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    WO3:AgInS2 quantum dot electron transport layers in enhanced perovskite solar cells
    (2023-04-14)
    Seriwattanachai, Chaowaphat
    ;
    Kaewprajak, Anusit
    ;
    Sukgorn, Nuttaya
    ;
    Kumnorkaew, Pisist
    ;
    Nukeaw, Jiti
    The development of the electron transport layers (ETL) was crucially important for the improvement of charge extraction and transportation in perovskite solar cells (PSCs). Here, dual electron transport layers of TiO<inf>2</inf> and WO<inf>3</inf> mixed with different sizes of AgInS<inf>2</inf> quantum dots (TiO<inf>2</inf>/WO<inf>3</inf>:AgInS<inf>2</inf> QDs) were fabricated for planar perovskite solar cells. The peak intensity of the photoluminescence (PL) of the synthesized AgInS<inf>2</inf> QDs were redshifted from 554 to 655 nm with an increased radius of AgInS<inf>2</inf> QDs from 3.82 ± 0.52 to 7.78 ± 1.37 nm. The PL intensity of the perovskite film on TiO<inf>2</inf>/WO<inf>3</inf>:AgInS<inf>2</inf> QDs was quenched by the addition of AgInS<inf>2</inf> QDs. The improved device stability was probably caused by the WO<inf>3</inf>:AgInS<inf>2</inf> QDs layer protecting the interface of perovskite layers from direct contact with TiO<inf>2</inf> to prevent UV decomposing. Therefore, the TiO<inf>2</inf>/WO<inf>3</inf>:AgInS<inf>2</inf> QDs as electron transport layers promoted the perovskite solar cell performance and enhanced the long-term stability. Graphical abstract: [Figure not available: see fulltext.].
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    The current state of the art in internal additive materials and quantum dots for improving efficiency and stability against humidity in perovskite solar cells
    (2022-12-01)
    Sanglee, Kanyanee
    ;
    Nukunudompanich, Methawee
    ;
    Part, Florian
    ;
    Zafiu, Christian
    ;
    Bello, Gianluca
    The remarkable optoelectronic capabilities of perovskite structures enable the achievement of astonishingly high-power conversion efficiencies on the laboratory scale. However, a critical bottleneck of perovskite solar cells is their sensitivity to the surrounding humid environment affecting drastically their long-term stability. Internal additive materials together with surface passivation, polymer-mixed perovskite, and quantum dots, have been investigated as possible strategies to enhance device stability even in unfavorable conditions. Quantum dots (QDs) in perovskite solar cells enable power conversion efficiencies to approach 20%, making such solar cells competitive to silicon-based ones. This mini-review summarized the role of such QDs in the perovskite layer, hole-transporting layer (HTL), and electron-transporting layer (ETL), demonstrating the continuous improvement of device efficiencies.
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    Retraction:All-optical switches based-on GaAs/AlAs quantum dots vertical cavities
    (2012-01-01)
    Teeka, C.
    ;
    Jomtarak, R.
    ;
    P. Yupapin, P.
    In this paper, we present an all-optical switch based on self-assembled GaAs/AlAs quantum dots (QDs) within a vertical cavity. Two essential aspects of this novel device have been investigated, which includes the QD/cavity nonlinearity with appropriately designed mirrors and the intersubband carrier dynamics inside QDs. Verticalreflection- type switches have been investigated with an asymmetric cavity that consists of 12 periods of GaAs/Al0.8Ga0.2As for the front mirror and 25 periods for the back mirror. The thicknesses of the GaAs and AlGaAs layers are chosen to be 89 and 102 nm, respectively. To give a dot-in-a-well (DWELL) structure, 65nm dimension of Si was deposited within an 20nm AlAs QW. All-optical switching via the QD excited states has been achieved with a time constant down to 750 fs, wavelength tunability over 29.5 nm. These results demonstrate that QDs within a vertical cavity have great advantages to realize low-power consumption polarization-insensitive micrometer-sized switching devices for the future optical communication and signal processing systems. © 2010 Published by Elsevier Ltd.