Solution-processed TiO2 as a hole blocking layer in PEDOT:PSS/n-Si heterojunction solar cells

The junction properties at the solution-processed titanium dioxide (TiO2)/n-type crystalline Si(n-Si) interface were studied for poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/n-Si heterojunction solar cells by the steady-state photovoltaic performance and transient reverse recovery characterizations. The power conversion efficiency could be increased from 11.23% to 13.08% by adjusting the layer thickness of TiO2 together with increasing open-circuit voltage and suppressed dark saturation current density. These findings originate from the enhancement of the carrier collection efficiency at the n-Si/cathode interface. The transient reverse recovery characterization revealed that the surface recombination velocity S was ∼375 cm/s for double TiO2 interlayer of ∼2 nm thickness. This value was almost the same as that determined by microwave photoconductance decay measurement. These findings suggest that solution-processed TiO2 has potential as a hole blocking layer for the crystalline Si photovoltaics.

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Resistive Losses at c-Si/a-Si:H/ZnO Contacts for Heterojunction Solar Cells

MRS Proceedings ◽

10.1557/proc-0989-a18-04 ◽

2007 ◽

Vol 989 ◽

Author(s):

Florian Einsele ◽

Phillip Johannes Rostan ◽

Uwe Rau

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Fill Factor ◽

High Efficiency ◽

Surface Recombination ◽

Open Circuit ◽

Surface Recombination Velocity ◽

High Hydrogen ◽

Solar Cell Performance ◽

Heterojunction Solar Cells

AbstractWe study resistive losses at (p)c-Si/(p)Si:H/(n)ZnO heterojunction back contacts for high efficiency silicon solar cells. We find that a low tunnelling resistance for the (p)a-Si:H/(n)ZnO part of the junction requires deposition of Si:H with a high hydrogen dilution RH > 40 resulting in a highly doped μc-Si:H layer. Such a μc-Si:H layer if deposited directly on a Si wafer yields a surface recombination velocity of S  180 cm/s. Using the same layer as part of a (p)c-Si/(p)Si:H/(n)ZnO back contact in a solar cell results in an open circuit voltage Voc = 640 mV and a fill factor FF = 80 %. Insertion of an (i)a-Si-layer between the μc-Si:H and the wafer leads to a further decrease of S and, for the solar cells to an increase of VOC. However, if the thickness of this intrinsic layer exceeds a threshold of 3 nm, resistive losses lead to a degradation of the fill factor of the solar cells. These resistive losses result from a valence band offset δEV between a-Si:H and c-Si of about 600 meV. The fill factor losses overcompensate the VOC gain such that there is no benefit of the (i)a-Si:H interlayer for the overall solar cell performance when using an (i)a-Si:H/(p)uc-Si:H double layer.

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Numerical Simulation Analysis of Ag Crystallite Effects on Interface of Front Metal and Silicon in the PERC Solar Cell

Energies ◽

10.3390/en14030592 ◽

2021 ◽

Vol 14 (3) ◽

pp. 592

Author(s):

Myeong Sang Jeong ◽

Yonghwan Lee ◽

Ka-Hyun Kim ◽

Sungjin Choi ◽

Min Gu Kang ◽

...

Keyword(s):

Solar Cells ◽

Solar Cell ◽

High Efficiency ◽

Open Circuit Voltage ◽

Surface Recombination ◽

Open Circuit ◽

Surface Recombination Velocity ◽

Metal Interface ◽

Ag Crystallites ◽

Recombination Velocity

In the fabrication of crystalline silicon solar cells, the contact properties between the front metal electrode and silicon are one of the most important parameters for achieving high-efficiency, as it is an integral element in the formation of solar cell electrodes. This entails an increase in the surface recombination velocity and a drop in the open-circuit voltage of the solar cell; hence, controlling the recombination velocity at the metal-silicon interface becomes a critical factor in the process. In this study, the distribution of Ag crystallites formed on the silicon-metal interface, the surface recombination velocity in the silicon-metal interface and the resulting changes in the performance of the Passivated Emitter and Rear Contact (PERC) solar cells were analyzed by controlling the firing temperature. The Ag crystallite distribution gradually increased corresponding to a firing temperature increase from 850 ∘C to 950 ∘C. The surface recombination velocity at the silicon-metal interface increased from 353 to 599 cm/s and the open-circuit voltage of the PERC solar cell decreased from 659.7 to 647 mV. Technology Computer-Aided Design (TCAD) simulation was used for detailed analysis on the effect of the surface recombination velocity at the silicon-metal interface on the PERC solar cell performance. Simulations showed that the increase in the distribution of Ag crystallites and surface recombination velocity at the silicon-metal interface played an important role in the decrease of open-circuit voltage of the PERC solar cell at temperatures of 850–900 ∘C, whereas the damage caused by the emitter over fire was determined as the main cause of the voltage drop at 950 ∘C. These results are expected to serve as a steppingstone for further research on improvement in the silicon-metal interface properties of silicon-based solar cells and investigation on high-efficiency solar cells.

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Numerical Simulation of Single Junction InGaN Solar Cell by SCAPS

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.821.407 ◽

2019 ◽

Vol 821 ◽

pp. 407-413 ◽

Cited By ~ 2

Author(s):

Mohamed Orabi Moustafa ◽

Tariq Alzoubi

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Collection Efficiency ◽

Short Circuit ◽

Photovoltaic Performance ◽

Surface Recombination ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Bandgap Energy ◽

Single Junction

The performance of the InGaN single-junction thin film solar cells has been analyzed numerically employing the Solar Cell Capacitance Simulator (SCAPS-1D). The electrical properties and the photovoltaic performance of the InGaN solar cells were studied by changing the doping concentrations and the bandgap energy along with each layer, i.e. n-and p-InGaN layers. The results reveal an optimum efficiency of the InGaN solar cell of ~ 15.32 % at a band gap value of 1.32 eV. It has been observed that lowering the doping concentration NA leads to an improvement of the short circuit current density (Jsc) (34 mA/cm2 at NA of 1016 cm−3). This might be attributed to the increase of the carrier mobility and hence an enhancement in the minority carrier diffusion length leading to a better collection efficiency. Additionally, the results show that increasing the front layer thickness of the InGaN leads to an increase in the Jsc and to the conversion efficiency (η). This has been referred to the increase in the photogenerated current, as well as to the less surface recombination rate.

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The Effect of Al-BSF on Seff and Rb in Industrialized Mono-Silicon Solar Cells

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.472-475.1846 ◽

2012 ◽

Vol 472-475 ◽

pp. 1846-1850

Author(s):

Shan Shan Dai ◽

Gao Jie Zhang ◽

Xiang Dong Luo ◽

Jing Xiao Wang ◽

Wen Jun Chen ◽

...

Keyword(s):

Solar Cells ◽

Spectral Response ◽

Short Circuit ◽

Rear Surface ◽

Surface Recombination ◽

Short Circuit Current ◽

Open Circuit ◽

Surface Recombination Velocity ◽

Silicon Solar Cells ◽

Back Surface

In this work, the effect of aluminum back surface field formed by screen printed various amount of Al paste on the effective rear surface recombination velocity (Seff) and the internal rear reflectance coeffeicient (Rb) of commercial mono-silicon solar cells was investigated. We demonstrated the effect of Seffand Rbon the performance of Al-BSF solar cells by simulating them with PC1D. The simulated results showed that the lower Seffcould get higher open circuit voltage (Voc), at the same time, the larger Rbcould get higher short-circuit current (Isc). Experimentally, we investigated the Seffand Rbthrough depositing Al paste with various amount (3.7, 5, 6, and 8 mg/cm2) for fabricating Al-BSF mono-silicon solar cells. Four group cells were characterized by light I-V, spectral response, hemispherical reflectance and scanning electron microscope (SEM) measurements. It was found that, a minimum Seffof 350 cm/s was gotten from the cells with Al paste of 8 mg/cm2, which was extracted by matching quantum efficiency (QE) from 800 nm to 1200 nm with PC1D, and a maximum Rbof 53.5% was obtained from Al paste of 5 mg/cm2by calculating at 1105 nm with PC1D. When the amount of Al paste was higher than 5mg/cm2, there were less Seffand lower Rb. On the other hand, when Al amount was 3.7mg/cm2, it was too little to form a closed BSF. Based on the SEM graphs and simulations with PC1D, a simple explaination was proposed for the experimental results.

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Highly efficient hybrid thin-film solar cells using a solution-processed hole-blocking layer

Physical Chemistry Chemical Physics ◽

10.1039/c2cp44468b ◽

2013 ◽

Vol 15 (6) ◽

pp. 1788-1792 ◽

Cited By ~ 9

Author(s):

Ji Hoon Seo ◽

Dong-Ho Kim ◽

Se-Hun Kwon ◽

Yun Chang Park ◽

Hyung Hwan Jung ◽

...

Keyword(s):

Thin Film ◽

Solar Cells ◽

Thin Film Solar Cells ◽

Blocking Layer ◽

Solution Processed ◽

Hybrid Thin Film ◽

Highly Efficient ◽

Hole Blocking Layer

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High open-circuit voltage small-molecule p-DTS(FBTTh2)2:ICBA bulk heterojunction solar cells – morphology, excited-state dynamics, and photovoltaic performance

Journal of Materials Chemistry A ◽

10.1039/c4ta06256f ◽

2015 ◽

Vol 3 (4) ◽

pp. 1530-1539 ◽

Cited By ~ 31

Author(s):

Aung Ko Ko Kyaw ◽

Dominik Gehrig ◽

Jie Zhang ◽

Ye Huang ◽

Guillermo C. Bazan ◽

...

Keyword(s):

Solar Cells ◽

Excited State ◽

Solar Cell ◽

Small Molecule ◽

Open Circuit Voltage ◽

Bulk Heterojunction ◽

Photovoltaic Performance ◽

Open Circuit ◽

Heterojunction Solar Cells ◽

Bulk Heterojunction Solar Cell

A high VOC of 1V is achieved in the bulk heterojunction solar cell using the solution-processed small molecule donor p-DTS(FBTTh2)2 and indene-C60 bis-adduct acceptor.

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