Fully organic solid state tissue equivalent radiation dose (SSTED) detector (Conference Presentation)

Channel-restricted meniscus self-assembly for uniformly aligned growth of single-crystal arrays of organic semiconductors

The use of organic materials as radiation detectors has grown, due to the easy processability in liquid phase at room temperature and the possibility to cover large areas by means of low cost deposition techniques. Direct charged-particle detectors based on solution-grown Organic Semiconducting Single Crystals (OSSCs) are shown to be capable to detect charged particles in pulse mode, with very good peak discrimination. The direct charged-particle detection in OSSCs has been assessed both in the planar and in the vertical axes, and a digital pulse processing algorithm has been used to perform pulse height spectroscopy and to study the charge collection efficiency as a function of the applied bias voltage. Taking advantage of the charge spectroscopy and the good peak discrimination of pulse height spectra, an Hecht-like behavior of OSSCs radiation detectors is demonstrated. It has been possible to estimate the mobility-lifetime value in organic materials, a fundamental parameter for the characterization of radiation detectors, whose results are equal to μτcoplanar = (5 .5 ± 0.6 ) × 10−6 cm2/V and μτsandwich = (1 .9 ± 0.2 ) × 10−6 cm2/V, values comparable to those of polycrystalline inorganic detectors. Moreover, alpha particles Time-of-Flight experiments have been carried out to estimate the drift mobility value. The results reported here indicate how charged-particle detectors based on OSSCs possess a great potential as low-cost, large area, solid-state direct detectors operating at room temperature. More interestingly, the good detection efficiency and peak discrimination observed for charged-particle detection in organic materials (hydrogen-rich molecules) are encouraging for their further exploitation in the detection of thermal and high-energy neutrons.

Organic semiconductors (OSCs) have attracted growing attention for optoelectronic applications such as field-effect transistors (FETs), and coherent (or band-like) carrier transport properties in OSC single crystals (SCs) have been of interest as they can lead to high carrier mobilities. Recently, such p-type OSC SCs compatible with a printing technology have been used to achieve high-speed FETs; therefore, developments of n-type counterparts may be promising for realizing high-speed complementary organic circuits. Herein, coherent electron transport properties in a printed SC of a state-of-the-art, air-stable n-type OSC, PhC2 -BQQDI, by means of variable-temperature gated Hall effect measurements and X-ray single-crystal diffraction analyses in conjunction with band structure calculations, are reported. Furthermore, the SC FET is tested for high-speed operations, which obtains a cutoff frequency of 4.3MHz at an operation voltage of 20V in air. Thus, PhC2 -BQQDI is shown as a new candidate for practical applications of SC-based, organic complementary devices.

Abstract2D organic semiconductor single crystals comprising one or a few molecular layers of macroscopic lateral sizes are ideal materials for ultrathin, flexible, and transparent field‐effect devices—a platform for transistors and sensors. In recent years, these 2D materials have demonstrated high performance not inferior to their 3D counterparts. However, light emissive properties of 2D organic semiconductor single crystals have not yet been reported, and a combination of high charge‐carrier mobility and bright luminescence in one material is still a challenge for 2D organic optoelectronics. Emissive high‐mobility 2D organic semiconductor based on a [1]benzothieno[3,2‐b]benzothiophene (BTBT)‐derivative, 2,7‐bis(4‐decylphenyl)[1]benzothieno[3,2‐b][1]benzothiophene (DPBTBT), is presented here. DPBTBT molecules self‐organize in large‐area ultrathin single‐crystalline films consisting of one or a few molecular layers. These 2D single crystals perfectly suit as an active layer of organic field‐effect transistors in full accordance with Shockley's model and uniquely combine the high charge‐carrier mobility reaching 7.5 cm2 V–1 s–1 with prominent light emissive properties, which allow a demonstration of the first 2D organic light‐emitting transistor. The high charge‐carrier mobility and thermal stability of the crystalline phases, pronounced luminescence, and good shelf‐life stability suggest that emissive BTBT‐type molecules are a promising avenue for 2D organic optoelectronics.

Polarization, a fundamental property of light, encodes unique information critical for technological innovations such as bionic navigation, anti‐interference imaging, and secure communication. Conventional polarization‐sensitive materials suffer from inherent limitations, including low linear dichroism, complex fabrication processes, and bulky device integration. Organic semiconductors single crystals (OSSCs) have emerged as a transformative alternative, leveraging intrinsic structural anisotropy from long‐range ordered molecular packing, tunable optical and charge‐transport synergy, and low‐cost solution processability. This perspective systematically elaborates on the core merits of OSSCs for polarization perception, focusing on their intrinsic molecular packing anisotropy, polarization‐dependent optical absorption, and charge transport features. We then highlight recent breakthroughs in OSSC‐based polarization‐sensitive devices, encompassing high‐performance polarization photodetectors, biomimetic polarization vision systems, advanced polarization imaging, and encrypted communication. Furthermore, future directions for advancing OSSCs, including materials engineering, scalable patterned growth of OSSCs, and multifunctional integration, are subsequently outlined. This perspective aims to inspire the great potential of OSSCs for driving transformative progress in next‐generation polarization‐enabled technologies and unlock new possibilities in flexible wearables, autonomous robotics, and energy‐efficient intelligent perception systems.

Hybrid lead halide perovskites are introduced as charge generation layers (CGLs) for the accurate determination of electron mobilities in thin organic semiconductors. Such hybrid perovskites have become a widely studied photovoltaic material in their own right, for their high efficiencies, ease of processing from solution, strong absorption, and efficient photogeneration of charge. Time-of-flight (ToF) measurements on bilayer samples consisting of the perovskite CGL and an organic semiconductor layer of different thickness are shown to be determined by the carrier motion through the organic material, consistent with the much higher charge carrier mobility in the perovskite. Together with the efficient photon-to-electron conversion in the perovskite, this high mobility imbalance enables electron-only mobility measurement on relatively thin application-relevant organic films, which would not be possible with traditional ToF measurements. This architecture enables electron-selective mobility measurements in single components as well as bulk-heterojunction films as demonstrated in the prototypical polymer/fullerene blends. To further demonstrate the potential of this approach, electron mobilities were measured as a function of electric field and temperature in an only 127 nm thick layer of a prototypical electron-transporting perylene diimide-based polymer, and found to be consistent with an exponential trap distribution of ca. 60 meV. Our study furthermore highlights the importance of high mobility charge transporting layers when designing perovskite solar cells.

We present the first reported instance of an image-charge detector for charged particles in which detection elements are patterned onto printed circuit boards. In contrast to conventional techniques involving separately machined and positioned segments of metal tubing, this technique is much simpler to assemble, align, and connect to electrical wiring, with no loss in sensitivity. The performance of single-stage and 5-stage charge detectors is demonstrated using electrospray-charged, micrometer-size polystyrene spheres. Both velocity and charge of each particle are measured. Multiple detection stages--which require no extra effort to pattern or setup compared with a single stage--result in an ensemble averaging effect, improving the detection limit over what can be achieved with a single-stage detector. A comparison is made between the printed circuit board detector and a conventional tubular charge detector and found to be statistically equivalent. These results demonstrate and illustrate that devices for detection, analysis, and/or manipulation of charged particles and ions can be made using printed circuit boards rather than using separately fabricated metal electrodes.

Tetrabenzoporphyrin (BP) is a p-type organic semiconductor characterized by the large, rigid π-framework, excellent stability, and good photoabsorption capability. These characteristics make BP and its derivatives prominent active-layer components in organic electronic and optoelectronic devices. However, the control of the solid-state arrangement of BP frameworks, especially in solution-processed thin films, has not been intensively explored, and charge-carrier mobilities observed in BP-based materials have stayed relatively low as compared to those in the best organic molecular semiconductors. This work concentrates on engineering the solid-state packing of a BP derivative, 5,15-bis(triisopropylsilyl)ethynyltetrabenzoporphyrin (TIPS-BP), toward achieving efficient charge-carrier transport in its solution-processed thin films. The effort leads to the selective formation of a brickwork packing that has two dimensionally extended π-staking. The maximum field-effect hole mobility in the resulting films reaches 1.1 cm2 V-1 s-1, which is approximately 14 times higher than the record value for pristine free-base BP (0.070 cm2 V-1 s-1). This achievement is enabled mainly through the optimization of three factors; namely, deposition process, cast solvent, and self-assembled monolayer that constitutes the dielectric surface. On the other hand, polarized-light microscopy and grazing-incident wide-angle X-ray diffraction analyses show that there remains some room for improvement in the in-plane homogeneity of molecular alignment, suggesting even higher charge-carrier mobilities can be obtained upon further optimization. These results will provide a useful basis for the polymorph engineering and morphology optimization in solution-processed organic molecular semiconductors.

The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering. Organic semiconductors are emerging as viable materials for low-cost electronics and optoelectronics, such as organic photovoltaics (OPV), organic field effect transistors (OFETs), and organic light emitting diodes (OLEDs). Despite extensive studies spanning many decades, a clear understanding of the nature of charge carriers in organic semiconductors is still lacking. It is generally appreciated that polaron formation and charge carrier trapping are two hallmarks associated with electrical transport in organic semiconductors; the former results from the low dielectric constants and weak intermolecular electronic overlap while the latter can be attributed to the prevalence of structural disorder. These properties have lead to the common observation of low charge carrier mobilities, e.g., in the range of 10-5 - 10-3 cm2/Vs, particularly at low carrier concentrations. However, there is also growing evidence that charge carrier mobility approaching those of inorganic semiconductors and metals can exist in some crystalline organic semiconductors, such as pentacene, tetracene and rubrene. A particularly striking example is single crystal rubrene (Figure 1), in which hole mobilities well above 10 cm2/Vs have been observed in OFETs operating at room temperature. Temperature dependent transport and spectroscopic measurements both revealed evidence of free carriers in rubrene. Outstanding questions are: what are the structural features and physical properties that make rubrene so unique? How do we establish fundamental design principles for the development of other organic semiconductors of high mobility? These questions are critically important but not comprehensive, as the nature of charge carriers is known to evolve as the carrier concentration increases, due to the presence of intrinsic disorder in organic semiconductors. Thus, a complementary question is: how does the nature of charge transport change as a function of carrier concentration?

Impact of gamma-ray irradiation on the electronic structures of PCBM and P3HT organic semiconductor films

The transmission laser soldering technology described in this paper enables the realization of rigid - flexible interconnection after mass reflow soldering of the surface mount components to the rigid printed circuit board (PCB). The novelty of our approach is that the solder paste is heated up selectively by an Nd:YAG laser through the flexible substrate, which is in most cases polyimide (PI). The amount of transmitted laser energy can be controlled and concentrated so precisely to the metallic parts (pad and solder), that it enables the application of solder paste with higher melting point as the temperature tolerance of the flexible substrate, thus solder joints can be formed on polyethylene-terephtalate (PET) and polyethylene-naphtalate (PEN) substrates as well. The paper describes the transmission laser soldering process parameters used for PI, PET and PEN substrates and SnAgCu and SnBi solders. The metallographic analysis and the pull strength measurement results are also presented. Based on our experiments it can be stated that our laser soldered joints of rigid to flexible printed circuits show similar quality and reliability properties to the reflow soldered ones.

Advanced electronic packaging materials play a key role in the proper functioning and useful life of the packaged electronic assembly. These functions mainly include electrical conduction, electrical insulation, mechanical support and structural profiles, environmental protection, as well as thermal conduction and dissipation. Therefore, electronic packaging materials shall possess required electrical, mechanical, thermal, chemical, and physical properties to provide the electronic system with excellent performance and reliable functions. For example, metals provide the means for conducting signals throughout the system via thin-film conductors, wires, interconnects, vias, etc.; insulating materials are used to prevent loss of signal currents by confining them to the metal path; structural or multifunctional materials are used to provide physical functions and mechanical support; and there are materials in which the primary function is for thermal dissipation or to prevent the system from the environment. This chapter will provide an overall review for the state of the art of high-performance electronic packaging materials and their thermal management functions, including properties of key materials, state of maturity, applications, processing, and future directions. These materials mainly include metallic materials, ceramics and semiconductors, electronic glasses, polymers, multimaterial laminates, printed circuit board (PCB) materials, thermal interconnection materials, low thermal conductivity materials, and advanced thermally conductive materials.

A fully inkjet-printing technology is applied to antenna-in-package (AiP) and substrate integrated waveguide (SIW) to enhance the performance of three components, including via holes, wire bonding, and flexible antenna arrays. First of all, earlier studies utilize shorting pins for the conductive pathway in high-density AiP and SIW, but this requires an additional procedure to plate the conductor. We propose a mechanical approach to form a cylindrical hole, plating the surface with silver nanoparticles and realizing the equivalent circuit model of the shorting pin. The proposed approach does not require high alignment sensitivity or the precise control of laser power level. Second, fully inkjet-printed wire bonding is proposed for the system on the package. The proposed technique not only reduces the discontinuity but also enables a fabrication without additional assembly. Third, the proposed technique is implemented for antenna development, which shows desirable performance with reduced fabrication complexity. The proposed technology is validated by microstrip lines, SIWs, SIW cavity slots, and flexible 4 × 4 patch arrays fabricated on various substrates including RO 4003C, polyimide, and polyethylene naphthalate. For comparison purposes, conventional approaches using printed circuit boards are also implemented and tested. The results indicate the generality and capability of the proposed technique.

Laser beam has a thermal effect on the exposed body through oscillation of molecules. Rate of the vibrations depend on the time of exposure, intensity of the laser beam, the quantity of the absorbed dose, and the laser wavelength. Impacts of green laser beam on the hematological parameters of Albino Rats investigated in an in-vivo irradiation process. Green laser (200mW, 532nm) was used as a source of non-ionizing radiation to irradiate albino rats, the exposure carried out to heart position (in-vivo) of the rats directly. Fifteen female rats participated. Main blood components: white blood cells (WBC), red blood cells (RBC), and platelet (PLT) counts were evaluated using a direct exposure method for low and high radiation doses. High doses of laser beam affected the WBCs and PLTs significantly (P-value < 0.05), and the low doses were not significant (P-value > 0.05). Laser beam radiation affected on the main blood components at a limited time of exposure. Optimum radiation doses that had high effectiveness on blood component density depended on the type of blood components. As well as, high impacts (high significant) were on the density of PLT not RBCs. References FARHAD H M, JAAFAR M S, ISMAIL A H.( 2011). Control Light Delivery in PDT by Taking Account the Optical Properties of Hair Density on the Skin Surface. Journal of Modern Applied Science. 2 p.325-331. HUDA K.M., (2017). The effects of laser radiation on viscosity (PCV) of blood. Pak.J.Biotechnol . Vol.14, No.3 , pp.477-479. ISMAIL A. H., AND ABDULLA K. N., (2021). Biochemical and hematological study of the effects of annual exposure radiation doses on the operators of X-ray and CT-scan in some Erbil hospitals. Radiation Physics and Chemistry, Vol.184, 109466 KUTSCH, V. K. (1993). Laser in Dentistry. Jour. Amer. Dent. Asso. 124: 49-54. MARKOLF, H. N. (1996). Laser Tissue Interaction. Heidelberg, Germany. MUSTAFA S. AL MUSAWI, M. S. JAAFAR, B. AL-GAILANI, NASER M. AHMED, FATANAH M. SUHAIMI & NURSAKINAH SUARDI ,Lasers in Medical Science volume 32, pages405–411(2017). MUSTAFA S.A., JAFAAR M.S., NASER M. A., AL-GAILANY B.T., FATANAH M. S., 2016. Effects of low power violet laser irradiation on red blood cells volume and erythrocyte sedimentation rate in human blood, Journal of physics; conference series, Vol.1875, 020005-1-020005-7. RAAD SH. ALNAYLI A., ZAHRAA S. S., FAID SH. H., HADEEL H. S. (2017).The Effect of LASER on Blood Viscosity and Its Influential Relation on the Rapidity of Red Blood Cells Precipitation . American International Journal of Research in Science, Technology, Engineering & Mathematics, 19(1) pp.69- 74. SITI SAKINA M. F., SUARDI N., MUSTAFA I. S., (2018). In vitro UV-visible spectroscopy study of yellow laser irradiation on human blood. Journal of physics; conference series, Vol.995, 012053. THAIHAMMER.S, LAHR. A, CLEMENT, SENGEWALD. A, HESKL. W. M, BURGEMEISTER. R, AND SCHUTZE (2003) “Laser Micro tool in Cell Biology Medicine” laser physics ,13,5. VANENKO, M. & HERING, P. (1998). Hard Tissue Ablation with Mechanically Q – Switched CO2 Laser. SPIE Proc. 3565:110 – 115. XU Q, MING Z, DART AM, DU XJVAN PELT LF. (2007). Optimizing dosage of ketamine and xylazine in murine echocardiography. Clin Exp Pharmacol Physiol. 4(5-6):499-507. ZAHRA AL- TIMIMI (2014). Investigating the Effects of Green Laser Irradiation on Red Blood Cells: Green Laser Blood Therapy. Int.Jou. of Applied Research and Studies.Vol.3, Issue 10,pp.1-5.

Surface doping in single crystal organic semiconductors