The ability to upconvert two low energy photons into one high photon has potential applications in solar energy, biological imaging, and data storage. In this Letter, CdSe PbSe semiconductor nanocrystals are combined with molecular emitters (diphenylanthracene rubrene) both the visible near-infrared spectral regions. Absorption of by is followed transfer triplet states, which then undergo triplet–triplet annihilation create singlet states that emit upconverted light. By using conjugated...

Hybrid organic:inorganic materials composed of semiconductor nanocrystals functionalized with acene ligands have recently emerged as a promising platform for photon upconversion. Infrared light absorbed by nanocrystal excites charge carriers that can pass to surface-bound acenes, forming triplet excitons capable fusing produce visible radiation. To fully realize this scheme, energy transfer between and acenes must occur high efficiency, yet the mechanism process remains poorly understood....

We investigate triplet energy transfer (TET) across variable-length aromatic oligo-p-phenylene and aliphatic bridges in a covalently linked CdSe nanocrystal (NC)–bridge–anthracene hybrid system. Photon upconversion measurements saturated 9,10-diphenylanthracene hexane solutions under air-free conditions at room temperature provided the steady-state rate of TET (ket) this interface. For flexible transmitters, ket is similar for different lengths bridges, suggesting that ligands bend backward....

Abstract A sub‐monolayer CdS shell on PbS quantum dots (QDs) enhances triplet energy transfer (TET) by suppressing competitive charge from QDs to molecules. The increases the linear photon upconversion yield (QY) 3.5 % for 5.0 PbS/CdS when functionalized with a tetracene acceptor, 5‐CT . While transient absorption spectroscopy reveals that both and show formation of (with rates 5.91±0.60 ns −1 1.03±0.09 respectively), ultrafast hole occurs only Although decreases TET rate, it efficiency...

We designed and synthesized a tetracene derivative 4-(tetracen-5-yl)benzoic acid (CPT) as transmitter ligand used in PbS/PbSe nanocrystal (NC) sensitized upconversion of near infrared (NIR) photons. Under optimal conditions, comparing CPT functionalized NCs with unfunctionalized sensitizers, the quantum yield (QY) was enhanced 81 times for 2.9 nm PbS from 0.021% to 1.7%, 11 2.5 PbSe 0.20% 2.1%. The surface density controls solubility QY. By increasing concentration exchange solution, number...

Abstract Owing to the difficulty in comprehensively characterizing nanocrystal (NC) surfaces, clear guidance for ligand design is lacking. In this work, a series of bidentate bis(pyridine) anthracene isomers (2,3‐PyAn, 3,3‐PyAn, 2,2‐PyAn) that differ their binding geometries were designed find best complementary fit NC surface. The efficiency triplet energy transfer (TET) from CdSe donor diphenylanthracene (DPA) acceptor mediated by these was used as proxy efficacy orbital overlap and...

An overview of experimental and theoretical work on triplet energy transfer, with a focus transport in thin films.

Exciton exchange between semiconductor quantum dots (QDs) and organic chromophores may find application in next-generation photovoltaics, probes, or photocatalysts. We study the effect of shell composition thickness on triplet energy transfer (TET) from PbS QDs to rubrene a hybrid organic–inorganic photon upconverison system show that defect states introduced by surface adsorbed Zn Cd result up 700 325 fold enhancements yield (QY). Time-correlated single-photon counting, photoluminescence...

We study ligand exchange between the carboxylic acid group and 5.0 nm oleic-acid capped CdS nanocrystals (NCs) using fluorescence resonance energy transfer (FRET). This is first measurement of initial binding events cadmium chalcogenide NCs groups. The behavior can be described as an interaction a with single substrate multiple, identical sites. Assuming Poissonian statistics, our model fits both steady-state time-resolved photoluminescence (SSPL TRPL, respectively) data well. A modified...

Abstract A sub‐monolayer CdS shell on PbS quantum dots (QDs) enhances triplet energy transfer (TET) by suppressing competitive charge from QDs to molecules. The increases the linear photon upconversion yield (QY) 3.5 % for 5.0 PbS/CdS when functionalized with a tetracene acceptor, 5‐CT . While transient absorption spectroscopy reveals that both and show formation of (with rates 5.91±0.60 ns −1 1.03±0.09 respectively), ultrafast hole occurs only Although decreases TET rate, it efficiency...

This work describes the effects of pressure on photoluminescence Q-CdS (quantum-confined cadmium sulfide) nanoparticles stabilized by hexametaphosphate, calf thymus DNA, polyadenylic acid, polyuridylic and polyadenylic−uridylic acid in range from atmospheric to 4 kbar. A marked difference is observed between Q-CdS/polyadenylic that Q-CdS/polyuridylic terms pressure-induced changes luminescence; coating surface each type with hydroxide results a leveling effect whereby only steady diminution...

Abstract Owing to the difficulty in comprehensively characterizing nanocrystal (NC) surfaces, clear guidance for ligand design is lacking. In this work, a series of bidentate bis(pyridine) anthracene isomers (2,3‐PyAn, 3,3‐PyAn, 2,2‐PyAn) that differ their binding geometries were designed find best complementary fit NC surface. The efficiency triplet energy transfer (TET) from CdSe donor diphenylanthracene (DPA) acceptor mediated by these was used as proxy efficacy orbital overlap and...

Hybrid optoelectronic devices are attractive because they offer the promise of low-cost, roll-to-roll fabrication. Despite this, energy transfer between organic and inorganic interfaces is not well understood. Device engineering on this class solution-processed materials generally focuses replacing long insulating ligands with short ones. Here, we show that charge an nanocrystal (NC) donor molecular acceptor acutely sensitive to chemical moiety linking two species. Our results reveal CdS NCs...