arsenic precursor [2,16] besides the less reactive tris(trimethylgermyl)arsane (As(GeMe 3 ) 3 ) [17] or highly toxic arsine gas (AsH 3 ). [18] Recently, Srivastava et al. [19] and Grigel et al. [20] highlighted tris(dimethylamino)arsane (As(NMe 2 ) 3 ) as commercially available pre cursor for the facile synthesis of InAs QDs. Mechanistically, As(NMe 2 ) 3 undergoes a transamination reaction with the solvent and reagent oleylamine (OLAH) to give trioleyl arsane (As(OLA) 3 ) under the release of three equivalents of flammable dimethylamine. The reaction of As(OLA) 3 with indium(III) chloride (InCl 3 ) to InAs QDs does not proceed without the subsequent addition of a reducing agent for which typically diisobutylaluminum hydride (DIBALH) [19] and nowadays also trioleylphosphane (P(OLA) 3 ) [20] or a N,Ndimethylethylamine com plex (DMEAAlH 3 ) [21] are used. In the case of DIBALH and DMEA AlH 3 , the As-N bonds are cleaved to give in situ (OLA) x AsH 3x species which react with the indium precursor to InAs QDs. [22,23] With the applied concentration of DIBALH the size of InAs QDs can be tuned according to the method by Srivastava et al. [19] By contrast, the approach by Grigel et al. [20] applies in situ generated P(OLA) 3 as reducing agent for the InAs QD synthesis (Scheme 1). This species is known to act both, as a remarkably efficient phos phorus precursor and reducing agent for the preparation of InP QDs. [24][25][26] Grigel et al. [20] pointed out that phase pure InAs QDs are obtained since P(OLA) 3 only provides the electrons required for the reduction of As(OLA) 3 to InAs (Scheme 1).In previous work we introduced tripyrazolylphosphanes (P(pyr) 3 , e.g., pyr = 3,5dimethylpyrazole, 2) for the convenient preparation of a long term stable (>6 months) P(OLA) 3 stock solution and its application for the synthesis of highly emitting InP/ZnS QDs. [5,6] Derivatives of P(pyr) 3 are accessible on a multigram scale and represent a safe to handle, less toxic sur rogate for cancerogenic hexaalkylphosphorous triamide deriva tives such as trisdimethylaminophosphane (P(NMe 2 ) 3 ) and tris diethylaminophosphane (P(NEt 2 ) 3 ). Moreover, the release of cor rosive, flammable, and gaseous dialkylamines (Me 2 NH, Et 2 NH) during the transamination with OLAH is prevented. The released pyrazoles can easily be recovered in high yields (>94%) and reused for the precursor synthesis. The tripyrazolylarsane (As(pyr) 3 , e.g., pyr = 3,5dimethylpyrazole, 1) analogues are envisioned to react similarly, thus, representing a convenient to handle and stable arsenic precursor for the InAs QD synthesis. Tris(3,5-dimethylpyrazolyl)arsane (1) is introduced as a low-cost and convenient to handle arsenic precursor for the straight forward synthesis of InAs quantum dots (QDs). Transamination of 1 with the solvent oleylamine (OLAH) gives trioleylarsane (As(OLA) 3 ) which in the presence of the reducing agents diisobutylaluminum hydride (DIBAL-H) or trioleylphosphane (P(OLA) 3 ) yields InAsQDs via a typical hot injection approach. The size of the obtain...

Tri(pyrazolyl)phosphanes (5 ) are utilized as an alternative, cheap and low-toxic phosphorus source for the convenient synthesis of InP/ZnS quantum dots (QDs). From these precursors, remarkably long-term stable stock solutions (>6 months) of P(OLA) (OLAH=oleylamine) are generated from which the respective pyrazoles are conveniently recovered. P(OLA) acts simultaneously as phosphorus source and reducing agent in the synthesis of highly emitting InP/ZnS core/shell QDs. These QDs are characterized by a spectral range between 530-620 nm and photoluminescence quantum yields (PL QYs) between 51-62 %. A proof-of-concept white light-emitting diode (LED) applying the InP/ZnS QDs as a color-conversion layer was built to demonstrate their applicability and processibility.

Tri(pyrazolyl)phosphane werden als alternative kostengünstige und weniger toxische Phosphorquelle in der Synthese von InP/ZnS‐Quantenpunkten (QDs) eingesetzt. Ausgehend von ihnen können langzeitstabile (>6 Monate) P(OLA)3‐Stammlösungen (OLAH=Oleylamin) synthetisiert werden, aus denen sich die entsprechenden Pyrazole einfach zurückgewinnen lassen. P(OLA)3 fungiert in der Synthese von stark emittierenden InP/ZnS‐QDs sowohl als Phosphorquelle als auch als Reduktionsmittel. Die erhaltenen Kern/Schale‐Partikel zeichnen sich durch hohe Photolumineszenz‐Quantenausbeuten von 51–62 % in einem Spektralbereich von 530–620 nm aus. Die Verarbeitung und Anwendung dieser InP/ZnS‐QDs als Farbkonversionsschicht wurde anhand des Einsatzes in einer weißen Leuchtdiode demonstriert.