Language：English   Publisher：Advanced Science  

This study demonstrates that optical absorption of the CsPbBr<inf>3</inf> quantum dots can be significantly enhanced through monolithic integration with the Tamm plasmon (TP) structure. This integration enables the resulting TP photodetector to achieve a higher photocurrent and a more linear power dependence compared to the reference device with a nonresonant configuration. The enhancement is confined to the designed resonant energy, while photons with off-resonance energies are fully reflected, making the TP photodetector an ideal candidate for compact and efficient image sensors, eliminating the need for additional filters or bulky microlenses for color discrimination or photon collection. Furthermore, the photocurrent generated by the TP photodetector can be regulated by varying light pulse stimulations, enabling it to mimic the synaptic dynamics of the human brain. By integrating the functions of perception, processing, and memorization of visual images, its potential for facial recognition through simulation based on a 64 × 64 array of TP photodetectors under the artificial neural network-based weight-update expectation thresholding model is demonstrated. These findings mark a significant step forward in utilizing all-inorganic perovskite materials for compact, color-filter-free image sensors and open new avenues for photonic neural computations on a single platform.

DOI： 10.1002/advs.202503464

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

本研究では、アルカンチオール修飾金ナノ粒子とCdS量子ドットを交互に積層することで、異種ナノ粒子からなる人工的な三次元多層構造を作製し、その発光特性を制御した。申請者は主に光学特性の解析を担当し、有効媒質近似に基づく新しい計算手法を用いて、積層構造における偶数層・奇数層で異なる発光強度の増減挙動を再現した。さらに、金ナノ粒子のプラズモン応答と量子ドット発光の相互作用を解析することで、層数に依存した発光制御機構の解明に貢献した。

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nanoscale  

本研究では、ペロブスカイトナノ粒子の自己組織化単粒子膜を自在に積層・パターン形成することを可能にする、ポリジメチルシロキサン（PDMS）膜を用いた膜転写手法を提案した。
具体的には、転写元および転写先基板の表面エネルギーをシランカップリングにより制御することで、ナノ粒子への追加処理を行うことなく、効率的な膜転写が可能であることを実証した。本成果は、様々なナノ光デバイスへの応用展開に資するものである。

DOI： 10.1039/D4NR05088F

Web of Science

Scopus

PubMed

Publishing type：Research paper (international conference proceedings)   Publisher：Proceedings of SPIE the International Society for Optical Engineering  

Semiconductor optical refrigeration utilizes the energy upconversion of light via anti-Stokes (AS) photoluminescence (PL), which occurs through a phonon-assisted optical absorption process. This process is advantageous for semiconductors with strong electron-phonon (e-ph) interactions, such as lead halide perovskites. We discuss the significance of short-range e-ph interactions in the AS-PL process, rather than the long-range Fröhlich interactions. Short-range e-ph interactions induce Urbach tail absorption, which is experimentally evaluated via the steepness parameter. We simulate the impact of the steepness parameter on the photo-cooling gain and efficiency. We also focus on halide perovskite CsPbBr3 quantum dots embedded in a Cs4PbBr6 host crystal, which possess both near-unity PL quantum efficiency and strong e-ph interactions, and quantitatively evaluate their AS-PL properties. Based on the spectroscopic results, we discuss the possibility of semiconductor optical refrigeration using halide perovskite quantum dots.

DOI： 10.1117/12.2655039

Scopus

Publishing type：Research paper (scientific journal)   Publisher：American Physical Society ({APS})  

Lead halide perovskites possess high photoluminescence (PL) efficiency and strong electron-phonon interactions, and therefore optical cooling using up-conversion PL has been expected. We investigate anti-Stokes PL from green-luminescent Cs4PbBr6, whose origin is attributable to CsPbBr3 nanostructures embedded in a Cs4PbBr6 crystal. Because of the high transparency, low refractive index, and high stability of Cs4PbBr6, the green PL displays high external quantum efficiency without photodegradation. Time-resolved PL spectroscopy reveals the excitonic behaviors in the recombination process. The shape of the PL spectrum is almost independent of excitation photon energy, which means that the spectral width is determined by homogeneous broadening. We demonstrate that the phonon-assisted process dominates the Urbach tail of optical absorption and anti-Stokes PL at room temperature. Anti-Stokes PL is observed down to 70 K. We determine the temperature dependence of the Urbach energy and estimate the strength of the electron-phonon coupling. Our spectroscopic data show that CsPbBr3 nanostructures have potentially useful features for optical cooling.

DOI： 10.1103/PhysRevMaterials.6.L043001

Scopus

Event date： 2026.3

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：オンライン   Country：Japan  

Event date： 2025.9

Language：English   Presentation type：Poster presentation  

Venue：Kyushu University, ITO campus Inamori Hall   Country：Japan  

Event date： 2025.9

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Kyushu University, ITO campus Inamori Hall   Country：Japan  

Event date： 2025.9

Language：English   Presentation type：Poster presentation  

Venue：Kyushu University, ITO campus Inamori Hall   Country：Japan  

Event date： 2025.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名城大学　天白キャンパス  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (other)