Effect of an Adsorbent on Recombination and Band-Edge Movement in Dye-Sensitized TiO2Solar Cells:  Evidence for Surface Passivation

Highly luminescent silver indium sulfide (AgInS2) nanoparticles were synthesized by dropwise injection of a sulfur precursor solution into a cationic metal precursor solution. The two-step reaction including the formation of silver sulfide (Ag2S) nanoparticles as an intermediate and their conversion to AgInS2 nanoparticles, occurred during the dropwise injection. The crystal structure of the AgInS2 nanoparticles differed according to the temperature of the metal precursor solution. Specifically, the tetragonal crystal phase was obtained at 140 °C, and the orthorhombic crystal phase was obtained at 180 °C. Furthermore, when the AgInS2 nanoparticles were coated with a gallium sulfide (GaSx) shell, the nanoparticles with both crystal phases emitted a spectrally narrow luminescence, which originated from the band-edge transition of AgInS2. Tetragonal AgInS2 exhibited narrower band-edge emission (full width at half maximum, FWHM = 32.2 nm) and higher photoluminescence (PL) quantum yield (QY) (49.2%) than those of the orthorhombic AgInS2 nanoparticles (FWHM = 37.8 nm, QY = 33.3%). Additional surface passivation by alkylphosphine resulted in higher PL QY (72.3%) with a narrow spectral shape.

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Influence of 4-tert-butylpyridine/guanidinium thiocyanate co-additives on band edge shift and recombination of dye-sensitized solar cells: experimental and theoretical aspects

Electrochimica Acta ◽

10.1016/j.electacta.2015.10.103 ◽

2015 ◽

Vol 185 ◽

pp. 69-75 ◽

Cited By ~ 12

Author(s):

Yuqiao Wang ◽

Jing Lu ◽

Jie Yin ◽

Gang Lü ◽

Yingmin Cui ◽

...

Keyword(s):

Solar Cells ◽

Dye Sensitized Solar Cells ◽

Band Edge ◽

Dye Sensitized ◽

Guanidinium Thiocyanate ◽

Sensitized Solar Cells

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Luminescence in Si/Strained Si1−xGex Heterostructures

MRS Proceedings ◽

10.1557/proc-379-387 ◽

1995 ◽

Vol 379 ◽

Author(s):

J.C. Sturm ◽

A. St. Amour ◽

Y. Lacroix ◽

M.L.W. Thewalt

Keyword(s):

Temperature Dependence ◽

Room Temperature ◽

Surface Passivation ◽

Band Edge ◽

Strained Si ◽

Edge Luminescence ◽

Recent Developments ◽

High Pump ◽

Band Edge Luminescence ◽

First Time

ABSTRACTThis paper quickly reviews the structure of band-edge luminescence in Si/strained Si1−xGex heterostructures, and then focusses on two recent developments -- the origin of “deep” sub-bandgap luminescence which is sometimes observed in structures grown by Molecular Beam Epitaxy (MBE) and the understanding of the temperature dependence of the band-edge luminescence (up to room temperature). Strong evidence will be presented that the origin of the deep luminescence is radiation damage, and that generated defects are segregated or trapped in the SilxGex layers. The modelling of the temperature dependence by twocarrier numerical simulation is presented for the first time. The work and experimental data show convincingly that the strength of the luminescence at high temperature is controlled by recombination at the top silicon surface, which in turn can be controlled by surface passivation. At high pump powers and low temperatures, Auger recombination reduces the lifetime in the Si1−xGex layers, and leads to a luminescence vs. temperature which is flat up to 250 K and which is reduced only by a factor of three at room temperature.

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