facet-to-facet-linking-shape-anisotropic-colloidal-cadmium

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

National University of Singapore

Multifunctional peptide-polymer hybrid materials have been applied as efficient and biocompatible quantum-dot coating materials. Significant pH responsiveness (e.g., an influence of the pH on the quantum yields of the peptide-polymer/QDs) was found and is attributed to conformational rearrangements of the peptide backbone.

pH-Responsive quantum dots via an albumin polymer surface coating.

Sowing the seeds: the growth of Au and Ag(2)S nanoparticles at distinct positions on CdSe-seeded CdS heterostructured nanorods can be precisely controlled by variations in the concentration of the Au and Ag precursors, respectively. The ability to direct growth on the nanorods can lead to "Janus-type" structures where Au is located at the more reactive end of the nanorod, whilst Ag(2)S is located at the other (see picture; CdSe dark blue, CdS light blue, Au yellow, Ag(2)S gray).

Asymmetric dumbbells from selective deposition of metals on seeded semiconductor nanorods.

Engineering fluorescence in Au-tipped, CdSe-seeded CdS nanoheterostructures.

&#x8D85;&#x4F4E;&#x95E8;&#x69DB;&#x53CC;&#x5149;&#x5B50;&#x62BD;&#x6C34;&#x653E;&#x5927;&#x81EA;&#x53D1;&#x8F90;&#x5C04; &#xFF08;2ASE&#xFF09;&#xFF0C;&#x7B2C;&#x4E00;&#x6B21;&#x76F4;&#x64AD; CdSe/CdS &#x7EB3;&#x7C73;/&#x7EB3;&#x7C73;&#x5F02;&#x8D28;&#x7ED3;&#x6784;&#x4E2D;&#x6FC0;&#x5C04;&#x8868;&#x660E;&#x4E86;&#x3002;&#x8FD9;&#x79CD;&#x5F02;&#x8D28;&#x7ED3;&#x6784;&#x5141;&#x8BB8;&#x72EC;&#x7ACB;&#x8C03;&#x8C10;&#x7684;&#x53CC;&#x5149;&#x5B50;&#x5438;&#x6536; (2PA) &#x622A;&#x9762; (&sigma;(2)) &#x901A;&#x8FC7; Cd &#x6746;&#x5927;&#x5C0F;&#xFF0C;&#x548C;&#x901A;&#x8FC7;&#x4E0D;&#x540C; CdSe &#x70B9;&#x5927;&#x5C0F;&#x7684;&#x53D1;&#x5C04;&#x6CE2;&#x957F;&#x7684;&#x53D8;&#x5316;&#x3002;&#x4E0E;&#x589E;&#x5F3A;&#x7684; &sigma;(2)&#xFF0C;2ASE &#x8FD9;&#x4E9B;&#x5F02;&#x8D28;&#x7ED3;&#x6784;&#x88AB;&#x5B9E;&#x73B0;&#x8D85;&#x4F4E;&#x95E8;&#x69DB;&#x6CE8;&#x91CF;&#x7684; &sim;1.5 mJ/cm(2)&#xFF0C;&#x8FD9;&#x662F;&#x9AD8;&#x8FBE;&#x4E00;&#x4E2A;&#x8BA2;&#x5355;&#x4F4E;&#x4E8E;&#x6240;&#x9700;&#x7684;&#x7403;&#x5F62;&#x534A;&#x5BFC;&#x4F53; NCs&#x3002; &#x91CD;&#x8981;&#x7684;&#x662F;&#xFF0C;&#x901A;&#x8FC7;&#x5229;&#x7528;&#x8FD9;&#x552F;&#x4E00;&#x53C2;&#x5C55;&#x5373;&#x4F7F;&#x5728;&#x76F8;&#x5BF9;&#x8F83;&#x5927;&#x6746;&#x5F3A;&#x91CF;&#x5B50;&#x53D7;&#x9650;&#x7684;&#x76F4;&#x64AD;&#x7EB3;&#x7C73;&#x68D2;&#x7684;&#x5C5E;&#x6027;&#x5927;&#x5C0F;&#x4E0D;&#x4E00;&#xFF0C;2ASE &#x9608;&#x503C;&#x4E0E; 2PA &#x884C;&#x52A8;&#x622A;&#x9762; &#xFF08;&sigma;(2)&eta;) &#xFF08;&#x5176;&#x4E2D; &eta; &#x662F;&#x91CF;&#x5B50;&#x4EA7;&#x91CF;&#xFF09; &#x88AB;&#x53D1;&#x73B0;&#x8FD1;&#x4E92;&#x60E0;&#x5173;&#x7CFB;&#x548C;&#x5BA1;&#x5B9A;&#x4E3A;&#x7B2C;&#x4E8C;&#x81F3;&#x7B2C;&#x516D;&#x534A;&#x5BFC;&#x4F53;&#x7EB3;&#x7C73;&#x7ED3;&#x6784;&#x7684;&#x5BBD;&#x91CF;&#x8303;&#x56F4;&#x5185;&#x3002;&#x8D85;&#x5FEB;&#x5149;&#x5B66;&#x5149;&#x8C31;&#x5DF2;&#x9A8C;&#x8BC1;&#x867D;&#x7136;&#x8FD9;&#x4E9B;&#x5F02;&#x8D28;&#x7ED3;&#x6784;&#x7684;&#x87BA;&#x65CB;&#x8FC7;&#x7A0B;&#x7684;&#x786E;&#x88AB;&#x9690;&#x542B;&#xFF0C;ASE &#x8FD9;&#x4E9B;&#x6837;&#x54C1;&#x4E2D;&#x7684;&#x4E5F;&#x4F1A;&#x5F3A;&#x70C8;&#x5F71;&#x54CD;&#x7531;&#x4E8C; &#x25CB; &#x25CB; &#x4E09;&#x9762;&#x5404;&#x56FD;&#x5FEB;&#x901F;&#x5B54;&#x9677;&#x5370;&#x8FDB;&#x7A0B;&#x3002;&#x6700;&#x540E;&#xFF0C;&#x4EE5;&#x4F5C;&#x4E3A;&#x5B9E;&#x73B0;&#x53CC;&#x5149;&#x5B50;&#x6FC0;&#x5149;&#x7684;&#x53EF;&#x884C;&#x589E;&#x76CA;&#x4ECB;&#x8D28;&#x4E2D;&#x4F53;&#x73B0;&#x8FD9;&#x4E9B;&#x79CD;&#x5B50; CdSe/CdS &#x7EB3;&#x7C73;/&#x7EB3;&#x7C73;&#x5F02;&#x8D28;&#x7ED3;&#x6784;&#x7684;&#x6F5C;&#x529B;&#xFF0C;&#x88AB;&#x5C55;&#x793A;&#x9AD8;&#x5EA6; photostable &#x5FAE;&#x7403;&#x6FC0;&#x5149;&#x4E0E;&#x8D85;&#x4F4E;&#x6CF5;&#x9608;&#x503C;&#x3002;

&#x8D85;&#x4F4E;&#x95E8;&#x69DB;&#x53CC;&#x5149;&#x5B50;&#x62BD;&#x6C34;&#x653E;&#x5927;&#x81EA;&#x53D1;&#x8F90;&#x5C04;&#x548C;&#x6FC0;&#x5149;&#x4ECE;&#x76F4;&#x64AD;&#x7684; CdSe/CdS &#x7EB3;&#x7C73;&#x5F02;&#x8D28;&#x7ED3;&#x6784;&#x3002;

Ultralow-threshold two-photon pumped amplified spontaneous emission (2ASE) and lasing in seeded CdSe/CdS nanodot/nanorod heterostructures is demonstrated for the first time. Such heterostructures allow the independent tunability of the two-photon absorption (2PA) cross-section (Ïƒ(2)) through varying the CdS rod size, and that of the emission wavelength through varying the CdSe dot size. With an enhanced Ïƒ(2), 2ASE in these heterostructures is achieved with an ultralow threshold fluence of âˆ¼1.5 mJ/cm(2), which is as much as one order less than that required for spherical semiconductor NCs. Importantly, by exploiting this unique property of the seeded nanorods exhibiting strong quantum confinement even at relatively large rod sizes, a near reciprocal relation between the 2ASE threshold and the 2PA action cross-section (Ïƒ(2)Î·) (where Î· is the quantum yield) was found and validated over a wide volume range for II-VI semiconductor nanostructures. Ultrafast optical spectroscopy verified that while the Auger processes in these heterostructures are indeed suppressed, ASE in these samples could also be strongly affected by a fast hole-trapping process to the NR surface states. Lastly, to exemplify the potential of these seeded CdSe/CdS nanodot/nanorod heterostructures as a viable gain media for achieving two-photon lasing, a highly photostable microsphere laser with an ultralow pump threshold is showcased.

Ultralow-Threshold Two-Photon Pumped Amplified Spontaneous Emission and Lasing from Seeded CdSe/CdS Nanorod Heterostructures.

Ultralow-seuil biphotonique pomp&eacute; l&#39;&eacute;mission spontan&eacute;e amplifi&eacute;e (2ASE) et laser dans des h&eacute;t&eacute;rostructures &agrave; NANOPOINTS/nanotige CdSe/CdS ensemenc&eacute;es est d&eacute;montr&eacute; pour la premi&egrave;re fois. Ces h&eacute;t&eacute;rostructures permettent l&#39;accordabilit&eacute; ind&eacute;pendante de la section transversale de l&#39;absorption biphotonique (2PA) (&sigma;(2)) par le biais de varier la taille de tige de CdS et celle de la longueur d&#39;onde d&#39;&eacute;mission par le biais de varier la taille de point du CdSe. Avec une &sigma;(2) accrue, 2ASE dans ces h&eacute;t&eacute;rostructures est obtenue avec une fluence seuil ultra basse de &sim;1 mJ/cm(2), qui est autant un ordre inf&eacute;rieur &agrave; celui requis pour semi-conducteurs sph&eacute;rique NCs. ce qui est important, en exploitant cette propri&eacute;t&eacute; unique de la nanotiges ensemenc&eacute;s pr&eacute;sentant le confinement quantique solide m&ecirc;me &agrave; la tige de relativement grande tailles, une proche relation r&eacute;ciproque entre le seuil de 2ASE et la section d&#39;action 2PA (&sigma;(2)&eta;) (o&ugrave; &eta; est le rendement quantique) a &eacute;t&eacute; trouv&eacute; et valid&eacute;s sur une plage de large volume de nanostructures semi-conductrices II-VI. Spectroscopie optique ultrarapide v&eacute;rifi&eacute; que tandis que les processus Auger dans ces h&eacute;t&eacute;rostructures sont en effet supprim&eacute;s, ASE dans ces &eacute;chantillons pourrait &eacute;galement &ecirc;tre fortement affect&eacute;e par un processus rapide de trou-pi&eacute;geage d&#39;&Eacute;tats de surface NR. Enfin, pour illustrer le potentiel de ces graines h&eacute;t&eacute;rostructures &agrave; NANOPOINTS/nanotige de CdSe/CdS comme un m&eacute;dia de gain viable pour la r&eacute;alisation de deux photons laser, un hautement photostable microsphere laser avec un seuil de pompe ultra basse est mis en valeur.

Ultra basse-seuil biphotonique pomp&eacute; d&#39;&eacute;mission spontan&eacute;e amplifi&eacute;e et laser de h&eacute;t&eacute;rostructures ensemenc&eacute;s CdSe/CD nanotige.

Ultralow-Schwelle zwei-Photonen gepumpt verst&auml;rkte spontane Emission (2ASE) und Lasern in ges&auml;ten CdSe/CdS-Nanodot/Nanorod-Heterostrukturen zum ersten Mal gezeigt wird. Solche Heterostrukturen erm&ouml;glichen die unabh&auml;ngige Einstellbarkeit der zwei-Photonen-Absorption (2PA) Querschnitt (&sigma;(2)) durch unterschiedliche die CdS-Wicklergr&ouml;&szlig;e und der Emissionswellenl&auml;nge durch Variation der CdSe-Punktgr&ouml;&szlig;e. Mit einer Weise Schwellenwert Fluenz von &sim;1.5 mJ/cm(2), sind durch eine verbesserte &sigma;(2) 2ASE in diese Heterostrukturen erreicht, die ist mehr als eine Bestellung weniger als f&uuml;r sph&auml;rische Halbleiter NCs. vor allem durch die Nutzung dieser unique-Eigenschaft der ges&auml;ten mit starken Quanten Beengtheit selbst bei relativ gro&szlig;en Stab ausstellen Gr&ouml;&szlig;en, eine nahe wechselseitige Beziehung zwischen der 2ASE-Schwelle und der 2PA-Aktion-Querschnitt (&sigma;(2)&eta;) (&eta; ist die Quantenausbeute) wurde gefunden instand zu halten und &uuml;ber ein breites Band-Bereich f&uuml;r II-VI-Halbleiter-Nanostrukturen. Ultraschnelle optische Spektroskopie sichergestellt, dass w&auml;hrend der Auger-Prozesse in diesen Heterostrukturen tats&auml;chlich unterdr&uuml;ckt, ASE in diesen Beispielen auch stark von einem schnellen Loch-Trapping-Prozess in die Oberfl&auml;chen NR-Staaten betroffen sein k&ouml;nnten. Um das Potenzial dieser ges&auml;ten CdSe/CdS-Nanodot/Nanorod-Heterostrukturen als eine tragf&auml;hige Gewinn-Medien f&uuml;r die Verwirklichung der zwei-Photonen-Lasern zu veranschaulichen, ist schlie&szlig;lich ein sehr lichtbest&auml;ndig Microsphere Laser mit einer Schwelle Weise Pumpe pr&auml;sentiert.

Weise-Threshold zwei-Photonen gepumpt verst&auml;rkte spontane Emission und Lasern aus ges&auml;ten CdSe/CdS Nanorod Heterostrukturen.

Ultralow-soglia due-fotone pompato l&#39;emissione spontanea amplificata (2ASE) e lasing in seminato CdSe/CD nanodot/nanorod eterostrutture &egrave; dimostrato per la prima volta. Tali eterostrutture permettono la sintonizzabilit&agrave; indipendente della sezione trasversale di assorbimento del due-fotone (2PA) (&sigma;(2)) attraverso variando le dimensioni asta CD e che la lunghezza d&#39;onda di emissione attraverso variando la dimensione del puntino CdSe. Con una maggiore &sigma;(2), 2ASE in questi eterostrutture &egrave; raggiunto con una fluenza bassissimo soglia di &sim;1.5 mJ/cm(2), che &egrave; come un ordine inferiore a quello richiesto per semiconduttori sferico NCs. importante, sfruttando questa propriet&agrave; unica della nanobastoni seminato espositrici confinamento quantico forte anche all&#39;asta di relativamente grande dimensioni, un vicino rapporto reciproco tra la soglia di 2ASE e la sezione trasversale azione 2PA (&sigma;(2)&eta;) (dove &eta; &egrave; il rendimento quantico) &egrave; stato trovato e convalidato in un range ampio volume per nanostrutture di semiconduttori II-VI. Spettroscopia ottica ultraveloce verificato che mentre i processi della coclea in questi eterostrutture infatti vengono soppressi, ASE in questi esempi poteva anche essere fortemente influenzata da un veloce processo foro-trapping negli stati superficiali NR. Infine, per esemplificare il potenziale di queste teste di serie eterostrutture nanodot/nanorod CdSe/CD come una media di guadagno vitale per il conseguimento di due-fotone lasing, &egrave; presentato un altamente Fotostabili microsfere laser con una soglia di pompa bassissimo.

Soglia di bassissimo due-fotone pompato emissione spontanea amplificata e Lasing da eterostrutture Nanorod seminato CdSe/CD.

&#x8D85;&#x4F4E;&#x95BE;&#x5024; 2 &#x5149;&#x5B50;&#x52B1;&#x8D77;&#x5897;&#x5E45;&#x81EA;&#x7136;&#x653E;&#x51FA;&#x5149; (2ASE) &#x3068;&#x30B7;&#x30FC;&#x30C9; CdSe/Cd &#x30CA;&#x30CE;&#x30C9;&#x30C3;&#x30C8;/&#x30CA;&#x30CE;&#x30ED;&#x30C3;&#x30C9;&#x306E;&#x30D8;&#x30C6;&#x30ED;&#x69CB;&#x9020;&#x306B;&#x304A;&#x3051;&#x308B;&#x30EC;&#x30FC;&#x30B6;&#x30FC;&#x767A;&#x632F;&#x304C;&#x521D;&#x3081;&#x3066;&#x793A;&#x3055;&#x308C;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x3053;&#x306E;&#x3088;&#x3046;&#x306A;&#x30D8;&#x30C6;&#x30ED;&#x8A31;&#x53EF;&#x72EC;&#x7ACB;&#x53EF;&#x5909; 2 &#x5149;&#x5B50;&#x5438;&#x53CE; (2 pa &#x307E;&#x3067;) &#x65AD;&#x9762;&#x7A4D; (Cd &#x30ED;&#x30C3;&#x30C9; &#x30B5;&#x30A4;&#x30BA; CdSe &#x30C9;&#x30C3;&#x30C8; &#x30B5;&#x30A4;&#x30BA;&#x306E;&#x5909;&#x5316;&#x3092;&#x901A;&#x3058;&#x3066;&#x767A;&#x5149;&#x6CE2;&#x9577;&#x306E;&#x5909;&#x5316;&#x3092;&#x901A;&#x3058;&#x3066; &sigma;(2))&#x3002;&#x5F37;&#x5316;&#x3055;&#x308C;&#x305F; &sigma;(2) &#x3068; 2ASE &#x3053;&#x308C;&#x3089;&#x306E;&#x30D8;&#x30C6;&#x30ED;&#x69CB;&#x9020;&#x306B;&#x304A;&#x3051;&#x308B;&#x3001;&#x8D85;&#x4F4E;&#x95BE;&#x5024;&#x30D5;&#x30EB;&#x30A8;&#x30F3;&#x30B9;&#x7403;&#x72B6;&#x534A;&#x5C0E;&#x4F53; NCs&#x3002; &#x91CD;&#x8981;&#x306A;&#x306F;&#x3001;&#x6BD4;&#x8F03;&#x7684;&#x5927;&#x304D;&#x306A;&#x68D2;&#x3067;&#x3082;&#x5F37;&#x3044;&#x91CF;&#x5B50;&#x9589;&#x3058;&#x8FBC;&#x3081;&#x51FA;&#x5C55;&#x30B7;&#x30FC;&#x30C9; &#x30CA;&#x30CE;&#x30ED;&#x30C3;&#x30C9;&#x306E;&#x30E6;&#x30CB;&#x30FC;&#x30AF;&#x306A;&#x65BD;&#x8A2D;&#x3092;&#x5229;&#x7528;&#x3057;&#x3066;&#x5FC5;&#x8981;&#x306A;&#x3088;&#x308A;&#x5C11;&#x306A;&#x3044;&#x30B5;&#x30A4;&#x30BA;&#x3001;2ASE &#x306E;&#x3057;&#x304D;&#x3044;&#x5024;&#x3068; &#xFF08;&#xFF08;&eta; &#x91CF;&#x5B50;&#x53CE;&#x7387;&#x3067;&#x3059;&#xFF09; &sigma;(2)&eta;) &#x304C;&#x767A;&#x898B;&#x3055;&#x308C;&#x305F; 2 pa &#x307E;&#x3067;&#x30A2;&#x30AF;&#x30B7;&#x30E7;&#x30F3;&#x65AD;&#x9762;&#x306B;&#x304A;&#x3051;&#x308B;&#x8FD1;&#x3044;&#x76F8;&#x4E92;&#x95A2;&#x4FC2;&#x3068;&#x3057;&#x3066; 1 &#x3064;&#x306E;&#x9806;&#x5E8F;&#x3067;&#x306F; &sim;1.5 mJ/cm(2) &#x306E;&#x9054;&#x6210;&#x3067;&#x3059;&#x3002;&#x5E83;&#x3044;&#x30DC;&#x30EA;&#x30E5;&#x30FC;&#x30E0;&#x7BC4;&#x56F2; II-VI &#x534A;&#x5C0E;&#x4F53;&#x30CA;&#x30CE;&#x69CB;&#x9020;&#x306E;&#x691C;&#x8A3C;&#x3002;&#x8D85;&#x9AD8;&#x901F;&#x5149;&#x5206;&#x5149;&#x3053;&#x308C;&#x3089;&#x30D8;&#x30C6;&#x30ED;&#x69CB;&#x9020;&#x306B;&#x304A;&#x3051;&#x308B;&#x30AA;&#x30FC;&#x30B8;&#x30A7; &#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x306F;&#x78BA;&#x304B;&#x306B;&#x6291;&#x5236;&#x3055;&#x308C;&#x3066;&#x3044;&#x308B;&#x9593;&#x306F;&#x3001;&#x3053;&#x308C;&#x3089;&#x306E;&#x30B5;&#x30F3;&#x30D7;&#x30EB;&#x306B;&#x304A;&#x3051;&#x308B; ASE &#x3082;&#x5F37;&#x304F;&#x9AD8;&#x901F;&#x6B63;&#x5B54;&#x6355;&#x7372;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x306B; NR &#x306E;&#x8868;&#x9762;&#x72B6;&#x614B;&#x306B;&#x3088;&#x3063;&#x3066;&#x5F71;&#x97FF;&#x3055;&#x308C;&#x3066;&#x3044;&#x308B;&#x53EF;&#x80FD;&#x6027;&#x3092;&#x78BA;&#x8A8D;&#x3057;&#x307E;&#x3057;&#x305F;&#x3002;&#x6700;&#x5F8C;&#x306B;&#x3001;&#x4E8C;&#x5149;&#x5B50;&#x30EC;&#x30FC;&#x30B6;&#x30FC;&#x767A;&#x632F;&#x3092;&#x9054;&#x6210;&#x3059;&#x308B;&#x305F;&#x3081;&#x306B;&#x5B9F;&#x884C;&#x53EF;&#x80FD;&#x306A;&#x5229;&#x5F97;&#x30E1;&#x30C7;&#x30A3;&#x30A2;&#x3068;&#x3057;&#x3066;&#x3053;&#x308C;&#x3089;&#x30B7;&#x30FC;&#x30C9; CdSe/Cd &#x30CA;&#x30CE;&#x30C9;&#x30C3;&#x30C8;/&#x30CA;&#x30CE;&#x30ED;&#x30C3;&#x30C9; &#x30D8;&#x30C6;&#x30ED;&#x69CB;&#x9020;&#x306E;&#x53EF;&#x80FD;&#x6027;&#x3092;&#x5B9F;&#x8A3C;&#x3059;&#x308B;&#x306B;&#x306F;&#x3001;&#x9AD8;&#x3044;&#x5185;&#x5FAE;&#x5C0F;&#x7403;&#x30EC;&#x30FC;&#x30B6;&#x30FC;&#x3067;&#x8D85;&#x4F4E;&#x30DD;&#x30F3;&#x30D7;&#x3057;&#x304D;&#x3044;&#x5024;&#x3092;&#x5C55;&#x793A;&#x3057;&#x307E;&#x3059;&#x3002;

&#x8D85;&#x4F4E;&#x3057;&#x304D;&#x3044;&#x5024; 2 &#x5149;&#x5B50;&#x52B1;&#x8D77;&#x306E; Ase &#x3068; Cd/&#x30B7;&#x30FC;&#x30C9; CdSe &#x30CA;&#x30CE;&#x30ED;&#x30C3;&#x30C9; &#x30D8;&#x30C6;&#x30ED;&#x69CB;&#x9020;&#x304B;&#x3089;&#x306E;&#x30EC;&#x30FC;&#x30B6;&#x30FC;&#x767A;&#x632F;&#x3057;&#x307E;&#x3059;&#x3002;

&#xCD08; &#xC784;&#xACC4;&#xAC12; 2 &#xAD11;&#xC790; &#xD38C;&#xD551; &#xC99D;&#xD3ED;&#xB41C; &#xC790;&#xBC1C; &#xBC29;&#xCD9C; (2ASE)&#xC640; &#xCC98;&#xC74C;&#xC73C;&#xB85C; &#xC2DC;&#xC5F0;&#xC740; &#xC2DC;&#xB4DC; CdSe/Cd nanodot/nanorod heterostructures&#xC744; lasing. &#xC774;&#xB7EC;&#xD55C; heterostructures &#xC218; &#xC788;&#xB3C4;&#xB85D; &#xB3C5;&#xB9BD;&#xC801;&#xC778; tunability 2 &#xAD11;&#xC790; &#xD761;&#xC218; (2PA) &#xD6A1;&#xB2E8;&#xBA74; (&sigma;(2)) Cd &#xB9C9;&#xB300; &#xD06C;&#xAE30; &#xBC0F; CdSe &#xB3C4;&#xD2B8; &#xD06C;&#xAE30; &#xBCC0;&#xD654;&#xB97C; &#xD1B5;&#xD574; &#xBC29;&#xCD9C; &#xD30C;&#xC7A5;&#xC758; &#xBCC0;&#xD654;&#xB97C; &#xD1B5;&#xD574;. &#xD5A5;&#xC0C1; &#xB41C; &sigma;(2)&#xC640; 2ase&#xC774;&#xC774; heterostructures&#xC5D0; &#xD544;&#xC694;&#xD55C; &#xAD6C;&#xD615; &#xBC18;&#xB3C4;&#xCCB4; NCs. &#xC911;&#xC694; &#xD55C; &#xAC83;&#xC740;, &#xBE44;&#xAD50;&#xC801; &#xD070; &#xB85C;&#xB4DC; &#xC5D0;&#xC11C;&#xB3C4; &#xAC15;&#xB825;&#xD55C; &#xC591;&#xC790; &#xAC10; &#xC804;&#xC2DC; &#xC2DC;&#xB4DC; nanorods&#xC758;&#xC774; &#xB3C5;&#xD2B9;&#xD55C; &#xC18D;&#xC131;&#xC744; &#xC774;&#xC6A9; &#xD558; &#xC5EC; &#xBCF4;&#xB2E4; &#xC791;&#xC740; &#xD06C;&#xAE30;, 2ASE &#xC784;&#xACC4;&#xAC12; &#xBC0F; 2PA &#xC561;&#xC158; &#xD6A1;&#xB2E8;&#xBA74; (&sigma;(2)&eta;) (&eta;&#xB294; &#xC591;&#xC790; &#xC218;&#xC728;) &#xBC1C;&#xACAC; &#xD588;&#xB2E4; &#xAC04; &#xADFC;&#xCC98; &#xC0C1;&#xD638; &#xAD00;&#xACC4; &#xB9CC;&#xD07C; &#xB9CE;&#xC774; &#xD55C; &#xC21C;&#xC11C;&#xB294; &sim;1.5 Mj/cm(2)&#xC758; ultralow &#xC784;&#xACC4;&#xAC12; fluence&#xB85C; &#xC774;&#xB8E8;&#xC5B4;&#xC9D1;&#xB2C8;&#xB2E4;. &#xADF8;&#xB9AC;&#xACE0; 2 &#xC138;-6 &#xC138; &#xBC18;&#xB3C4;&#xCCB4; nanostructures &#xC704;&#xD55C; &#xB113;&#xC740; &#xBCFC;&#xB968; &#xBC94;&#xC704;&#xC5D0; &#xB300;&#xD574; &#xC720;&#xD6A8;&#xC131;&#xC744; &#xAC80;&#xC0AC; &#xD569;&#xB2C8;&#xB2E4;. &#xCD08;&#xACE0;&#xC18D; &#xAD11;&#xD559; &#xBD84;&#xAD11;&#xD559;&#xC740; &#xC774;&#xB7EC;&#xD55C; heterostructures&#xC5D0; &#xB3C4;&#xB798; &#xD504;&#xB85C;&#xC138;&#xC2A4;&#xB294; &#xC2E4;&#xC81C;&#xB85C; &#xC5B5;&#xC81C; &#xD558;&#xB294; &#xB3D9;&#xC548; &#xC774;&#xB7EC;&#xD55C; &#xC0D8;&#xD50C;&#xC5D0;&#xC11C; ASE &#xC218;&#xB3C4; &#xAC15;&#xB825; &#xD558; &#xAC8C; &#xC801;&#xC6A9; &#xB420; &#xBE60;&#xB978; &#xAD6C;&#xBA4D; &#xD2B8;&#xB798;&#xD551; &#xD504;&#xB85C;&#xC138;&#xC2A4; NR &#xD45C;&#xBA74; &#xC0C1;&#xD0DC;&#xB97C; &#xD655;&#xC778; &#xD588;&#xC2B5;&#xB2C8;&#xB2E4;. &#xB9C8;&#xC9C0;&#xB9C9;&#xC73C;&#xB85C;, &#xB450; &#xAD11;&#xC790; lasing &#xB2EC;&#xC131;&#xC744; &#xC704;&#xD55C; &#xC2E4;&#xD589; &#xAC00;&#xB2A5;&#xD55C; &#xC774;&#xB4DD; &#xBBF8;&#xB514;&#xC5B4;&#xB85C; &#xC2DC;&#xB4DC; CdSe/Cd nanodot/nanorod heterostructures &#xC774;&#xB7EC;&#xD55C; &#xC7A0;&#xC7AC;&#xB825;&#xC744; &#xC608;&#xC99D; &#xD558;&#xB294; &#xB9E4;&#xC6B0; photostable microsphere &#xB808;&#xC774;&#xC800; ultralow &#xD38C;&#xD504; &#xC784;&#xACC4;&#xAC12;&#xC744; &#xAC16;&#xB294; &#xC804;&#xC2DC; &#xB429;&#xB2C8;&#xB2E4;.

Ultralow &#xC784;&#xACC4;&#xAC12; 2 &#xAD11;&#xC790; &#xD38C;&#xD551; &#xC99D;&#xD3ED;&#xB41C; &#xC790;&#xBC1C; &#xBC29;&#xCD9C; Lasing &#xC2DC;&#xB4DC; CdSe/Cd Nanorod Heterostructures&#xC5D0;&#xC11C;.

Ultralow umbral dos fotones bombea la emisi&oacute;n espont&aacute;nea amplificada (2ASE) y existencia en heteroestructuras de nanodot/nanorod de CdSe/CdS sembrados se demuestra por primera vez. Tales heteroestructuras permiten la afinabilidad independiente de la secci&oacute;n transversal de absorci&oacute;n de dos fotones (2PA) (&sigma;(2)) a trav&eacute;s de variar el tama&ntilde;o de la barra de CdS y de la longitud de onda de emisi&oacute;n a trav&eacute;s de variar el tama&ntilde;o de punto de CdSe. Con un &sigma;(2) mejorado, 2ASE en estos heteroestructuras se logra con un fluence de ultra bajo umbral de &sim;1.5 mJ/cm(2), que es tanto como un orden inferior al requerido para semiconductor esf&eacute;rico NCs. importante, aprovechando esta propiedad &uacute;nica de los sembrados nanorods exhibiendo confinamiento cu&aacute;ntico fuerte incluso en la barra de relativamente grande tama&ntilde;os, una cercana relaci&oacute;n rec&iacute;proca entre el umbral de la 2ASE y la secci&oacute;n de acci&oacute;n 2PA (&sigma;(2)&eta;) (donde &eta; es el rendimiento cu&aacute;ntico) encontraron y validado un rango amplio de nanoestructuras de semiconductores II-VI. Espectroscop&iacute;a &oacute;ptica ultrarr&aacute;pida hab&iacute;a verificado que mientras que los procesos de taladro en estos heteroestructuras de hecho se suprimen, ASE en estas muestras podr&iacute;a tambi&eacute;n ser afectado fuertemente por un r&aacute;pido proceso de agujero atrapan a los Estados de superficies NR. Por &uacute;ltimo, para ejemplificar el potencial de estos sembrados CdSe/CD nanodot/nanorod heteroestructuras como un medio de ganancia viable para lograr la existencia de dos fotones, se exhibe un altamente Fotoestables microesfera laser con un umbral de bomba ultra bajo.

Ultra bajo umbral dos fotones bombean emisi&oacute;n espont&aacute;nea amplificada y existencia de heteroestructuras sembrados CdSe/CD Nanorod.

We fabricated a single active layer quantum dot light-emitting diode device based on colloidal CdSe (core)/CdS (arm) tetrapod nanostructures capable of simultaneously producing room temperature electroluminesence (EL) peaks at two spectrally distinct wavelengths, namely, at ∼500 and ∼660 nm. This remarkable dual EL was found to originate from the CdS arms and CdSe core of the tetrapod architecture, which implies that the radiative recombination of injected charge carriers can independently take place at spatially distinct regions of the tetrapod. In contrast, control experiments employing CdSe-core-seeded CdS nanorods showed near-exclusive EL from the CdSe core. Time-resolved spectroscopy measurements on tetrapods revealed the presence of hole traps, which facilitated the localization and subsequent radiative recombination of excitons in the CdS arm regions, whereas excitonic recombination in nanorods took place predominantly within the vicinity of the CdSe core. These observations collectively highlight the role of morphology in the achievement of light emission from the different material components in heterostructured semiconductor nanoparticles, thus showing a way in developing a class of materials which are capable of exhibiting multiwavelength electroluminescence.

Dual wavelength electroluminescence from CdSe/CdS tetrapods.

Recent observations of excitonic coherences within photosynthetic complexes suggest that quantum coherences could enhance biological light harvesting efficiencies. Here, we employ optical pump-probe spectroscopy with few-femtosecond pulses to observe an excitonic quantum coherence in CdSe nanocrystals, a prototypical artificial light harvesting system. This coherence, which encodes the high-speed migration of charge over nanometer length scales, is also found to markedly alter the displacement amplitudes of phonons, signaling dynamics in the non-Born-Oppenheimer regime.

Observation of an Excitonic Quantum Coherence in CdSe Nanocrystals.

The salient optical properties of highly luminescent semiconductor nanocrystals render them ideal fluorophores for clinical diagnostics, therapeutics, and highly sensitive biochip applications. Microfluidic systems allow miniaturization and integration of multiple biochemical processes in a single device and do not require sophisticated diagnostic tools. Herein, we describe a microfluidic system that integrates RNA extraction, reverse transcription to cDNA, amplification and detection within one integrated device to detect histidine decarboxylase (HDC) gene directly from human white blood cells samples. When anisotropic semiconductor nanorods (NRs) were used as the fluorescent probes, the detection limit was found to be 0.4 ng of total RNA, which was much lower than that obtained using spherical quantum dots (QDs) or organic dyes. This was attributed to the large action cross-section of NRs and their high probability of target capture in a pull-down detection scheme. The combination of large scale integrated microfluidics with highly fluorescent semiconductor NRs may find widespread utility in point-of-care devices and multitarget diagnostics.

Gene Detection in Complex Biological Media Using Semiconductor Nanorods within an Integrated Microfluidic Device.

Nonclassical growth mechanisms such as self-assembly and oriented attachment are effective ways to build complex nanostructures from simpler ones. In the latter case, the nanoparticle components are electronically coupled; however, control over the attachment between nanoparticles is highly challenging and generally requires a delicate balance between dipole-, ligand-, and solvent-based interactions. To this end, we perform incomplete cation exchange with Ag(+) (Cu(+)) on CdSe-seeded CdS nanorods and tetrapods to exclusively convert their tips into small Ag2S (Cu2S) domains. Selective removal of the ligands from these inorganic domains results in spontaneous, site-specific bridging of the nanoparticles. Using this method, we demonstrate the fabrication of polymer-like linear and branched nanoparticles with enhanced electrical properties, as well as the stoichiometric formation of nanoparticle homo- and heterodimers and tetramers. We show that linked structures can then be completely cation exchanged with Pb(2+) to generate PbSe/PbS-based nanostructured photodetector media with enhanced properties.

Facet to Facet Linking of Shape Anisotropic Inorganic Nanocrystals with Site Specific and Stoichiometric Control.

There is a continuous demand for imaging probes offering excellent performance in various microscopy techniques for comprehensive investigations of cellular processes by more than one technique. Fluorescent nanodiamond-gold nanoparticles (FND-Au) constitute a new class of "all-in-one" hybrid particles providing unique features for multimodal cellular imaging including optical imaging, electron microscopy, and, and potentially even quantum sensing. Confocal and optical coherence microscopy of the FND-Au allow fast investigations inside living cells via emission, scattering, and photothermal imaging techniques because the FND emission is not quenched by AuNPs. In electron microscopy, transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) analysis of FND-Au reveals greatly enhanced contrast due to the gold particles as well as an extraordinary flickering behavior in three-dimensional cellular environments originating from the nanodiamonds. The unique multimodal imaging characteristics of FND-Au enable detailed studies inside cells ranging from statistical distributions at the entire cellular level (micrometers) down to the tracking of individual particles in subcellular organelles (nanometers). Herein, the processes of endosomal membrane uptake and release of FNDs were elucidated for the first time by the imaging of individual FND-Au hybrid nanoparticles with single-particle resolution. Their convenient preparation, the availability of various surface groups, their flexible detection modalities, and their single-particle contrast in combination with the capability for endosomal penetration and low cytotoxicity make FND-Au unique candidates for multimodal optical-electronic imaging applications with great potential for emerging techniques, such as quantum sensing inside living cells.

Fluorescent Nanodiamond-Gold Hybrid Particles for Multimodal Optical and Electron Microscopy Cellular Imaging.

Organelle-targeted photosensitization represents a promising approach in photodynamic therapy where the design of the active photosensitizer (PS) is very crucial. In this work, we developed a macromolecular PS with multiple copies of mitochondria-targeting groups and ruthenium complexes that displays highest phototoxicity toward several cancerous cell lines. In particular, enhanced anticancer activity was demonstrated in acute myeloid leukemia cell lines, where significant impairment of proliferation and clonogenicity occurs. Finally, attractive two-photon absorbing properties further underlined the great significance of this PS for mitochondria targeted PDT applications in deep tissue cancer therapy.

Mitochondria Targeted Protein-Ruthenium Photosensitizer for Efficient Photodynamic Applications.

We present a 3D time-lapse imaging method for monitoring mitochondrial dynamics in living HeLa cells based on photothermal optical coherence microscopy and using novel surface functionalization of gold nanoparticles. The biocompatible protein-based biopolymer coating contains multiple functional groups which impart better cellular uptake and mitochondria targeting efficiency. The high stability of the gold nanoparticles allows continuous imaging over an extended time up to 3000 seconds without significant cell damage. By combining temporal autocorrelation analysis with a classical diffusion model, we quantify mitochondrial dynamics and cast these results into 3D maps showing the heterogeneity of diffusion parameters across the whole cell volume.

3D Time-lapse Imaging and Quantification of Mitochondrial Dynamics.

We report a bioinspired multifunctional albumin derived polypeptide coating comprising grafted poly(ethylene oxide) chains, multiple copies of the HIV TAT derived peptide enabling cellular uptake as well as mitochondria targeting triphenyl-phosphonium (TPP) groups. Exploring these polypeptide copolymers for passivating gold nanoparticles (Au NPs) yielded (i) NIR-emitting markers in confocal microscopy and (ii) photo-thermal active probes in optical coherence microscopy. We demonstrate the great potential of such multifunctional protein-derived biopolymer coatings for efficiently directing Au NP into cells and to subcellular targets to ultimately probe important cellular processes such as mitochondria dynamics and vitality inside living cells.

Article	Year
pH-Responsive quantum dots via an albumin polymer surface coating. Journal of the American Chemical Society\| PubMed ID: 20302298	2010
Asymmetric dumbbells from selective deposition of metals on seeded semiconductor nanorods. Angewandte Chemie (International ed. in English)\| PubMed ID: 20306507	2010
Engineering fluorescence in Au-tipped, CdSe-seeded CdS nanoheterostructures. Small (Weinheim an der Bergstrasse, Germany)\| PubMed ID: 21990190	2011
Ultralow-Threshold Two-Photon Pumped Amplified Spontaneous Emission and Lasing from Seeded CdSe/CdS Nanorod Heterostructures. ACS nano\| PubMed ID: 23157595	2012
Dual wavelength electroluminescence from CdSe/CdS tetrapods. ACS nano\| PubMed ID: 24559396	2014
Observation of an Excitonic Quantum Coherence in CdSe Nanocrystals. Nano letters\| PubMed ID: 26359970	2015
Gene Detection in Complex Biological Media Using Semiconductor Nanorods within an Integrated Microfluidic Device. Analytical chemistry\| PubMed ID: 26382664	2015
Facet to Facet Linking of Shape Anisotropic Inorganic Nanocrystals with Site Specific and Stoichiometric Control. Nano letters\| PubMed ID: 27607441	2016
Fluorescent Nanodiamond-Gold Hybrid Particles for Multimodal Optical and Electron Microscopy Cellular Imaging. Nano letters\| PubMed ID: 27629492	2016
Mitochondria Targeted Protein-Ruthenium Photosensitizer for Efficient Photodynamic Applications. Journal of the American Chemical Society\| PubMed ID: 28097863	2017
3D Time-lapse Imaging and Quantification of Mitochondrial Dynamics. Scientific reports\| PubMed ID: 28230188	2017
NIR-emitting and photo-thermal active nanogold as mitochondria-specific probes. Biomaterials science\| PubMed ID: 28282092	2017

Sabyasachi Chakrabortty

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