Two-Dimensional Group-10 Noble-Transition-Metal Dichalcogenides Photodetector

2D Transition-Metal Dichalcogenides (TMDs) have been widely considered as a promising material for future optoelectronics due to the strong light-matter interaction, fantastic electronic properties and environmental stability. However, the relatively large bandgap and low mobility of conventional TMDs (such as MoS2 and WS2) limit their applications in infra optoelectronics and high-speed photodetection. In this chapter, we introduce a new type of group-10 noble TMDs (NTMDs), which exhibit outstanding properties such as unique structural phase, widely tunable energy gap and high mobility. Till now, various NTMDs-based photodetectors have been realized with ultrabroad detection waveband (200 nm to 10.6 μm), fast response time, high responsivity and detectivity, and polarization sensitivity. NTMDs have been excellent potential candidates for next-generation photodetection devices with high-performance, wafer-scalability and flexibility

Effect of impurities on the Raman scattering of 6H-SiC crystals

Raman spectroscopy was applied to different-impurities-doped 6H-SiC crystals. It had been found that the first-order Raman spectra of N-, Al- and B-doped 6H-SiC were shifted to higher frequency when comparing with undoped samples. However, the first-order Raman spectra of V-doped sample was shifted to lower frequency, revealing that there existed low free carrier concentration, which might be induced by the deep energy level effect of V impurity. Meanwhile, the second-order Raman spectra are independent of polytype and impurity type

Probing the waveguiding properties of quasi-2D organic semiconductor through optical imaging

Though there have been many investigations focusing on organic semiconductors, how to fully probe their waveguiding properties is still rarely reported. In this work, the light propagation loss in the Znq _2 samples was detected by a modified light transmission path. The results showed that the optical propagation loss coefficient of Znq _2 nanorods is ∼0.16 dB μ m ^−1 . Our work fully reveals the waveguiding properties in 2D organic semiconductor by 2D & 3D imaging, which may offer a new reference for exploring novel optical properties of 2D organic semiconductors

Photonics and Optoelectronics of Low-Dimensional Materials

201812 bcrcVersion of RecordPublishe

Modulation of the optical bandgap and photoluminescence quantum yield in pnictogen (Sb3+/Bi3+)-doped organic-inorganic tin(IV) perovskite single crystals and nanocrystals

Water-stable, lead-free zero-dimensional (0D) organic-inorganic hybrid colloidal tin(IV) perovskite, A(2)SnX(6) (A is a monocationic organic ion and X is a halide) nanocrystals (NCs) with high photoluminescence (PL) quantum yield (QY) have rarely been explored. Herein, we report solution-processed colloidal NCs of blue light-emitting T2SnCl6 and orange light-emitting T2Sn1-xSbxCl6 [T+ = tetramethylammonium cation] from their corresponding single crystals (SCs). These colloidal NCs are well-dispersible in nonpolar solvents, thereby maintaining their bright emission. This paves the way for fabricating homogeneous thin films of these NCs. Due to organic cation (T+)-controlled large spin-orbit coupling (SOC), the T2Sn1-xSbxCl6 NCs exhibit bright orange emission with an enhancement in PL QY of 41% compared to their bulk counterpart. Furthermore, we explore T2Sn1-xBixCl6 and T2Sn1-x-yBixSbyCl6 SCs, which show blue and green emission, respectively; the latter is attributed to the newly formed Sb 5p and Sb 5 s orbital-driven band structures confirmed by applying density functional theory (DFT) calculations. The SCs and NCs exhibit excellent stability in water under ambient conditions because of the in-situ generation of a hydrophobic and oxygen-resistant passivating layer of oxychloride in the presence of water. Our findings open a pathway for designing lead-free perovskites materials for thin-film-based optoelectronic devices. (C) 2021 Elsevier Inc. All rights reserved

Boosting the efficiency of quantum dot–sensitized solar cells over 15% through light‐harvesting enhancement

Abstract How to improve the capacity of light‐harvesting is still an important point and essential strategy for the assembling of high‐efficiency quantum dot–sensitized solar cells (QDSCs). A believable approach is to implant new light absorption materials into QDSCs to stimulate the charge transfer. Herein, the few‐layer black phosphorus quantum dots (BPQDs) are synthesized by electrochemical intercalation technology using bulk BP as source. Then the obtained BPQDs are deposited onto the surface of Zn–Cu–In–S–Se (ZCISSe) QD‐sensitized TiO2 substrate to serve as another light‐harvesting material for the first time. The experimental results have shown that BPQDs can not only increase the absorption intensity by photoanode but also reduce unnecessary charge recombination processes at the interface of photoanode/electrolyte. Through optimizing the size and deposition process of BPQDs, the champion power conversion efficiency of ZCISSe QDSCs is increased to 15.66% (26.88 mA/cm2, Voc = 0.816 V, fill factor [FF] = 0.714) when compared with the original value of 14.11% (Jsc = 25.41 mA/cm2, Voc = 0.779 V, FF = 0.713)