Advanced Photonics Research最新文献

Lead halide perovskite nanocrystals (PNCs) are a highly promising class of materials for optoelectronic applications, due to their exceptional optical properties. Nevertheless, their poor stability has remained a major obstacle to practical implementation. This work reports highly stable lead halide PNCs of the compositions MAPbBr₃ and FAPbBr₃ (MA = methylammonium, FA = formamidinium). The nanocrystals are prepared via a facile, single-step precipitation procedure using the amino acid derivative N_α-(tert-butoxycarbonyl)-L-lysine (boc-Lys) and hexanoic acid as ligands. Films of the precipitated nanocrystals exhibit near-unity photoluminescence quantum yields and outstanding stability, maintaining their optical properties for more than 150 days (MAPbBr₃) and 490 days (FAPbBr₃) under ambient conditions, and for over 20 h under continuous blue light excitation. The excellent stability of the nanocrystals is attributed to an in situ formed encapsulating matrix, which initially consists of a complex formed between PbBr₂ and boc-Lys. Furthermore, it is demonstrated that the isolated PbBr₂/boc-Lys matrix material can be used as precursor for growing highly luminescent, stable MAPbBr₃ nanocrystals through exposure to methylammonium bromide vapors. The presented nanocrystals are excellent candidates for light-emission applications and could provide a blueprint for designing precursor materials for the growth of high-quality, stable PNCs via metal halide-amino acid complexes.

The photoinitiating system (PIS) is a key component of holographic materials which needs to be carefully selected and optimized to achieve efficient photopolymerization and, as a result, highly efficient holographic structures. Recently, boron dipyrromethene (BODIPY) dyes have been introduced as a new class of photosensitizers for holographic materials, including photopolymerizable glass, which is characterized by excellent environmental stability. Here, we present a study of the holographic recording capability of a photopolymerizable glass, where PIS was optimized using two approaches: (1) adding a second co-initiator, diphenyl iodonium hexafluorophosphate (DPIHFP) and (2) exploring a range of BODIPY structures, such as anthracene- and pyrene-BODIPYs. The performance of a novel pyrene-BODIPY dyad was compared with commercially available Erythrosine B, used as a reference. Remarkably, a 9-fold increase in the diffraction efficiency and refractive index modulation (RIM) was achieved by replacing Erythrosine B with pyrene-BODIPY dyads, indicating enhanced photopolymerization kinetics with BODIPY sensitization. In addition, incorporating a second co-initiator, DPIHFP, further increases the exposure sensitivity by a factor of three. These results demonstrate the high efficiency of BODIPY-based PIS formulations and underscore photopolymerizable glass as a promising platform for developing highly efficient holographic optical elements.

The photoinitiating system (PIS) is a key component of holographic materials which needs to be carefully selected and optimized to achieve efficient photopolymerization and, as a result, highly efficient holographic structures. Recently, boron dipyrromethene (BODIPY) dyes have been introduced as a new class of photosensitizers for holographic materials, including photopolymerizable glass, which is characterized by excellent environmental stability. Here, we present a study of the holographic recording capability of a photopolymerizable glass, where PIS was optimized using two approaches: (1) adding a second co-initiator, diphenyl iodonium hexafluorophosphate (DPIHFP) and (2) exploring a range of BODIPY structures, such as anthracene- and pyrene-BODIPYs. The performance of a novel pyrene-BODIPY dyad was compared with commercially available Erythrosine B, used as a reference. Remarkably, a 9-fold increase in the diffraction efficiency and refractive index modulation (RIM) was achieved by replacing Erythrosine B with pyrene-BODIPY dyads, indicating enhanced photopolymerization kinetics with BODIPY sensitization. In addition, incorporating a second co-initiator, DPIHFP, further increases the exposure sensitivity by a factor of three. These results demonstrate the high efficiency of BODIPY-based PIS formulations and underscore photopolymerizable glass as a promising platform for developing highly efficient holographic optical elements.

Lead halide perovskite nanocrystals (PNCs) are a highly promising class of materials for optoelectronic applications, due to their exceptional optical properties. Nevertheless, their poor stability has remained a major obstacle to practical implementation. This work reports highly stable lead halide PNCs of the compositions MAPbBr₃ and FAPbBr₃ (MA = methylammonium, FA = formamidinium). The nanocrystals are prepared via a facile, single-step precipitation procedure using the amino acid derivative N_α-(tert-butoxycarbonyl)-L-lysine (boc-Lys) and hexanoic acid as ligands. Films of the precipitated nanocrystals exhibit near-unity photoluminescence quantum yields and outstanding stability, maintaining their optical properties for more than 150 days (MAPbBr₃) and 490 days (FAPbBr₃) under ambient conditions, and for over 20 h under continuous blue light excitation. The excellent stability of the nanocrystals is attributed to an in situ formed encapsulating matrix, which initially consists of a complex formed between PbBr₂ and boc-Lys. Furthermore, it is demonstrated that the isolated PbBr₂/boc-Lys matrix material can be used as precursor for growing highly luminescent, stable MAPbBr₃ nanocrystals through exposure to methylammonium bromide vapors. The presented nanocrystals are excellent candidates for light-emission applications and could provide a blueprint for designing precursor materials for the growth of high-quality, stable PNCs via metal halide-amino acid complexes.

Current diagnostic tools for multidrug-resistant tuberculosis (MDR-TB) are molecular assay-based and have challenges associated with labor-intensive workflows, complex laboratory infrastructures, and limited mutation coverage. This highlights the need for alternative techniques that can be used as diagnostic tools for MDR-TB. In this study, we demonstrated the use of an surface plasmon resonance (SPR)-based biosensor chip for the detection of selected genes (InhA, KatG, and RpoB) within the MDR-TB genome using single-stranded deoxyribonucleic acids (ssDNA) targets and thiolated probes. The probes were successfully functionalized to AuNPs and confirmed using UV–vis and DLS. On SPR-based detection, the hybridization of the selected probes to complementary and non-complementary targets induced changes in the resonance angles. The hybridization of the selected probes to the targets was observed at resonance angles of 46.85, 46.77, 45.84, and 46.91° for the IS6110, InhA, KatG, and RpoB genes, respectively. In contrast, the unhybridized probe and the non-complementary targets exhibited resonance angles of 46.33, 46.05, 45.53, and 45.85° for the IS6110, InhA, KatG, and RpoB genes, respectively. The data showed that SPR-based biosensing can be refined and considered as an alternative approach to detect and differentiate between different ssDNA targets using thiolated probes as biorecognition elements for MDR-TB detection.

Current diagnostic tools for multidrug-resistant tuberculosis (MDR-TB) are molecular assay-based and have challenges associated with labor-intensive workflows, complex laboratory infrastructures, and limited mutation coverage. This highlights the need for alternative techniques that can be used as diagnostic tools for MDR-TB. In this study, we demonstrated the use of an surface plasmon resonance (SPR)-based biosensor chip for the detection of selected genes (InhA, KatG, and RpoB) within the MDR-TB genome using single-stranded deoxyribonucleic acids (ssDNA) targets and thiolated probes. The probes were successfully functionalized to AuNPs and confirmed using UV–vis and DLS. On SPR-based detection, the hybridization of the selected probes to complementary and non-complementary targets induced changes in the resonance angles. The hybridization of the selected probes to the targets was observed at resonance angles of 46.85, 46.77, 45.84, and 46.91° for the IS6110, InhA, KatG, and RpoB genes, respectively. In contrast, the unhybridized probe and the non-complementary targets exhibited resonance angles of 46.33, 46.05, 45.53, and 45.85° for the IS6110, InhA, KatG, and RpoB genes, respectively. The data showed that SPR-based biosensing can be refined and considered as an alternative approach to detect and differentiate between different ssDNA targets using thiolated probes as biorecognition elements for MDR-TB detection.

GeSn has emerged as a promising alternative in Si photonics due to its narrow and tunable bandgap. In this study, GeSn waveguide photodetectors (WGPDs) based on a lateral p–i–n homojunction architecture are demonstrated. Incorporating 10.82% Sn effectively reduces the bandgap, extending the photodetection range to 2745 nm and covering the entire short-wave infrared (SWIR) region. A lateral p–i–n homojunction diode with good optical confinement and long photon-absorbing length is developed to significantly enhance the optical responsivity. The close proximity of the direct (Γ_c) and indirect (L_c) conduction bands allows excitation of electrons from Γ_c to L_c, increasing electron lifetime. As a result, the carrier collection efficiency improves with higher bias. This momentum-space separation mechanism enables device operation at a low electric field of ≈2.5 kV cm⁻¹. These findings suggest that the fabricated GeSn WGPDs are strong candidates for full-range SWIR detection applications.

GeSn has emerged as a promising alternative in Si photonics due to its narrow and tunable bandgap. In this study, GeSn waveguide photodetectors (WGPDs) based on a lateral p–i–n homojunction architecture are demonstrated. Incorporating 10.82% Sn effectively reduces the bandgap, extending the photodetection range to 2745 nm and covering the entire short-wave infrared (SWIR) region. A lateral p–i–n homojunction diode with good optical confinement and long photon-absorbing length is developed to significantly enhance the optical responsivity. The close proximity of the direct (Γ_c) and indirect (L_c) conduction bands allows excitation of electrons from Γ_c to L_c, increasing electron lifetime. As a result, the carrier collection efficiency improves with higher bias. This momentum-space separation mechanism enables device operation at a low electric field of ≈2.5 kV cm⁻¹. These findings suggest that the fabricated GeSn WGPDs are strong candidates for full-range SWIR detection applications.

Quasi-2D metal-halide perovskite LEDs (PeLEDs) are promising for displays but remain limited by trap-mediated loss and short lifetimes, especially in the blue. Here, we report a triple-cation A-site doping strategy by co-incorporating Rb⁺ and guanidinium (GA⁺) with Cs⁺ to simultaneously improve efficiency and stability. Rb⁺ contracts the lattice and extends the radiative lifetime, whereas GA⁺ predominantly passivates surface and interfacial defects and moderates the quasi-2D phase distribution. Together they extend photoluminescence lifetimes and suppress trap-assisted nonradiative pathways, as confirmed by time-resolved photoluminescence and trap analyses. We further augment the device performance by a yttrium additive and a modified hole-injection layer. The optimized sky-blue devices achieve an external quantum efficiency of 9.0% at 492 nm and the operating lifetime (T₅₀) over 18 min at 100 cd m⁻². This synergy between A-site alloying, additive engineering, and HTL modification provides a practical route toward efficient, more stable sky-blue quasi-2D PeLEDs.

Quasi-2D metal-halide perovskite LEDs (PeLEDs) are promising for displays but remain limited by trap-mediated loss and short lifetimes, especially in the blue. Here, we report a triple-cation A-site doping strategy by co-incorporating Rb⁺ and guanidinium (GA⁺) with Cs⁺ to simultaneously improve efficiency and stability. Rb⁺ contracts the lattice and extends the radiative lifetime, whereas GA⁺ predominantly passivates surface and interfacial defects and moderates the quasi-2D phase distribution. Together they extend photoluminescence lifetimes and suppress trap-assisted nonradiative pathways, as confirmed by time-resolved photoluminescence and trap analyses. We further augment the device performance by a yttrium additive and a modified hole-injection layer. The optimized sky-blue devices achieve an external quantum efficiency of 9.0% at 492 nm and the operating lifetime (T₅₀) over 18 min at 100 cd m⁻². This synergy between A-site alloying, additive engineering, and HTL modification provides a practical route toward efficient, more stable sky-blue quasi-2D PeLEDs.