GaN nanowire (NW)-based hybrid structures have attracted attention for optoelectronic applications due to their high surface area and efficient carrier transport. However, the optical transparency of GaN NWs is often limited by unintended residual species accumulated on the surface and in the inter-wire regions, as well as defect-related absorption, leading to reduced light transmission. In this work, we demonstrate that thermal annealing significantly improves the optical transparency of GaN NWs grown on indium tin oxide (ITO)/glass substrates. The transmittance increased from 47.9% to 78.5% at 550 nm after rapid thermal annealing at 800^oC for 3 min, while a comparable value (~75.5%) was achieved at 600^oC for 5 min. PbBr₃ was deposited onto the GaN NWs to form hybrid structures, and temperature-dependent photoluminescence (TDPL) measurements revealed enhanced emission stability with suppressed peak shift and reduced spectral broadening. Arrhenius analysis based on a two-channel model revealed that the activation energy of the dominant non-radiative recombination pathway increased from 62 meV in the as-grown sample to 85 meV after thermal annealing, while its relative contribution remained nearly unchanged. In contrast, the shallow trap-assisted pathway exhibited a similar activation energy of approximately 6 meV in both samples, but its contribution decreased from 0.35 to 0.17 after annealing. As a result, the internal quantum efficiency (IQE) improved from 75.9% to 87.4%. These results show that thermal annealing improves optical transparency by removing residuals and suppresses defect-related recombination, leading to enhanced carrier dynamics and improved optical performance of PbBr₃-based hybrid structures.

Solution-processed organic light-emitting diodes (OLEDs) have the advantages of low cost, fast fabrication, and large-area devices. However, most studies on solution-processed OLEDs have mainly focused on solution-processable hole transporting materials or emissive materials. Here, we report fully solution-processed green OLEDs including hole/electron transport layers and emissive layers. The electrical and optical properties of OLEDs based on solution-processed TPBi (2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) as the electron transport layer were investigated with respect to the spin speed and the number of layers. The performance of OLEDs with solution-processed TPBi exhibits a power efficiency of 9.4 lm/W. We believe that the solution-processed electron transport layers can contribute to the development of efficient fully solution-processed multilayered OLEDs.

We have fabricated white organic light-emitting diodes (OLEDs) using several thicknesses ofelectron-transport layer. The multi-emission layer structure doped with red and blue phosphorescent guestemitters was used for achieving white emission. 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) wasused as an electron-transport layer. The thickness of BCP layer was varied to be 20, 55, and 120 nm. The current efficiency, emission and recombination characteristics of multi-layer white OLEDs wereinvestigated. The BCP layer thickness variation results in the shift of emission spectrum due to therecombination zone shift. As the BCP layer thickness increases, the recombination zone shifts toward theelectron-transport layer/emission-layer interface. The white OLED with a 55 nm thick BCP layerexhibited a maximum current efficiency of 40.9 cd/A.

In this Paper, we have developed1 a low temperature process to make two type of Paste by using TIO2 nanoprticles(P25). The interconnections between substrate and TiO2 films or link between particles of free-binder Paste (FP1, FPZ, FP3) is very poor. Therefore, the Titanium(IV) isopropoxide was added to the TP paste to improve the interconnection. Electron transport time (Tt) and recombination time (Tr) are analyzed by IMPS (intensity-modulated photocurrent spectroscopy) and INIVS (Intensity-modulated photovltage spectroscopy). In the results, Tt of TP paste based DSSCs (about 4.3×10-3) is faster than other samples. Tt is Ionger from 2.7×10-2 s of FP2 to 3.0×10-2 s of TP. A solar conversion efficiency (DSSCs) of TP 15 3.54% for an incident solar energy of 100 mw cm-2(meanwhile, 2. 70% for DSSCs With FP2). The c아1versioIl efficiency is increased by 1.3 times.

Dye-sensitized solar cells (DSSCs) based on titanium dioxide (TiO2) have been extensively studied because of their promising low-cost alternatives to conventional semiconductor based solar cells. DSSCs consist of molecular dye at the interface between a liquid electrolyte and a mesoporous wide-bandgap semiconductor oxide. Most efforts for high conversion efficiencies have focused on dye and liquid electrolytes. However, interface engineering between dye and electrode is also important to reduce recombination and improve efficiency. In this work, for interface engineering, we deposited semiconducting ferroelectric BiFeO3 with bandgap of 2.8 eV on TiO2 nanoparticles and nanotubes. Photovoltaic properties of DSSCs were characterized as a function of thickness of BiFeO3. We showed that ferroelectric BiFeO3-coated TiO2 electrodes enable to increase overall efficiency of DSSCs, which was associated with efficient electron transport due to internal electric field originating from electric polarization. It was suggested that engineering the dye-TiO2 interface using ferroelectric materials as inorganic modifiers can be key parameter for enhanced photovoltaic performance of the cell.