As classical silicon electronics approach the physical
limits of Moore’s Law and the global energy transition
demands rapid advancements in solar photovoltaics, organic
semiconductors have emerged as a distinct material class to
address both challenges.
Organic solar cells (OSCs) offer unique advantages over
silicon photovoltaics, including mechanical flexibility,
solution-based processing, and tunable optical properties.
This study focuses on the intrinsic characteristics of
organic materials that directly influence solar cell
performance, specifically addressing recent trends in
thickness-insensitive devices and donor/acceptor (D/A)
interface orientation. In light of these advancements, the
authors previous findings are reviewed and their
implications are highlighted. Prior investigations
analyzing P3HT:PCBM based OSCs with different active layer
thicknesses (ALTs) operating in both photodetector and
solar cell modes was reconsidered. A comprehensive
drift–diffusion model was utilized to reproduce
experimental photocurrent spectra and current
density-voltage characteristics. The research demonstrated
a non-monotonic variation of optical and electrical
parameters with ALT, revealing strong and tight correlation
between film thickness and morphology. Furthermore,
comparable performance between bilayer and bulk
heterojunction (BHJ) devices challenges the common
assumption that BHJ materials function as a single
effective medium. Instead, the findings indicate that
spatial arrangement and domain orientation strongly
influence charge carrier photogeneration and recombination,
proving that BHJ materials must be treated as ensembles of
D/A interfaces rather than homogeneous layers.

This study examined the adhesion between anodized aluminum
alloy 7075 and epoxy adhesive, focusing on extending the
adhesive's service life. Characterization methods included
Vickers microhardness (HV), Atomic Force Microscopy (AFM),
Owens-Wendt-Rabel-Kaelble (OWRK) analysis, and shear
testing. Results showed that non-anodized samples with
epoxy had the highest HV values. AFM confirmed that
anodization increases surface roughness, while the epoxy
formed a uniform, defect-free film. OWRK analysis indicated
that epoxy-coated samples had the highest surface energy,
dominated by the polar component, confirming hydrophilicity
and favorable adhesion. Shear testing revealed that
anodized and primed samples bonded with epoxy beyond its
nominal service life achieved the highest shear stress,
demonstrating the potential to extend adhesive usability.
The adhesion parameter b was also the highest for anodized
and primed samples, confirming superior bonding
performance. Overall, anodization combined with priming
enhanced adhesion and supported the sustainable extension
of epoxy adhesive service life.

Boron co-doping is employed to optimize microstructure
and trap distribution in CaSnO₃:Cr³⁺,Gd³⁺,Na⁺ phosphors for
enhanced
near-infrared (NIR) persistent luminescence. The addition
of boron
induces liquid-phase sintering, leading to grain growth
(~32 μm) and
a ~40% increase in photoluminescence intensity. The
optimized
composition with 4 at.% B shows improved emission and energy
storage characteristics of the material. Decay analysis (n
≈ 0.97)
reveals a tunneling-controlled recombination mechanism,
while trap
engineering extends the afterglow beyond 2 h. The results
demonstrate
that combining boron-assisted microstructural control with
Gd³⁺/Na⁺-
mediated crystal-field and defect engineering is an
effective route to
high-performance NIR persistent phosphors.

The design of polymer-ceramic composites with tunable
optical response remains a challenge in advancing efficient
and adaptable optoelectronic materials. In this work, we
report an investigation of poly(methyl methacrylate) (PMMA)
composites reinforced with yttrium aluminum garnet (YAG)
particles, focusing on the coupling between garnet-based
emitters and transparent polymer matrix at low filler
loadings. High-purity YAG with controlled submicron
particle size distribution was incorporated into PMMA via
solution processing, enabling uniform dispersion and
preservation of structural integrity. Comprehensive
characterization using electron microscopy, diffraction
analysis and infrared spectroscopy confirms phase purity,
high crystallinity and subtle interfacial interactions that
do not disrupt the polymer backbone but induce measurable
vibrational shifts. Most importantly, time-resolved
fluorescence analysis reveals an enhancement of emission
intensity accompanied by a red shift and spectral
broadening in PMMA-YAG composites compared to pristine
PMMA. This behavior indicates synergistic light-matter
interactions arising from the hybrid structure. The results
demonstrate that even minimal YAG incorporation can
effectively modulate optical emission pathways, offering a
controllable strategy for tailoring photonic responses.
These findings provide new insight into the
structure-property relationships in polymer-garnet systems
and establish PMMA-YAG composites as promising candidates
for next-generation light-emitting and photonic devices,
where tunability, processability and optical efficiency are
simultaneously required.

This paper studies the field-dependent microwave response
of an amorphous soft ferromagnetic alloy sample (ribbon or
microwire) measured in a vector network analyzer (VNA) and
test-fixture (TF) system. The results indicate that the
apparent negative real part of impedance should not be
interpreted as a true intrinsic negative resistance of the
sample, but rather as a resonance-related effect associated
with ferromagnetic resonance and the reference-based VNA/TF
measurement procedure. To further clarify this phenomenon,
attenuation curves reported in the literature were
digitized, reconstructed, and used to synthesize the
corresponding microwave S-parameter response. The influence
of embedding and de-embedding conditions on the field
sensitivity was analyzed. TF can modify the resonance
region and significantly change magnetic-field sensitivity.
In the analyzed case, the best result was obtained for a
configuration with one cascaded TF section and grounded
opposite side of the coaxial sample, yielding a sensitivity
improvement of about 670% compared with the standalone
synthesized response.

U ovom radu vršeno je ispitivanje specifične električne
otpornosti (ρ) i temperaturnog koeficijenta specifične
električne otpornosti (α) BaTiO3 keramike dopirane
holmijumom. Koncentracija jona Ho3+ kretala se od 0.01 at%
do 1.0 at%. Uzorci su pripremljeni konvencionalnom metodom
sinterovanja u čvrstom stanju i sinterovani na temperaturi
od 1320 °C. Analiza mikrostrukture pokazala je da
koncentracija dopanta direktno utiče na veličinu zrna. Kod
uzoraka sa 0.01 at% Ho, veličina zrna kretala se u opsegu
od 10 µm do 30 µm, dok je daljim povećanjem koncentracije
(0.1 at% Ho) ona opala na 5–20 μm. Najmanja veličina zrna
zabeležena je kod uzoraka sa 0.5 at% Ho (2–3 μm) i 1.0 at%
Ho (0.2–2 μm). Za sve uzorke specifična električna
otpornostnost merena je u temperaturnom intervalu od 30 °C
do 170 °C i u frekventnom opsegu od 100 Hz do 1 MHz. Porast
temperature doveo je do povećanja otpornosti. Od sobne
temperature do 100 °C taj porast je blaži, nakon čega sledi
nagli skok vrednosti. Nasuprot tome, povećanje frekvencije
dovodi do pada specifične otpornosti, sa posebno izraženim
padom iznad 200 kHz. Pored specifične električne
otpornosti, ispitivan je i temperaturni koeficijent
specifične električne otpornosti (α). Kod svih ispitanih
uzoraka potvrđen je PTC efekat (pozitivni temperaturni
koeficijent otpornosti) u temperaturnom opsegu od 30 °C do
128 °C.