This research investigates organic photovoltaic (OPV) structures using time-correlated single photon counting (TCSPC) to study time-resolved fluorescence dynamics under low injection conditions. A picosecond laser diode with a wavelength of 650 nm and a single photon avalanche diode (SPAD) are applied for excitation and detection. The measurements are performed at an irradiance of 0.011 W/cm2 (1.2 & times; 108 photons/pulse) which is sufficiently low to avoid damaging the sample. Decay characteristics are analyzed using iterative reconvolution. The samples include various absorber species and structural configurations, revealing fluorescence decay components as short as 30-500 ps. Such rapid dynamics can only be detected using conventional photodiode-based setups at much higher excitation levels. The findings indicate that while absorption spectra vary with structural properties like layer thickness, decay times are primarily determined by the absorber material. TCSPC measurements thus provide deeper insights into the recombination dynamics of organic semiconductors.

Polymers containing π-conjugated segments are a diverse group of large molecules with semiconducting and emissive properties, with strong potential for use as active layers in Organic Light-Emitting Diodes (OLEDs). Stable blue-emitting materials, which are utilized as emissive layers in solution-processed OLED devices, are essential for their commercialization. Achieving balanced charge injection is challenging due to the wide bandgap between the HOMO and LUMO energy levels. This study examines the optical and photophysical characteristics of blue-emitting polymers to contribute to the understanding of the fundamental mechanisms of color purity and its stability during the operation of OLED devices. The investigated materials are a novel synthesized lab scale polymer, namely poly[(2,7-di(p-acetoxystyryl)-9-(2-ethylhexyl)-9H-carbazole-4,4′-diphenylsulfone)-co-poly(2,6-diphenylpyrydine-4,4′-diphenylsulfone] (CzCop), as well as three commercially supplied materials, namely Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), poly[9,9-bis(2′-ethylhexyl) fluorene-2,7-diyl] (PBEHF), and poly (9,9-n-dihexyl-2,7-fluorene-alt-9-phenyl-3,6-carbazole) (F6PC). The materials were compared to evaluate their properties using Spectroscopic Ellipsometry, Photoluminescence, and Atomic Force Microscopy (AFM). Additionally, the electrical characteristics of the OLED devices were investigated, as well as the stability of the electroluminescence emission spectrum during the device’s operation. Finally, the determined optical properties, combined with their photo- and electro-emission characteristics, provided significant insights into the color stability and selectivity of each material.

A systematic investigation of optical, electrochemical, photophysical, and electrooptical properties of printable green color-emitting polymer (poly(9,9-dioctylfluorene-alt-bithiophene)) (F8T2) and spiro-copolymer (SPG-01T) was conducted to explore their potentiality as an emissive layer for wearable polymer light-emitting diode (PLED) applications. We compared the two photoactive polymers in terms of their spectral characteristics and color purity, as these are the most critical factors for wearable lighting sources and optical sensors. Low-cost, solution-based methods and facile architecture were applied to produce rigid and flexible light-emitting devices with high luminance efficiencies. Emission bandwidths, color coordinates, operational characteristics, and luminance were also derived to evaluate the device’s stability. The tuning of emission’s spectral features by layer thickness variation was realized and was correlated with the interplay between H-aggregates and J-aggregates formations for both conjugated polymers. Finally, we applied the functional green light-emitting PLED devices based on the two studied materials for the detection of Rhodamine 6G. It was determined that the optical detection of the R6G photoluminescence is heavily influenced by the emission spectrum characteristics of the PLED and changes in the thickness of the active layer.

Extensive research has been dedicated to the solution-processable white organic light-emitting diodes (WOLEDs), which can potentially influence future solid-state lighting and full-color flat-panel displays. The proposed strategy based on WOLEDs involves blending two or more emitting polymers or copolymerizing two or more emitting chromophores with different doping concentrations to produce white light emission from a single layer. Toward this direction, the development of blends was conducted using commercial blue poly(9,9-di-n-octylfluorenyl2,7-diyl) (PFO), green poly(9,9-dioctylfluorenealt-benzothiadiazole) (F8BT), and red spiro-copolymer (SPR) light-emitting materials, whereas the synthesized copolymers were based on different chromophores, namely distyryllanthracene, distyrylcarbazole, and distyrylbenzothiadiazole, as yellow, blue, and orange–red emitters, respectively. A comparative study between the two approaches was carried out to examine the main challenge for these doping systems, which is ensuring the proper balance of emissions from all the units to span the entire visible range. The emission characteristics of fabricated WOLEDs will be explored in terms of controlling the emission from each emitter, which depends on two possible mechanisms: energy transfer and carrier trapping. The aim of this work is to achieve pure white emission through the color mixing from different emitters based on different doping concentrations, as well as color stability during the device operation. According to these aspects, the WOLED devices based on the copolymers of two chromophores exhibit the most encouraging results regarding white color emission coordinates (0.28, 0.31) with a CRI value of 82.

Organometallic complexes containing reactive alkali metals, such as lithium (Li), represent a promising material approach for electron injection layers and electron transport layers (EILs and ETLs) to enhance the performance of Organic Light-Emitting Diodes (OLEDs). 8-Quinolinolato Lithium (Liq) has shown remarkable potential as an EIL and ETL when conveyed in very thin films. Nevertheless, the deposition of nano-layers requires precise control over both thickness and morphology. In this work, we investigate the optical properties and morphological characteristics of Liq thin films deposited via Organic Vapor Phase Deposition (OVPD). Specifically, we present our methodology for analyzing the measured pseudodielectric function <ε(ω)> using Spectroscopic Ellipsometry (SE), alongside the nano-topography of evaporated Liq nano-layers using Atomic Force Microscopy (AFM). This information can contribute to the understanding of the functionality of this material, since ultra-thin Liq interlayers can significantly increase the operational stability of OLED architectures.

Stable red phosphorescent materials are of high importance in OLED applications and a promising scenario relies on the organometallic emitters, such as phosphorescent dopants, constituting an effective emissive layer of OLEDs, which is usually embedded in an appropriate host matrix. Iridium (III) complexes are the most widely used dopants in Phosphorescent OLEDs because of their high internal quantum efficiency. In this work, Bis(2-(3,5-dimethylphenyl)quinoline-C,N)(acetylacetonato)iridium(III), (Ir(dmpq)2(acac)), was doped in four different small molecule host materials, such as 4,4 '-Bis(N-carbazolyl)-1,1 '-biphenyl (CBP), 1,3-Bis(N-carbazolyl)benzene (mCP), 1,1-Bis[(di-4-tolylamino) phenyl]cyclohexane (TAPC) and tris(4-carbazoyl-9-ylphenyl)amine (TCTA), with doping concentrations of 4%, 6%, and 8%. tau he net host materials and the Ir(dmpq)2(acac) were first characterized in respect of their optical and photophysical properties. Following, the doped thin films were implemented as the active layers in OLED devices, formed via the solution deposition method. It was found that OLED devices fabricated for all studied cases emit red light, a characteristic of Ir(dmpq)2(acac), with a maximum wavelength of approximately 620 nm. By exploring the different combinations between the host and the dopant, as well as the different doping concentrations, we aim to provide insights into the selection of the best per-forming host materials for PhOLEDs.

Ultrafast laser patterning is an essential technology for the low-cost and large area production of flexible Organic Electronic (OE) devices, such as Organic Photovoltaics (OPVs). In order to unleash the potential of ultrafast laser processing to perform the selective and high precision removal of complex multilayers from printed OPV stacks without affecting the underlying nanolayers, it is necessary to optimize its parameters for each nanolayer combination. In this work, we developed an efficient on-the-fly picosecond (ps) laser scribing process (P1, P2 and P3) using single wavelength and single step/pass for the precise and reliable in-line patterning of Roll-to-Roll (R2R) slot-die-coated nanolayers. We have investigated the effect of the key process parameters (pulse energy and overlap) on the patterning quality to obtain high selectivity on the ablation of each individual nanolayer. Finally, we present the implementation of the ultrafast laser patterning process in the manufacturing of fully R2R printed flexible semitransparent OPV modules with a 3.4% power conversion efficiency and 91% Geometric Fill Factor (GFF).

The purpose of this work is the investigation of white light emission by blending RGB-emitting polymers and the definition of the optimal blending weight ratio, concerning the device operation characteristics and color emission. A comprehensive study of the optical properties and optoelectronic performance of white organic light-emitting diodes (WOLEDs) based on blends of poly(9,9-di-noctylfluorenyl-2,7-diyl) (PFO), poly(9,9-dioctylfluorene-altbaenzothiadiazole) (F8BT) and poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) is reported. It was observed that using relatively low ratios, up to 5 wt% of F8BT and MDMO-PPV into the host polymer PFO, slightly affects the dielectric optical response of the blended films and the characteristic electronic absorptions of PFO. Photoluminescence (PL) studies of the blends reveal that the main mechanism is the energy transfer from PFO to F8BT constituent. However, the electroluminescence (EL) study of blends, demonstrates that, in addition to energy transfer, the individual emission of PFO, F8BT and MDMO-PPV leads to a broad emission of the produced OLED devices that covers the whole visible spectral range. As a result, an almost white emission is achieved proving the potentiality to implement such solution-processable blends for lighting applications.

We have investigated semiconducting aromatic aliphatic polyethers based on either distyrylanthracene (Polymer A) or distyrylanthracene, distyrylbenzothiadiazole and distyrylcarbazole (Terpolymer B) chromophores separated by aliphatic undecane spacers that were deposited as thin films onto PEDOT:PSS by X-ray Photoelectron spectroscopy (XPS), depth-profiling XPS, and Reflection Electron Energy Loss Spectroscopy (REELS) techniques. XPS measurements demonstrated the quality of the prepared films. They also showed that for the Terpolymer B sample there is an excess of PSS dopant in the film surface, which was further corroborated through argon ion sputtering process coupled to the XPS acquisition. N1s XPS results suggest that sulphonic groups present in the PSS molecule might interfere in the Terpolymer B backbone by protonating their nitrogen atoms. From REELS data, pi - plasmon peaks were derived for Polymer A and Terpolymer B thin films. In addition, Spectroscopic Ellipsometry and Photoluminescence Spectroscopy were applied for the evaluation and the determination of the optical properties as well as the thickness of the photoactive polymeric films and the emission characteristics, respectively.

In this study, novel copolymers consisting of blue and red chromophores are presented to induce emission tuning, enabling the definition of white light emission in a single polymeric layer. These aromatic polyether sulfones exhibit high molecular weights, excellent solubility and processability via solution deposition techniques. In addition, by carefully controlling the molar ratios of chromophores composition, the energy transfer mechanism, from blue to red chromophores, takes place enabling us to define properly the emission covering the entire range of the visible spectrum. The optical and photophysical properties of the monomers and copolymers were thoroughly investigated via NIR-Vis-far UV Spectroscopic Ellipsometry (SE), Absorbance and Photoluminescence (PL). These copolymers are used as an emissive layer and applied in solution-processed WOLED devices. The fabricated WOLED devices have been subsequently studied and characterized in terms of their electroluminescence properties. Finally, the WOLED devices possess high color stability and demonstrate CIE Coordinates (0.33, 0.38), which approach closely the pure white light CIE coordinates.

White Organic Light-Emitting Diodes (WOLEDs) have attracted an enormous interest because they can be implemented in numerous lighting applications as next-generation light sources. In this work, terpolymers bearing blue, yellow and red chromophores are used for the fabrication of WOLED devices. These systems provide easy tuning of white color by changing weight ratios between the chromophores. The optical and opto-electronic characterization is carried out by near infrared–visible-far ultraviolet (NIR–Vis–FUV) Spectroscopic Ellipsometry (SE), Photoluminescence (PL), and Electroluminescence (EL), whereas the structural characterization is achieved by Atomic Force Microscopy (AFM), to provide valuable information toward the optimization and functionalization of these WOLED devices.

In the present study, spray-coated blends of 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-PEN) with Polystyrene (PS) insulating polymer were employed to improve the performance of spray-coated neat TIPS-PEN Organic Field-Effect Transistors (OFETs) on plastic substrates. By combining TIPS-PEN with PS insulating polymer, control over the TIPS-PEN crystallization behavior can be achieved. A surface morphology study on the TIPS-PEN blended with PS films at an optimized weight ratio of 0.8:0.2 was carried out, in order to investigate the phase separation phenomena between the two components within the blend. The crystallinity and the crystalline characteristics of the sprayed TIPS-PEN:PS blend films were also investigated and compared to those of the sprayed neat TIPS-PEN films. Finally, these improved characteristics of the blend-based films are correlated with the extracted electrical parameters (mobility value, on/off current ratio, threshold voltage value) of the sprayed TIPS-PEN:PS blend OFETs and are compared with those of the sprayed neat TIPS-PEN OFETs, both in terms of values and inter-device uniformity.

Greenhouse agriculture is a high-growth and high-volume market that rapidly expands worldwide to address the societal needs for food production. The increasing demand for energy to cover their requirements, coupled with the limited amount of available fossil fuels, has turned the agriculture community in the exploitation of renewable energy sources. Intensive research is currently focuses on the use of solar energy in agriculture constructions. Organic Photovoltaics (OPVs) are constantly gaining ground among other PV technologies due to their low weight, tunable optical transmittance, flexibility and high conformability. In this work, semi-transparent OPVs based on the blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) were integrated on the rooftop of the 24 m2 experimental Mediterranean greenhouse covering the 22% of its total area in order to investigate its effect on the growth and behavior of cultivated pepper plants (Capsicum annuum). Under the shade of OPVs, the pepper plants produced 20.2% more fruit mass compared to the control ones. In addition, at the end of the growing season, the height of the shaded plants was 21.8% larger than the remaining plants.

Flexible organic electronics is a rapidly emerging scientific and technological sector that is expected to develop advanced materials and devices with novel functionalities and optoelectronic performance in conformable formulations and designs. Nevertheless, the implementation of OE devices in products that can be commercially exploited requires a reliable manufacturing over large areas of devices with reproducible nanoscale quality, performance, and stability. In this chapter, we will describe the novel approach for the implementation of in-line optical metrology methods for the robust and real-time investigation of the optical, electronic, and structural properties and homogeneity of roll-to-roll (R2R) printed nanomaterials for organic photovoltaic devices during their manufacturing and their laser patterning by ultrafast laser patterning methods.

Flexible Organic Field-Effect Transistors (OFETs) constitute nowadays a highly promising field of the organic and printed electronics due to their multiple applications (flexible displays, sensors etc.). However, their cost-effective fabrication by large area Roll-to-Roll compatible printing methods still remains a challenge for their integration to commercial products. In this work, the moderate speed (1 m/min) process of the flexible cross-linked Poly(4-vinyl phenol) (PVP) polymer gate dielectric layer was carried out by integrating a slot-die method that mimics the Roll-to-Roll (R2R) coating conditions, in combination to an airbrush spray method for the solution-processing of the 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-PEN) organic semiconductor. Particularly, the PVP dielectric was slot-die-coated over a 90 x 15 cm(2) substrate, while subsequently the TIPS-PEN semiconductor was sprayed onto the 15 x 20 mm(2) cPVP-patterned plastic substrates. A surface investigation study on the well-formed slot-die-coated cPVP strips was conducted, revealing desirable dielectric film topography as a result of the good control over the coating process. A detailed analysis of the cPVP thickness evolution along the 90 x 1.3 cm(2) patterned stripe, was carried out. The morphological analysis of the sprayed TIPS-PEN layer over the cPVP film revealed well-organized large crystalline domains across the channel area, as a result of the sufficient crystallization time and the excellent cPVP surface morphology. The fabricated bottom gate/top contact flexible OFETs exhibited excellent I-V electrical characteristics with a maximum mobility of 0.21 cm(2)/V, negligible hysteresis, low threshold voltages (average value of - 0.1 V) and on/off current ratios in the range of 10(3) to > 10(4). These results demonstrate the potentiality of the proposed scalable methods for the large scale fabrication of high performance low-cost OFET devices.

Although metallic nanostructures in solar cells provide versatility in designing useful plasmonic architectures, understanding is still limited on how to exploit their multi-scale contribution as tunable performance. In this article, we suggest a characteristic model that develops into a simple and robust tool for guiding optimization of plasmonic solar devices. The model is conceptually based on the breakdown of the active region into intrinsic and plasmonic sub-circuits, by which the terminal currents are directly correlated with particle geometries and local improvement. Measurements from organic cells support the validity of our theory, and a series of simulation provides further insights into the critical trade-off between voltage and current generation, finally offering a strategy for efficiency enhancement.

Background: LCNCL is a newly recognized clinicopathologic entity, characterized by the cell morphology and the immunohistochemical evidence of neuroendocrine markers. The optimal treatment for LCNCL is not yet established. The aim of our study was to describe the clinicopathologic findings, the outcome and treatment toxicity in LCNCL patients (pts). Methods: Twenty-five pts (4%), smokers (<40 pack/year), with LCNCL, among 585 with small cell lung cancer (SCLC), were admitted & treated consecutively in our Unit between 1/1996–12/2017. Patients' characteristics are shown in the Table. The presenting symptoms, at diagnosis were cough ± heamoptysis ± fever, dyspnea, Superior Vena Cava Syndrome (SVC), bone pain ± subcutaneous nodules & chest pain in 8 (32%), 5 (20%), 4 (16%), 3 (12%) pts, while 5 (20%) absolutely asymptomatic, were diagnosed during routine check-up. Paraneoplastic tetraplegy & myopathy had 1 (4%) and 1 (4%) pts. Eight (32%) pts underwent curative surgery (5 lobectomy, 3 pneumonectomy), while the diagnosis in other pts was established by biopsy of enlarged cervical lymph nodes in 2 (8%), liver biopsy in 1 (4%), adrenal biopsy in 1 (4%) and confirmed by bronchoscopy in all cases. 17 stage IV pts had, at presentation, metastases in: liver, bones, adrenals, CNS, lung and breast in 7 (41%), 8 (47%) 5 (29%), 4 (24%) & 1 (6%) cases.Tabled 1No of pts25Median (m) age66 (33–77)ysMen/Female19/6ECOG04 (16%)114 (56%)23 (12%)34 (16%)40 (0%)Histologypure LCNCL21 (84%)Mixed LCNCL-SCLC4 (16%)cStageIb1 (4%)IIa1 (4%)IIb1 (4%)IIIa4 (16%)IIIb1 (4%)IV17 (68%)Ki-67 (%)60 (40–90%)NSE (+)25 (100%)TTF-1 (+)24 (96%)Chromogranine/Synaptophysin (+)24 (96%)CK7 (+)25 (100%)CD56 (+)25 (100%) Open table in a new tab Results: All pts received Cisplatin-Etoposide ± mediastinal ± cranial RT. Response Rate was documented in 20 (80%), median PFS was 8 (2-93+) months (mo) and OS 12 (4-93+) mo. In median follow up of 1 (1+–93+) mo, 22 (88%) died. Still alive are 3 (12%) patients. One (4%) patient, pT2N2 IIIA underwent left upper lobectomy & then received adjuvant chemotherapy + mediastinal RT + prophylactic cranial irradiation (PCI). He is still alive after 93+ mo. The other 2 with stages IIIA and IV with limited bone disease are in very good partial response for 33+ and 36+ mo. The mPFS and mOS for stages ≤ IIIA and IIIB + IV are 9 vs 3 and 16 vs 6 mo. Grade III & IV febrile leukopenia, thrombocytopenia & anemia had 4, 2 and 2 patients respectively. Conclusions: (1) LCNCL is an unusual type of lung carcinoma with strong correlation with smoking. (2) Surgery seems to be beneficial for early stage disease, but on it's own it doesn't appear to be sufficient & adjuvant chemotherapy consisting of Cisplatin/Etoposite±RT is considered mandatory. Legal entity responsible for the study: Vaslamatzis Michael Head of the Oncology Department Evangelismos General Hospital Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest.

Background: Long-term survival for patients with metastatic melanoma (MM) was very rare until the advent of targeted and checkpoint inhibitor therapy. Today clinical trial data provide evidence of encouraging 3-year and even 5-year survival rates, while real-world data are lacking. Methods: Patient and disease characteristics were collected among MM patients treated in a reference oncology center since 2012 with targeted and/or checkpoint inhibitor agents. We defined long-term survivors as patients with survival >2years from MM diagnosis; biological material was collected for genomic analyses. Results: From 130 MM patients treated with BRAF/MEK inhibitors and/or anti-CTLA4, anti-PD1 agents in any line, 25 long-term survivors were identified (19,2%), 15 men/ 10 women. Long-term survival was characterized by good prognosis features at initial diagnosis: median PS 0, normal LDH (60%), low disease burden (≤3 metastatic sites, 88%), median Distant Metastasis Free Interval (DMFI) 3 years (range 0-23+ years), 16/25 BRAF mutant MM. All long-term survivors had achieved an objective response (complete/partial) to targeted or immuno- therapy. Objective response was associated with long-term survival regardless of treatment line. Complete responses to targeted or immunotherapy are still ongoing (2 to immunotherapy >3 years, 2 to BRAF/MEKi >5 years). Most patients are alive today (21/25, 84%): 9 patients (36%) survive >5 years from MM diagnosis, with 8 of them (32%) surviving >5 years from new therapy initiation (targeted or immuno). The majority of patients (22/25, 88%) survive >3 years from initial MM diagnosis and 76% survive >3 years from therapy initiation (targeted or immuno-), suggesting that the long-term survival benefit is due to the new therapy. Genomic analysis will complement the clinical characteristics of long-term survival. Conclusions: A significant number of patients with MM treated in a reference center achieved long-term survival with targeted or immuno-therapy. The specific clinical and genomic characteristics of these long-term survivors can improve our understanding of the biological behaviour of the disease but also assist the optimal choice and use of new therapies. Legal entity responsible for the study: Oncology Department, Metropolitan Hospital, Athens. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.

Incorporating plasmonic nanoparticles in organic photovoltaic (OPV) devices can increase the optical thickness of the organic absorber layer while keeping its physical thickness small. However, trade-offs between various structure parameters have caused contradictions regarding the effectiveness of plasmonics in the literature, that have somewhat stunted the progressing of a unified theoretical understanding for practical applications. We examine the optical enhancement mechanisms of practical PCDTBT:PC70BM OPV cells incorporating metal nano particles. The plasmonic near- and far-field contributions are differentiated, with spectrum- and space-wide current enhancements found in the plasmon scattering regime and spectrum- and space-specific current enhancements in the near-field regime. A remarkable system complexity is revealed, where the plasmonic enhancement trends change and even reverse by simple changes in the device geometry. This accounts for many of the contradictory results published in the literature on plasmonic effects in OPVs. By exploring the full structural parameter phase-space we are able to now propose a unified representation that intuitively explains literature findings and trends. Our results show that an already optimized PCDTBT:PC70BM cell can be further optically enhanced by plasmonic effects by at least 20% with the incorporation of Ag nanoparticles.