Samuel C. Halim

Bio: Samuel C. Halim is an academic researcher. The author has contributed to research in topics: Conductive polymer & Electron microprobe. The author has an hindex of 5, co-authored 5 publications receiving 278 citations.

Development and characterization of custom-engineered and compacted nanoparticles as calibration materials for quantification using LA-ICP-MS

Abstract: The flame spray technique was used to produce a nano-material with a customized composition. Liquid organic precursors of Si, Ca, Ti, Mg, Fe, and Al in a concentration similar to the matrix of the well-known NIST SRM 610 glass standard were mixed with a selection of rare earth elements (Ce, Gd, Ho, and Tb), precious metals (Ag, Au, Pd, Pt, Rh, and Ru) and Pb at concentrations of approx. 400–500 mg kg−1. The liquid precursor mixture was sprayed and collected as nanopowder, compacted to pellets and analyzed by solution and laser-ablation inductively coupled plasma mass spectrometry. The bulk composition of the material was determined in several aliquots of the powder, either 25 mg or 50 mg. Electron microprobe analyses were carried out to further characterize the major element composition of the pressed nano-material. The pellet was ablated using different laser ablation systems with an aim of assessing the micro-scale homogeneity of the produced material. The manufactured material is homogeneous for major elements and REE's similar to the NIST glass (<5% RSD). However, the distribution of the PGE's showed some larger spatial variation in the order of <7.5%. In addition it is shown that contamination during production leads to heterogeneous distribution of Pb and Ag. Based on the results achieved for Ru, Rh, Pd, Au, Pt, Mg, Ti, and Fe, which are either absent or not available in sufficient concentration levels in NIST glass, it is demonstrated that flame spray synthesis allows production of suitable customized matrix-matched calibration materials for micro-analytical techniques.

Electronic devices comprising solution-processable metal oxide buffer layers

Abstract: The present invention relates to the field of electronic devices, such as organic electronics, wherein said device includes a substrate and a multitude of layers, wherein at least one of said layers is a buffer layer, wherein said buffer layer includes metal oxide nanoparticles coated with dispersant as described in the specification. The invention further provides for electronic device component and materials suitable for manufacturing such electronic devices, to specific manufacturing methods and to specific uses.

Charge transport in nanoparticular thin films of zinc oxide and aluminum-doped zinc oxide

Abstract: In this work, we report on the electrical characterization of nanoparticular thin films of zinc oxide (ZnO) and aluminum-doped ZnO (AZO). Temperature-dependent current–voltage measurements revealed that charge transport for both, ZnO and AZO, is well described by the Poole–Frenkel model and excellent agreement between the experimental data and the theoretical predictions is demonstrated. For the first time it is shown that the nature of the charge-transport is not affected by the doping of the nanoparticles and it is proposed that the Poole–Frenkel effect is an intrinsic and universally limiting mechanism for the charge transport in nanoparticular thin films with defect states within the bandgap.

An Efficient Triple‐Junction Polymer Solar Cell Having a Power Conversion Efficiency Exceeding 11%

Abstract: Tandem solar cells have the potential to improve photon conversion efficiencies (PCEs) beyond the limits of single-junction devices. In this study, a triple-junction tandem design is demonstrated by employing three distinct organic donor materials having bandgap energies ranging from 1.4 to 1.9 eV. Through optical modeling, balanced photon absorption rates are achieved and, thereby, the photo-currents are matched among the three subcells. Accordingly, an efficient triple-junction tandem organic solar cell can exhibit a record-high PCE of 11.5%.

Recent progress and perspective in solution-processed Interfacial materials for efficient and stable polymer and organometal perovskite solar cells

Abstract: In this review, we summarize the latest developments in solution-processed interfacial layers that have contributed to the significantly improved performance of polymer and perovskite solar cells (PSCs and PVSCs). The solution-processed interfacial materials, including organic electrolytes, organic–inorganic hybrids, graphene oxides (GOs), transition metal oxides (TMOs), and self-assembled functional materials, along with their integration into efficient PSCs, polymer tandem cells (PTCs), and the emerging perovskite solar cells (PVSCs) are discussed. Regarding the rapid progress of PSCs and PVSCs, strategies and perspectives of further improving solution-processed interfacial materials are also discussed to help readers understand the challenges and opportunities in transitioning from scientific curiosity into technology translation for realizing low-cost, printable, and high-efficiency flexible solar cells to address the scalability issues facing solar energy.

Fill factor in organic solar cells

Abstract: The fill factor (FF) is an important parameter that determines the power conversion efficiency of an organic solar cell. There are several factors that can significantly influence FF, and these factors interact with each other very intricately. Due to this reason, a deep understanding of FF is quite difficult. Based on the three fundamental elements in the solar cell equivalent circuit, namely series resistance, shunt resistance and diode, we reviews the research progress in understanding on FF in organic solar cells. Physics lying behind the often-observed undesirable S-shaped J–V curves is also summarized. This paper aims to give a brief and comprehensive summary on FF from a fundamental point of view.

Versatile ternary organic solar cells: a critical review

Abstract: The power conversion efficiency (PCE) of organic solar cells has been constantly refreshed in the past ten years from 4% up to 11% due to the contribution from the chemists on novel materials and the physicists on device engineering. For practical applications, a single bulk heterojunction structure may be the best candidate due to the cell with a high PCE, easy fabrication and low cost. Recently, ternary solar cells have attracted much attention due to enhanced photon harvesting by using absorption spectral or energy level complementary materials as the second donor or acceptor based on a single bulk heterojunction structure. For better promoting the development of ternary solar cells, we summarize the recent progress of ternary solar cells and try our best to concise out the scientific issues in preparing high performance ternary solar cells.

Understanding Low Bandgap Polymer PTB7 and Optimizing Polymer Solar Cells Based on It

Abstract: Solution processed single junction polymer solar cells (PSCs) have been developed from less than 1% power conversion efficiency (PCE) to beyond 9% PCE in the last decade. The significant efficiency improvement comes from progress in both rational design of donor polymers and innovation of device architectures. Among all the novel high efficient donor polymers, PTB7 stands out as the most widely used one for solar cell studies. Herein the recent development of PTB7 solar cells is reviewed. Detailed discussion of basic property, structure property relationship, morphology study, interfacial engineering, and inorganic nanomaterials incorporation is provided. Possible future directions for further increasing the performance of PTB7 solar cells are discussed.