The Mechanism for Defect Generation Studied by Photodegradation of A-Si:H Solar Cells Under Electrical Bias

ABSTRACTThe light induced degradation of a-Si:H p-i-n solar cells under electrical bias has been systematically studied. By comparing the results with the light intensity dependence of cell degradation under open circuit condition, we show that the only recombination mechanism, which can be consistent with the experimental data in both cases, is based on the bimolecular recombination between a free hole and a trapped electron at the “weak” bond site. Other possibilities for defect creation are also pointed out.

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Effect of non-ohmic contacts on the light-intensity dependence of the open-circuit voltage in organic solar cells

Applied Physics Letters ◽

10.1063/1.4960151 ◽

2016 ◽

Vol 109 (5) ◽

pp. 053302 ◽

Cited By ~ 20

Author(s):

S. Solak ◽

P. W. M. Blom ◽

G. A. H. Wetzelaer

Keyword(s):

Solar Cells ◽

Light Intensity ◽

Organic Solar Cells ◽

Ohmic Contacts ◽

Open Circuit Voltage ◽

Open Circuit ◽

Intensity Dependence

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Light Intensity-dependent Variation in Defect Contributions to Charge Transport and Recombination in a Planar MAPbI3 Perovskite Solar Cell

Scientific Reports ◽

10.1038/s41598-019-56338-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Shinyoung Ryu ◽

Duc Cuong Nguyen ◽

Na Young Ha ◽

Hui Joon Park ◽

Y. H. Ahn ◽

...

Keyword(s):

Solar Cell ◽

Ideality Factor ◽

Internal Quantum Efficiency ◽

Intensity Variation ◽

Charge Trapping ◽

Equation Model ◽

Open Circuit ◽

Equivalent Circuit Analysis ◽

Intensity Dependence ◽

Bimolecular Recombination

AbstractWe investigated operation of a planar MAPbI3 solar cell with respect to intensity variation ranging from 0.01 to 1 sun. Measured J-V curves consisted of space-charge-limited currents (SCLC) in a drift-dominant range and diode-like currents in a diffusion-dominant range. The variation of power-law exponent of SCLC showed that charge trapping by defects diminished as intensity increased, and that drift currents became eventually almost ohmic. Diode-like currents were analysed using a modified Shockley-equation model, the validity of which was confirmed by comparing measured and estimated open-circuit voltages. Intensity dependence of ideality factor led us to the conclusion that there were two other types of defects that contributed mostly as recombination centers. At low intensities, monomolecular recombination occurred due to one of these defects in addition to bimolecular recombination to result in the ideality factor of ~1.7. However, at high intensities, another type of defect not only took over monomolecular recombination, but also dominated bimolecular recombination to result in the ideality factor of ~2.0. These ideality-factor values were consistent with those representing the intensity dependence of loss-current ratio estimated by using a constant internal-quantum-efficiency approximation. The presence of multiple types of defects was corroborated by findings from equivalent-circuit analysis of impedance spectra.

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