The effect of rear surface passivation layer thickness on high efficiency solar cells with planar and scattering metal reflectors

2012 ◽  
Author(s):  
Yang Yang ◽  
Hamid Mehrvarz ◽  
Supriya Pillai ◽  
Martin Green ◽  
Henner Kampwerth ◽  
...  
Keyword(s):  
Solar Cells ◽  
Layer Thickness ◽  
High Efficiency ◽  
Surface Passivation ◽  
Rear Surface ◽  
Passivation Layer ◽  
High Efficiency Solar Cells

scholarly journals Design of Grating Al2O3 Passivation Structure Optimized for High-Efficiency Cu(In,Ga)Se2 Solar Cells

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4849
Author(s):  
Chan Hyeon Park ◽  
Jun Yong Kim ◽  
Shi-Joon Sung ◽  
Dae-Hwan Kim ◽  
Yun Seon Do
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Surface Passivation ◽  
Rear Surface ◽  
Maximum Efficiency ◽  
Structural Factors ◽  
Carrier Recombination ◽  
Cigs Solar Cells ◽  
Effective Carrier ◽  
Opening Width

In this paper, we propose an optimized structure of thin Cu(In,Ga)Se2 (CIGS) solar cells with a grating aluminum oxide (Al2O3) passivation layer (GAPL) providing nano-sized contact openings in order to improve power conversion efficiency using optoelectrical simulations. Al2O3 is used as a rear surface passivation material to reduce carrier recombination and improve reflectivity at a rear surface for high efficiency in thin CIGS solar cells. To realize high efficiency for thin CIGS solar cells, the optimized structure was designed by manipulating two structural factors: the contact opening width (COW) and the pitch of the GAPL. Compared with an unpassivated thin CIGS solar cell, the efficiency was improved up to 20.38% when the pitch of the GAPL was 7.5–12.5 μm. Furthermore, the efficiency was improved as the COW of the GAPL was decreased. The maximum efficiency value occurred when the COW was 100 nm because of the effective carrier recombination inhibition and high reflectivity of the Al2O3 insulator passivation with local contacts. These results indicate that the designed structure has optimized structural points for high-efficiency thin CIGS solar cells. Therefore, the photovoltaic (PV) generator and sensor designers can achieve the higher performance of photosensitive thin CIGS solar cells by considering these results.

Advanced Passivation Technology and Loss Factor Minimization for High Efficiency Solar Cells

2015 ◽  
Vol 15 (10) ◽  
pp. 7699-7705 ◽  
Author(s):  
Cheolmin Park ◽  
Nagarajan Balaji ◽  
Sungwook Jung ◽  
Jaewoo Choi ◽  
Minkyu Ju ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Refractive Index ◽  
Solar Cells ◽  
High Efficiency ◽  
Surface Passivation ◽  
Surface Recombination ◽  
Optimization Techniques ◽  
Crystal Defects ◽  
Passivation Layer ◽  
Surface Recombination Velocity

High-efficiency Si solar cells have attracted great attention from researchers, scientists, photovoltaic (PV) industry engineers for the past few decades. With thin wafers, surface passivation becomes necessary to increase the solar cells efficiency by overcoming several induced effects due to associated crystal defects and impurities of c-Si. This paper discusses suitable passivation schemes and optimization techniques to achieve high efficiency at low cost. SiNx film was optimized with higher transmittance and reduced recombination for using as an effective antireflection and passivation layer to attain higher solar cell efficiencies. The higher band gap increased the transmittance with reduced defect states that persisted at 1.68 and 1.80 eV in SiNx films. The thermal stability of SiN (Si-rich)/SiN (N-rich) stacks was also studied. Si-rich SiN with a refractive index of 2.7 was used as a passivation layer and N-rich SiN with a refractive index of 2.1 was used for thermal stability. An implied VOC of 720 mV with a stable lifetime of 1.5 ms was obtained for the stack layer after firing. Si–N and Si–H bonding concentration was analyzed by FTIR for the correlation of thermally stable passivation mechanism. The passivation property of spin coated Al2O3 films was also investigated. An effective surface recombination velocity of 55 cm/s with a high density of negative fixed charges (Qf) on the order of 9×1011 cm−2 was detected in Al2O3 films.

scholarly journals Dielectric-Based Rear Surface Passivation Approaches for Cu(In,Ga)Se2 Solar Cells—A Review

2019 ◽  
Vol 9 (4) ◽  
pp. 677 ◽  
Author(s):  
Gizem Birant ◽  
Jessica de Wild ◽  
Marc Meuris ◽  
Jef Poortmans ◽  
Bart Vermang
Keyword(s):  
Solar Cells ◽  
Surface Passivation ◽  
Short Circuit ◽  
Rear Surface ◽  
Short Circuit Current ◽  
Dielectric Materials ◽  
Open Circuit ◽  
Absorber Layer ◽  
Passivation Layer ◽  
Solar Simulator

This review summarizes all studies which used dielectric-based materials as a passivation layer at the rear surface of copper indium gallium (di)selenide, Cu(In,Ga)Se2, (CIGS)-based thin film solar cells, up to 2019. The results regarding the kind of dielectric materials, the deposition techniques, contacting approaches, the existence of additional treatments, and current–voltage characteristics (J–V) of passivated devices are emphasized by a detailed table. The techniques used to implement the passivation layer, the contacting approach for the realization of the current flow between rear contact and absorber layer, additional light management techniques if applicable, the solar simulator results, and further characterization techniques, i.e., external quantum efficiency (EQE) and photoluminescence (PL), are shared and discussed. Three graphs show the difference between the reference and passivated devices in terms of open-circuit voltage (Voc), short-circuit current (Jsc), and efficiency (η), with respect to the thicknesses of the absorber layer. The effects of the passivation layer at the rear surface are discussed based on these three graphs. Furthermore, an additional section is dedicated to the theoretical aspects of the passivation mechanism.

scholarly journals Simulated Study and Surface Passivation of Lithium Fluoride-Based Electron Contact for High-Efficiency Silicon Heterojunction Solar Cells

2021 ◽  
Author(s):  
Muhammad Quddammah Khokhar ◽  
Shahzad Qamar Hussain ◽  
Sanchari Chowdhury ◽  
Muhammad Aleem Zahid ◽  
Pham Duy Phong ◽  
...  
Keyword(s):  
Solar Cells ◽  
Lithium Fluoride ◽  
High Efficiency ◽  
Surface Passivation ◽  
Minority Carrier Lifetime ◽  
Open Circuit ◽  
Passivation Layer ◽  
Heterojunction Solar Cells ◽  
Electron Extraction ◽  
Silicon Heterojunction Solar Cells

Abstract Numerical simulation and experimental techniques were used to investigate lithium fluoride (LiFx) films as an electron extraction layer for the application of silicon heterojunction (SHJ) solar cells, with a focus on the paths toward excellent surface passivation and superior efficiency. The presence of a 7 nm thick hydrogenated intrinsic amorphous silicon (a-Si:H(i)) passivation layer along with thermally evaporated 4 nm thick LiFx resulted in outstanding passivation properties and suppresses the recombination of carriers. As a result, minority carrier lifetime (τeff) as well as implied open-circuit voltage (iVoc) reached up 933 μs and iVoc of 734 mV, accordingly at 120°C annealing temperature. A detailed simulated study was performed for the complete LiFx based SHJ solar cells to achieve superior efficiency. Optimized performance of SHJ solar cells using a LiFx layer thickness of 4 nm with energy bandgap (Eg) of 10.9 eV and the work function of 3.9 eV was shown as: Voc=745.7 mV, Jsc=38.21 mA/cm2, FF=82.17%, and =23.41%. Generally, our work offers an improved understanding of the passivation layer, electron extraction layer, and their combined effects on SHJ solar cells via simulation.

Rear surface passivation of high‐efficiency silicon solar cells by a floating junction

1996 ◽  
Vol 80 (6) ◽  
pp. 3574-3586 ◽  
Author(s):  
Pietro P. Altermatt ◽  
Gernot Heiser ◽  
Ximing Dai ◽  
Jörn Jürgens ◽  
Armin G. Aberle ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Surface Passivation ◽  
Rear Surface ◽  
Silicon Solar Cells

scholarly journals Rear surface passivation of ultra-thin CIGS solar cells using atomic layer deposited HfOx

2020 ◽  
Vol 11 ◽  
pp. 10
Author(s):  
Gizem Birant ◽  
Jorge Mafalda ◽  
Romain Scaffidi ◽  
Jessica de Wild ◽  
Dilara Gokcen Buldu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Surface Passivation ◽  
Rear Surface ◽  
Point Contact ◽  
Layer Growth ◽  
Absorber Layer ◽  
Passivation Layer ◽  
Mis Structure ◽  
Cell Parameters ◽  
Cigs Solar Cells

In this work, hafnium oxide layer is investigated as rear surface passivation layer for ultra-thin (550 nm) CIGS solar cells. Point contact openings in the passivation layer are realized by spin-coating potassium fluoride prior to absorber layer growth. Contacts are formed during absorber layer growth and visualized with scanning electron microscopy (SEM). To assess the passivating qualities, HfOx was applied in a metal-insulator-semiconductor (MIS) structure, and it demonstrates a low interface trap density in combination with a negative density of charges. Since we used ultra-thin devices that are ideal to probe improvements at the rear, solar cell results indicated improvements in all cell parameters by the addition of 2 nm thick HfOx passivation layer with contact openings.

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