。
文摘Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide target.Textured surface was obtained in the as-deposited films.The surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration ratio.By varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were obtained.At lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO layers.The overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.
基金supported by the State Key Development Program for Basic Research of China (Nos. 2006CB202602, 2006CB202603)the Tianjin Assistant Foundation for the National Basic Research Program of China (No. 07QTPTJC29500).
文摘Hydrogenated microcrystalline silicon (μc-Si:H) intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition (PECVD). The influence of n/i and i/p buffer layers on the μc-Si:H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si:H buffer layer at i/p interface. By combining the above methods, the performance of μc-Si:H single-junction and a-Si:H/μc-Si:H tandem solar cells has been significantly improved.
基金This project was financially supported by the National Science Foundation of Beijing, China (No.04D063)
文摘Hetero-junction solar cells with an mc-Si:H window layer were achieved. The open voltage is increased while short current is decreased with increasing the mc-Si:H layer′s thickness of emitter layer. The highest of Voc of 597 mV has obtained. When fixed the thickness of 30 nm, changing the N type from amorphous silicon layer to micro-crystalline layer, the efficiency of the hetero-junction solar cells is increased. Although the hydrogen etching before deposition enables the c-Si substrates to become rough by AFM images, it enhances the formation of epitaxial-like micro-crystalline silicon and better parameters of solar cell can be obtained by implying this process. The best result of efficiency is 13.86% with the Voc of 549.8 mV, Jsc of 32.19 mA·cm-2 and the cell′s area of 1 cm2.
基金supportedbytheNationalBasicResearch Program ofChina(Nos.2011CBA00705,2011CBA00706,2011CBA00707)the Natural Science Foundation of Tianjin(No.12JCQNJC01000)the Fundamental Research Funds for the Central Universities
文摘Using plasma enhanced chemical vapor deposition(PECVD) at 13.56 MHz,a seed layer is fabricated at the initial growth stage of the hydrogenated microcrystalline silicon germanium(μc-Si1-xGex:H) i-layer.The effects of seeding processes on the growth ofμc-Si1-xGex:H i-layers and the performance ofμc-Si1-xGex:H p-i-n single junction solar cells are investigated.By applying this seeding method,theμc-Si1-xGex:H solar cell shows a significant improvement in short circuit current density(Jsc) and fill factor(FF) with an acceptable performance of blue response as aμc-Si:H solar cell even when the Ge content x increases up to 0.3.Finally,an improved efficiency of 7.05%is achieved for theμc-Si0.7Ge0.3:H solar cell.
基金the National Natural Science Foundation of China(Grant No.51772049)the Jilin Scientific and Technological Development Program,China(Grant No.20170520159JH)+5 种基金the Thirteenth Five-Year'Scientific and Technological Research Project of the Education Department of Jilin Province,China(Grant No.JJKH20190705IG)the project of Jilin Development and Reform Commission(Grant No.2019C042)The authors also show their gratitude to the National Natural Science Foundation of China(Grant No.51802116)the Natural Science Foundation of Shandong Province(No.ZR2019BE M040)Jinbo Pang acknowledges the National Key Research and Development Program of China(Grant No.2017YFE0102700)from the Ministry of Science and Technology(MOST)of China and the Key Research and Development program of Shandong Province(Major Innovation Project of Science and Technology of Shandong Province)(No.2018YFJH0503)the University of Jinan for the Scientific Research Starting Funds.
文摘Thin film solar cells have been proved the next generation photovoltaic devices due to their low cost,less material consumption and easy mass production.Among them,micro-crystalline Si and Ge based thin film solar cells have advantages of high efficiency and ultrathin absorber layers.Yet individual junction devices are limited in photoelectric conversion efficiency because of the restricted solar spectrum range for its specific absorber.In this work,w e designed a nd simulated a multi-junction solar cell with its four sub-cells selectively absorbing the full solar spectrum including the ultraviolet,green,red as well as near infrared range,respectively.B y tuning the G e content,the record efficiency of 24.80%has been realized with the typical quadruple junction structure of a-Si:H/a-Si0.9Ge0.1:H/μc-Si:H/μc-Si0.5Ge0.5:H.To further reduce the material cost,thickness dependent device performances have been conducted.It can be found that the design of total thickness of 4μm is the optimal device design in balancing the thickness a nd the PCE.While the design of ultrathin quadruple junction device with total thickness of 2μm is the optimized device design regarding cost and long-term stability with a little bit more reduction in PCE.These results indicated that our solar cells combine the advantages of low cost and high stability.Our work may provide a general guidance rule of utilizing the full solar spectrum for developing high efficiency and ultrathin multi-junction solar cells.
基金Acknowledgements This work is supported by the National Natural Science Foundation of China (Grant Nos. 11104319, 11274346, 51202285, 61234005, 51172268 and 51402347), the Solar Energy Action Plan of the Chinese Academy of Sciences (Grant Nos. Y1YT064001, Y1YF034001 and Y2YF014001), and Sci. & Tech. Commission Project of Beijing Municipality (Grant No. Z 151100003515003).
文摘Interdigitated back contact-heterojunction (IBC-HJ) solar cells can have a conversion efficiency of over 25%. However, the front surface passivation and structure have a great influence on the properties of the IBC-HJ solar cell. In this paper, detailed numerical simulations have been performed to investigate the potential of front surface field (FSF) offered by stack of n-type doped and intrinsic amorphous silicon (a-Si) layers on the front surface of IBC-HJ solar cells. Simulations results clearly indicate that the electric field of FSF should be strong enough to repel minority carries and cumulate major carriers near the front surface. However, the overstrong electric field tends to drive electrons into a-Si layer, leading to severe recombination loss. The n-type doped amorphous silicon (n-a-Si) layer has been optimized in terms of doping level and thickness. The optimized intrinsic amorphous silicon (i-a-Si) layer should be as thin as possible with an energy band gap (Es) larger than 1.4 eV. In addition, the simulations concerning interface defects strongly suggest that FSF is essential when the front surface is not passivated perfectly. Without FSF, the IBC-HJ solar cells may become more sensitive to interface defect density.