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Cesium Moderation and Structural Transformation on α-CsPbI2Br Perovskite Durability via Cation Retarding Migration: A Combined Simulation and Experimental Study
(2025-03-01)
Henjongchom, Nakorn
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Ruengsrisang, Waranchit
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Soe, Kay Thi
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Kayunkid, Navaphun
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Thongprong, Non
Preliminary density functional theory studies suggest that cesium-ion (Cs<sup>+</sup>) migration possesses a low energy barrier at defective surfaces, which potentially induces lattice distortion of α-CsPbI<inf>2</inf>Br perovskites. Herein, we introduced surface design via mixed-cation and mixed-halide methods to enhance the durability and functionality of all-inorganic CsPbI<inf>2</inf>Br solar cells. The adsorption and adhesion energies indicate that formamidinium bromide (FABr) passivation creates a nonbonding surface with resistance to water molecules and induces lattice reconstruction at the surface into a cubic-like structure. Experimental validation in solar cell applications reveals that nonencapsulated formamidinium bromide − based devices can retain 84 % of the initial efficiency (13.29 %) after 336 h of use with 40 %–43 % of relative humidity, outperforming the reference cell that retained 20 % of the original efficiency (10.31 %) after 144 h. This findings highlight the dual role of FABr passivation in stabilizing the surface and reorganizing the lattice structure, contributing to significantly enhanced durability and performance CsPbI<inf>2</inf>Br solar cells.
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Effective performance for undoped and boron-doped double-layered nanoparticles-copper telluride and manganese telluride on tungsten oxide photoelectrodes for solar cell devices
(2016-11-01)
Srathongluan, Pornpimol
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Choopun, Supab
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Tubtimtae, Auttasit
This work demonstrates the synthesis of a novel double-layered Cu<inf>2−x</inf>Te/MnTe structure on a WO<inf>3</inf> photoelectrode as a solar absorber for photovoltaic devices. Each material absorber is synthesized using a successive ionic layer adsorption and reaction (SILAR) method. The synthesized individual particle sizes are Cu<inf>2−x</inf>Te(17) ∼5–10 nm and MnTe(3) ∼2 nm, whereas, the aggregated particle sizes of undoped and boron-doped Cu<inf>2−x</inf>Te(17)/MnTe(11) are ∼50 and 150 nm, respectively. The larger size after doping is due to the interconnecting of nanoparticles as a network-like structure. A new alignment of the energy band is constructed after boron/MnTe(11) is coated on boron/Cu<inf>2−x</inf>Te nanoparticles (NPs), leading to a narrower E<inf>g</inf> equal to 0.58 eV. Then, the valence band maximum (VBM) and conduction band minimum (CBM) with a trap state are also up-shifted to near the CBM of WO<inf>3</inf>, leading to the shift of a Fermi level for ease of electron injection. The best efficiency of 1.41% was yielded for the WO<inf>3</inf>/boron-doped [Cu<inf>2−x</inf>Te(17)/MnTe(11)] structure with a photocurrent density (J<inf>sc</inf>) = 16.43 mA/cm<sup>2</sup>, an open-circuit voltage (V<inf>oc</inf>) = 0.305 V and a fill factor (FF) = 28.1%. This work demonstrates the feasibility of this double-layered structure with doping material as a solar absorber material.
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Photostability testing for coumarin-153 doped ZnO thin films prepared with spin-coating technique
(2016-01-01)
Brankov, Marijana
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Locharoenrat, Kitsakorn
The main aim behind the present study is solar cells of increased efficiency and low cost per unit of power generation, specifically dye-sensitized cells. Their first component is semiconducting ZnO commonly used to build photovoltaics, which absorbs sunlight in the ultraviolet region. The second component, the dye coumarin-153 that absorbs in a lower-energy spectral region, enhances the light harvesting. We study the optical absorbance and fluorescence for the combination of coumarin-153 with ZnO nanoparticles, which are prepared in sol-gel films formed using a simple spin-coating technique for creating a stable photovoltaic.
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Design of a dual-input buck-boost converter for mobile back-lighting applications
(2012-04-01)
Eguchi, Kei
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Pongswatd, Sawai
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Julsereewong, Amphawan
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Oota, Ichirou
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Terada, Shinya
For mobile back-lighting applications, a dual-input white LED (WLED) driver using a bi-direction buck-boost converter is proposed in this paper. The proposed driver has two input terminals: battery input V <inf>in1</inf> and solar-cell input V <inf>in2</inf>. Unlike conventional drivers using boost converters, step-up SC DC-DC converters, and so on, the proposed converter drives the anode and the cathode of LEDs by using the solar-cell's voltage and the negative stepped-down voltage, respectively. Furthermore, by converting solar energy, the proposed driver can charge a rechargeable battery when the LED backlight is standby mode. Therefore, the proposed driver can achieve long battery lifetime. The validity of the proposed driver is confirmed by SPICE simulations and experiments. SPICE simulations show that the proposed driver can offer the sufficient voltage to drive LEDs by using solar energy and battery energy in spite of the variation in V <inf>in2</inf>. Furthermore, by employing a bi-direction buck-boost converter, the proposed driver provides us to realize long battery lifetime, because the battery charge process was confirmed by experiments. © 2012 ICIC International.
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A switched-capacitor-based serial DC-DC converter using clean energy power supplies
(2011-06-01)
Eguchi, Kei
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Pongswatd, Sawai
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Tirasesth, Kitti
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Sasaki, Hirofumi
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Oota, Ichirou
Aimed at mobile back-lighting applications, a switched-capacitor-based serial DC-DC converter is proposed in this paper. By using battery energy and solar energy, the proposed converter generates the stepped-up voltage to drive white LEDs. Unlike conventional multiple-input parallel converters, the output voltage of the proposed converter is generated by adding the output voltage of the SC-based circuit to the voltage of solar-cells. For this reason, the proposed converter can realize not only small hardware-cost but also wide input-range. Concretely, in comparison with the conventional parallel converter using 1.5 × step-up SC converters, the proposed converter can achieve 20% reduction of hardware cost and 16% extension of input range. The characteristics of the proposed converter are clarified by theoretical analyses. Furthermore, SPICE simulations and experiments show the validity of circuit design, where theoretical results correspond well with simulation results. For this reason, derived theoretical formulas can provide basic information to design serial SC DC-DC converters. The proposed converter will be useful as a LED driver circuit for display back-lighting. © 2011 ICIC International.
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Design of an inductor-based wled driver using clean energy power supplies
(2010-10-01)
Eguchi, Kei
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Pongswatd, Sawai
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Watanabe, Toshiya
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Zhu, Hongbing
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Tirasesth, Kitti
For mobile back-lighting applications, a dual-input white LED (WLED) driver using a bi-direction buck-boost converter is proposed in this paper. The proposed driver has two input terminals: lithium battery input V<inf>in1</inf> and solar-cell input V<inf>in2</inf> Unlike conventional drivers using boost converters, step-up SC DC-DC converters, and so on, the proposed converter drives the anode and the cathode of LEDs by using the solar-cell's voltage and the negative stepped-down voltage, respectively. Furthermore, by converting solar energy, the proposed converter can charge the lithium battery when the LED back-light is off. Therefore, the proposed converter can realize long battery runtime. The validity of the proposed converter is confirmed by simulations and experiments. ICIC International © 2010 ISSN.

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