Journal of Electronic Materials

Abstract This study investigates the synthesis of heavy-metal-free AgInS2 quantum dots (QDs) using a facile successive ionic layer adsorption and reaction (SILAR) method, exploring their application in quantum dot-sensitized solar cells (QDSSCs). The AgInS2 QDs were grown on mesoporous TiO2 via a two-stage SILAR process at room temperature. The optimization of Ag-S SILAR cycles (n) was performed to determine the ideal conditions, while the In-S SILAR cycles were held constant at seven cycles. X-ray diffraction (XRD) pattern analysis revealed an orthorhombic crystalline structure of the synthesized AgInS2 QDs. Analysis of the optical spectra revealed a reduction in the optical energy bandgap (Eg,op) of AgInS2 QDs from 2.00 eV to 1.92 eV and further to 1.78 eV as the value of n increased from 1 to 3. Employing AgInS2 QDs, a polysulfide electrolyte, and a CuS counter electrode, liquid-junction semiconductor QDSSCs were fabricated. Optimal conditions were achieved at n = 2, resulting in outstanding power conversion efficiency (PCE) of 3.57% (Jsc = 8.56 mA/cm2, Voc = 0.64 V, FF = 65.2%). Under reduced light intensity (0.25 sun), the PCE increased to 5.26%. The external quantum efficiency (EQE) spectrum of the best cells spanned 400−700 nm, maintaining a nearly constant EQE value of ~ 65% within the 400−600 nm range. Remarkably, the PCE achieved surpassed previously reported liquid-junction AgInS2 QDSSCs. These findings highlight the facile production of heavy-metal-free AgInS2 QDs through a room-temperature SILAR method and the tunable optical properties of AgInS2 QDs by controlling Ag-S SILAR cycles, revealing their potential as an efficient solar absorber. Graphical Abstract

Abstract Transparent conducting oxides (TCOs) represent a remarkable class of materials with excellent electrical conductivity and high optical transparency. This unique combination of properties makes TCOs highly desirable for various applications, particularly in optoelectronic devices such as transparent electrodes for displays, solar cells, and touchscreens. However, developing high-performance TCOs, especially p-type materials, has been a significant challenge. Achieving high electrical conductivity and optical transparency is difficult in conventional materials, as materials with a wide optical bandgap (≥ 3.1 eV) are transparent in the visible region but lack electrical conductivity, while conductive metals are opaque. Hence, the only way to induce both properties in a single material is to create non-stoichiometry and/or defects. By introducing shallow defects near the conduction band for n-type materials and the valence band for p-type materials, it is possible to enhance the conductivity of the material at room temperature. Developing efficient p-type TCOs presents significant challenges due to the intrinsic localized nature of the valence band, primarily derived from oxygen 2p orbitals. This localization leads to difficulties in achieving shallow acceptor levels, which are crucial for high hole mobility. As a result, the effective mass of holes in these materials tends to be high, limiting their electrical conductivity. Commercially available TCOs are predominantly n-type, such as Sn:In2O3, Al:ZnO, and F:SnO2, while the development of efficient p-type TCOs has lagged. In this review, we discuss the origin of p-type conductivity in TCOs and the difficulties encountered in developing efficient p-type materials. We also demonstrate the fundamental material physics of p-type TCOs, including electronic structure, doping, defect properties, and optical properties. A range of deposition techniques have been adopted to prepare TCO films, and this review provides a detailed discussion of these techniques and their relative deposition parameters. Overall, we present an up-to-date and comprehensive review of different p-type transparent conducting oxide thin films, providing insights into ongoing research and potential future directions in this field.

Abstract Metal-halide perovskite semiconductors have emerged as promising materials for the next generation of solution-processed photovoltaic devices. Controlling the morphology of perovskite films is essential for achieving high device performance. Various methods have been developed to address this, including interface engineering, anti-solvent engineering, additive-assisted deposition, and vacuum treatment. Among these, anti-solvent engineering is one of the most widely utilized techniques in one-step deposition processes to produce high-quality perovskite films. In this study, we report the impact of anti-solvent on the morphological, structural, optical, chemical composition, and electrical properties of a fabricated ITO/ \({\text{TiO}}_{2}\) /perovskite/Spiro-OMeTAD/Au device. The obtained results clearly indicate that device performance was significantly improved through the use of an anti-solvent during the deposition of the perovskite layer. This improvement is attributed to the formation of a homogeneous perovskite layer, free of pinholes, with a smoother surface and enhanced crystallinity. Therefore, using an anti-solvent-assisted one-step spin-coating approach can yield a high-quality perovskite layer with high efficiency.

Abstract A nanocomposite consisting of graphene oxide (GO), cadmium sulfide (CdS), lead sulfide (PbS), and bismuth titanate (BT) was synthesized using the hydrothermal method. The structural and morphological characteristics of the nanocomposites were determined using various techniques. A shift in the x-ray diffraction peak positions of the GO-substituted samples indicates the successful integration of GO into the cadmium sulfide/bismuth titanate (CdS/BT) and lead sulfide/bismuth titanate (PbS/BT) matrices. The UV-visible spectra of the GO-reinforced bismuth Titanate show a decrease in the band gap of the nanocomposites. The presence of peaks at 1616 cm−1 and 954 cm−1 in the Fourier-transform infrared spectroscopy spectra confirms the incorporation of GO into the CdS/BT and PbS/BT samples. The photocatalytic performance of the materials was assessed through water-splitting experiments using methanol as a sacrificial agent. The results indicate that the GO composite with PbS/BT samples achieved the highest hydrogen production yield, measuring 438.21 μmolg−1.

Abstract In this article, the electronic UV–visible absorption spectra of disperse orange 3 (C12H10N4O2) are examined in ethanol solvent at varying concentrations (10−3 M, 10−4 M, 10−5 M, 10−6 M, 20 µM, and 40 µM). Azo chromophores are used extensively in the liquid crystal industry, inkjet printing, light-controlled polymers, textiles, and pharmaceutical sectors. The molar extinction coefficient (εmax) and oscillator strength (f) corresponding to maximum absorbance λmax (443 nm) in ethanol at concentration 10−4 M were calculated as 1.35 × 104 M−1 cm−1 and 15.83 × 10−2 M−1 cm−2, respectively. The dipole moment of the considered peak was calculated as 4.45 D. Other spectral parameters of scientific importance, such as absorption cross-section and attenuation length, were also calculated as 0.32 × 10−16 cm2 and 0.027 cm, respectively. The transitions associated with absorption bands observed at 227 nm, 275 nm, and 443 nm were correlated to (primary π* ← π), (secondary π* ← π), and (π* ← n) by comparison of dye moieties. This confirmed that 10−4 M is the optimum concentration for spectroscopically investigating the dye (DO3). The quenching was observed by examining fluorescence spectra at various concentrations. The molecule being investigated unequivocally demonstrates fluorescence at 532 nm at 10−4 M concentration when excited with λex = 440 nm. This results in a notable Stokes shift (Δλ = 89 nm or Δν = 3776 cm−1), which is vital for fluorescence imaging.