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Lead‐based halide perovskites have gained significant prominence in recent years in optoelectronics and photovoltaics, owing to their exceptional optoelectronic properties. Nonetheless, the toxicity of lead (Pb) and the stability concern pose obstacles to their potential for future large‐scale market development. Herein, stable lead‐free Cs3Bi2I9 (CBI) films are presented with smooth and compact morphologies synthesized via chemical vapor deposition (CVD), demonstrating their application as an UV photodetector in a self‐powered way. The self‐powered photodetectors (SPDs) exhibit remarkable characteristics, including a responsivity of 1.57 A W−1 and an impressive specific detectivity of 3.38 × 1013 Jones under the illumination of 365 nm at zero bias. Furthermore, the SPDs exhibit a nominal decline (≈2.2%) in the photocurrent under constant illumination over 500 h, highlighting its impressive long‐term operational stability. Finally, the real‐time UV‐detection capability of the device is demonstrated by measuring the photocurrent under various conditions, including room light and sunlight at different times. These findings offer a new platform for synthesizing stable and high‐quality perovskite films, and SPDs for advancing the development of wearable and portable electronics. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic perovskite solar cells (PSCs) are receiving huge attention owing to their marvelous advantages, such as low cost, high efficiency, and superior optoelectronics characteristics. Despite their promising potential, charge-carrier dynamics at the interfaces are still ambiguous, causing carrier recombination and hindering carrier transport, thus lowering the open-circuit voltages (Voc) of PSCs. To unveil this ambiguous phenomenon, we intensively performed various optoelectronic measurements to investigate the impact of interfacial charge-carrier dynamics of PSCs under various light intensities. This is because the charge density can exhibit different mobility and charge transport properties depending on the characteristics of the charge transport layers. We explored the influence of the hole transport layer (HTL) by investigating charge transport properties using photoluminescence (PL) and time-resolved (TRPL) to unveil interfacial recombination phenomena and optoelectronic characteristics. We specifically investigated the impact of various thicknesses of HTLs, such as 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD), and poly(triaryl)amine (PTAA), on FA0.83MA0.17Pb(Br0.05I0.95)3 perovskite films. The HTLs are coated on perovskite film by altering the HTL's concentration and using F4-TCNQ and 4-tert-butylpyridine (tBP) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSi) as dopants both for spiro-OMeTAD and PTAA. These HTLs diversified the charge concentration gradients in the absorption layer, thus leading to different recombination rates based on the employed laser intensities. At the same time, the generated charge carriers are rapidly transferred to the interface of the HTL/absorption layer and accumulate holes at the interface because of inefficient capacitance and mobility differences caused by differently doped HTL thicknesses. Notably, the charge concentration gradient is low at lower light intensities and did not accumulate holes at the HTL/absorption layer interface, even though they have high charge mobility. Therefore, this study highlights the importance of interfacial charge recombination and charge transport phenomena to achieve highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

The continuous scaling down of dynamic random access memory devices has necessitated a comprehensive understanding of the initial growth mechanism in atomic layer deposition. In this study, HfO2 was deposited using tetrakis(ethylmethylamido)hafnium (TEMAHf)-H2O on H-/OH-terminated Si (100) surfaces. By analyzing the Hf-O peak in the FTIR spectra and medium-energy ion scattering measurements, it was determined that a monolayer was formed on the H-Si surface at a rate (10 cycles) lower than that for the OH-Si surface (4 cycles). The ligand variations during each cycle, as determined by FTIR measurements, enabled the suggestion of the initial precursor adsorption mechanism. An analysis of the infrared spectra and secondary ion mass spectrometry depth profiles revealed surface-dependent differences in interfacial bonding. This explained the variation in the rate of formation of 1 Ml. Additionally, theoretical investigations using density functional theory calculations identified the reaction pathway with the lowest energy barrier, thereby validating the experimentally proposed mechanism. This study to elucidate the Si surface and the TEMAHf-H2O reaction mechanism provided insights into the analysis of the initial precursor adsorption mechanism for other types of precursors. [ABSTRACT FROM AUTHOR]

When the thickness of the solar cell wafer and the amount of Ag to be used decreases, it is the best method to recover the power of the module after use at a minimum cost and reuse the module itself. Economic recovery technology can be applied to the power degradation, caused by the resistive solder bond (RSB) hotspot by poor soldering, because the recovery process can be simplified compared to the power loss that is often greater than 30%. This study demonstrated a quick recovery of the RSB hotspot with on-site recovery technology applied with resin and verified the performance and long-term reliability of on-site recovery technology, compared to the factory recovery method, where the back sheet is removed and laminated to recover the module. Both the factory and field recovery methods confirmed recovery results closer to the initial rated power output of the samples. Each sample was degraded by the RSB hotspot to ~62–65% of the initial power output, and the recovery process successfully recovered it to ~96–99%. In on-site recovery, verification of the possible EVA solvothermal swelling, which is the effect of organic solvents contained in the resin on EVA, is essential for verifying the long-term reliability of the recovered module. In this study, the power degradations of the on-site recovered samples after a TC 200 cycle test are −2.14% and −0.95%, respectively, which are within the certification test standard of the new manufacturing module. Existing factory recovery costs not only in the recovery process, but also in a total of 22 stages, such as the transfer of the target module. The largest advantage is that the on-site recovery process can be restarted in the field after only eight stages. [ABSTRACT FROM AUTHOR]

Abstract: A systematic characterization of sub-50-μm-thick, kerf-less monocrystalline Si wafers fabricated by a controlled fracture method is presented. The spalling process introduces various defects on the Si surface, which result in high surface roughness levels, residual stress, and low effective minority carrier lifetimes. In addition, metals used to induce fracturing in Si diffuse in the Si at room temperature and degrade the effective minority carrier lifetime. Selective removal of these defected Si regions improves the residual stress and effective lifetimes of spalled Si wafers.Graphical Abstract: [ABSTRACT FROM AUTHOR]

To investigate the gettering effect of n-type (phosphorous-doped) crystalline Czochralski-silicon (Cz-Si) wafers, we made boron emitters by diffusing boron into them and, subsequently, oxidized the boron-diffused n-type crystalline silicon wafers by in situ wet and dry oxidation. After oxidation, we measured the minority carrier lifetime by using microwave photoconductivity decay (μ-PCD), open-circuit voltage by quasi-steady-static photoconductance and the sheet resistance by a 4 point probe, respectively. We suggested the boron diffusion and in situ oxidation conditions to achieve longer lifetimes. We can obtain the equivalent lifetime to conventional oxidation through the quartz tube designed for boron doping and in-situ oxidation. The uniformity of sheet resistance under 3% was achieved at relatively low temperature and the lifetime of 21.6 μs was also obtained by boron gettering effect and passivation of oxide layer. [ABSTRACT FROM AUTHOR]

The effect of electroless wet treatment on multi-crystalline silicon solar cells was investigated. We prepared nanostructures on a multi-crystalline silicon surface via wet nano-texturing processes to ensure that less light is reflected off the surface. Nano-texturing can reduce the average reflectance to about 2.5% in the wavelength range of 400-900 nm. Further, we obtained an effective reflectance of 1.9% with Al2O3/SiNx:H coating. The use of our wet nano-texturing process resulted in a reflectance value lower than that obtained with conventional acid texturization. Thus, the nano-texturing of multi-crystalline silicon via the wet chemical process can further increase the efficiency of silicon solar cells (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Charge transporting materials (CTMs) in perovskite solar cells (PSCs) have played an important role in improving the stability by replacing the liquid electrolyte with solid state electron or hole conductors and enhancing the photovoltaic efficiency by the efficient electron collection. Many organic and inorganic materials for charge transporting in PSCs have been studied and applied to increase the charge extraction, transport and collection, such as Spiro-OMeTAD for hole transporting material (HTM), TiO2 for electron transporting material (ETM) and MoOX for HTM etc. However, recently inorganic CTMs are used to replace the disadvantages of organic materials in PSCs such as, the long-term operational instability, low charge mobility. Especially, atomic layer deposition (ALD) has many advantages in obtaining the conformal, dense and virtually pinhole-free layers. Here, we review ALD inorganic CTMs and their function in PSCs in view of the stability and contribution to enhancing the efficiency of photovoltaics. [ABSTRACT FROM AUTHOR]

The thermal stability of the HfO[sub 2]–Al[sub 2]O[sub 3] laminate gate stack grown by atomic layer chemical vapor deposition was investigated using medium-energy ion scattering spectroscopy and high-resolution x-ray photoelectron spectroscopy. The laminate structure was maintained up to 800 °C under ultrahigh vacuum conditions, while it was drastically degraded at 850 °C, resulting in silicide formation on the film surface. Dissociated oxygen in the Hf–Al-oxide preferentially diffuses out through the film and desorbing at the surface. Volatile SiO species and Al–O components desorb through the sample surface, while HfO[sub 2] contributes to Hf silicide formation on the film surface. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The thermal stability of a nanolaminate (Al[sub 2]O[sub 3]/ZrO[sub 2]/Al[sub 2]O[sub 3]) gate stack prepared by atomic layer chemical vapor deposition was investigated using medium-energy ion scattering spectroscopy, and x-ray photoelectron spectroscopy. We observed that the structure was stable up to 1000 °C under ultrahigh vacuum conditions. However, annealing in a nitrogen or oxygen ambient at 1 atm yielded the formation of an interfacial Zr-Al silicate layer at much lower temperatures. The growth of the interfacial silicate layer could be significantly reduced during furnace annealing via the use of plasma nitridation. [ABSTRACT FROM AUTHOR]

The electrical and structural characteristics of an ultrathin gate dielectric, thermally grown on 4° tilted wafer has been investigated. Compared with a control wafer, a relaxation of the Si lattice strain at the SiO[sub 2]/Si(001) interface was observed for the 4° tilted wafer, which was confirmed by medium energy ion scattering spectroscopy. A significant improvement in the reliability characteristics of a metal–oxide–semiconductor (MOS) capacitor, with a 2.5-nm-thick gate oxide, grown on a tilt wafer was observed. This improvement in reliability can be explained by the relaxation of strain at the SiO[sub 2]/Si interface. An ultrathin gate dielectric grown on a tilt wafer represents a promising alternative for gate dielectric applications in future MOS devices. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials have distinct optical and electrical properties owing to their unique structures. In this study, smooth 2D amorphous tin disulfide (SnS2) films were fabricated by atomic layer deposition (ALD), and applied for the first time to photoelectrochemical water splitting. The optimal stable photocurrent density of the 50-nm-thick amorphous SnS2 film fabricated at 140 °C was 51.5 µA/cm2 at an oxygen evolution reaction (0.8 V vs. saturated calomel electrode (SCE)). This value is better than those of most polycrystalline SnS2 films reported in recent years. These results are attributed mainly to adjustable optical band gap in the range of 2.80 to 2.52 eV, precise control of the film thickness at the nanoscale, and the close contact between the prepared SnS2 film and substrate. Subsequently, the photoelectron separation mechanisms of the amorphous, monocrystalline, and polycrystalline SnS2 films are discussed. Considering above advantages, the ALD amorphous SnS2 film can be designed and fabricated according to the application requirements. [ABSTRACT FROM AUTHOR]

In this study, eco-friendly Pb-free Bi2O3–B2O3–ZnO glass frits were chosen as an inorganic additive for the Al paste used in Si solar cells. The effects of the molar ratio of Bi2O3 to B2O3 in the glass composition on the electrical resistance of the Al electrode and on the cell performance were investigated. The results showed that as the molar ratio of Bi2O3 to B2O3 increased, the glass transition temperature and softening temperature decreased because of the reduced glass viscosity. In Al screen-printed Si solar cells, as the molar ratio of Bi2O3 to B2O3 increased, the sheet electrical resistance of the Al electrode decreased and the cell efficiency increased. The uniformity and thickness of the back-surface field was significantly influenced by the glass composition. [ABSTRACT FROM AUTHOR]