ChemInform Abstract: Plasmonic Cu_2‐xS Nanocrystals: Optical and Structural Properties of Copper‐Deficient Copper(I) Sulfides.

Abstract

Copper I 7400 Plasmonic Cu2-xS Nanocrystals: Optical and Structural Properties of Copper--Deficient Copper(I) Sulfides. -Cu 2-x S (x = 1, 0.2, 0.03) nanocrystals are prepared by three different convenient and environmental benign techniques based on sonoelectrochemical, hydrothermal, and solventless thermolysis methods using CuSO4 as starting material. The samples are characterized by powder XRD, TEM, UV/VIS, and NIR spectroscopy. The compositions of the nanocrystals ranges from CuS to Cu1.97S by adjusting the reduction potential in the sonoelectrochemical method, from CuS to Cu 1.97 S by adjusting the pH values in the hydrothermal method, and from Cu1.8S to Cu1.97S in the thermolysis method. Cu2S is thermodynamically unstable under ambient conditions, compared to the Cu2-xS phase. All Cu2-xS nanocrystals show a blue shift in the band gap absorption compared to bulk Cu2-xS and are of direct band gap type, different from previously reported experimental results. Cu 2-x S nanocrystals show a plasmonic absorption, which depends on the carrier concentration. -(ZHAO, Y.; PAN, H.; LOU, Y.; QIU, X.; ZHU*, J.; BURDA, C.; J.

Active Manipulation of NIR Plasmonics: the Case of Cu2–xSe through Electrochemistry

“…12,13 The discovery of doped semiconductors supporting localized surface plasmon resonance (LSPR), a property traditionally linked to noble metal NPs, opens up a door for active plasmonics. Their intrinsic resonances lie in the NIR region 14,15 and display larger optical modulation depth as a result of low carrier density (10 16 to 10 22 cm −3 ), 16,17 demonstrated previously through chemical redox reactions. 18−20 More quantitative and dynamic electrochemical tuning of plasmonics is still limited to metal oxide NPs through capacitive charging effect, 21 which has little effect on their electronic structures.…”

Recent Advances in Combination of Copper Chalcogenide-Based Photothermal and Reactive Oxygen Species-Related Therapies

“…Ascribed to the strong localized surface plasmon resonance (LSPR) arising from copper defects, where the abundant free carriers of Cu 2−x E significantly interact with the oscillating electromagnetic field of driving light, Cu range of both NIR-I (750−900 nm) and NIR-II (1000−1700 nm) biological windows. 19,20 In addition, the vital trace elements copper and chalcogen released from Cu 2−x E could contribute to human health. 21 Moreover, Cu 2−x E is simple to synthesize and easy to functionalize, rendering it a hopeful PTA for PTT application.…”

Effect of Surface Ligand on Chemical Interface Damping in Nonstoichiometric Cu2–xS Semiconductor Nanocrystals: A Direct Correlation between Ultrafast Carrier Dynamics and Photoconductivity

“…where the effective mass of the hole is approximately 0.8m 0 , 26 and m 0 is the rest mass of an electron. Free carrier concentrations are estimated from Drude's equation, and it is found to be approximately 4.8 × 10 21 cm −3 and 4.2 × 10 21 cm −3 for Cu OLM and Cu OA NCs, respectively.…”

“…Red shifting of plasmonic band followed by increment of bandwidth of plasmonic semiconductor is due to decrement of carrier (hole) concentrations and can be attributed to stronger CID effect. 29,30 The shifting of LSPR and CID are two distinct phenomena. Shifting of LSPR happens with changing carrier concentration (n h ), whereas CID refers to carrier delocalization between NCs and surface adsorbate interfacial system.…”

“…25,31 Among different relaxation processes hole−hole scattering (τ h-h ) is very important, which creates a thermal distribution of hot holes, and the typical scattering time lies in a few hundreds of femtoseconds (fs). 32 Later on, thermally distributed hot holes are thermalized via hole−phonon (∼few picoseconds) and phonon−phonon (∼few hundreds of picoseconds) scattering processes. 4,15 In addition to the above-mentioned plasmon relaxation processes, there is another type of decay channel that exists in the presence of molecular adsorbates, namely, a decay due to chemical interface damping (CID).…”