Optische und photochemische versuche mit phosphor

Colossal Ultraviolet Photoresponsivity of Few-Layer Black Phosphorus

“…[1][2][3][11][12][13][14] Black phosphorus can be seen as a crystal generated by periodic repetition of tetraphosphorus (P 4 ) molecules. 15 It is known that tetraphosphorus P 4 can be transformed temporarily to diphosphorus P 2 upon ultraviolet (UV) irradiation, [16][17] which is often desirable because the latter form has a highly reactive π bond for many chemistry applications. [18][19][20] Thus, it is expected that the P 4 structured black phosphorus also has strong interaction with illumination especially the UV light.…”

“…[18][19][20] Thus, it is expected that the P 4 structured black phosphorus also has strong interaction with illumination especially the UV light. [16][17] Indeed, a black phosphorus based photodetector has been shown to have responsivity of 4.8 mAW -1 in the visible light regime 21 and its potential for fast imaging applications has also been demonstrated in both the visible light and near infrared regime. 12 Moreover, recent study reports an even higher responsivity (~10 2 mA/W) of black phosphorus based phototransistor in the visible light regime 22 through contact-engineering.…”

Functionalization of P4 through Direct P−C Bond Formation

“…Whereas reduction of P 4 by means of cyclic voltammetry (CV) occurs readily, it is irreversible due to bond rupture and polymerization of the formed radical anion (P 4 .− ) . White phosphorus can also be “cracked” both thermally (>1100 K) and photochemically (UV irradiation) into two transient P 2 molecules (P≡P) that polymerize rapidly to the more stable red phosphorus allotrope …”

“…[5b, 12] White phosphorus can also be "cracked" both thermally (> 1100 K) [13] and photochemically (UV irradiation) [14] into two transient P 2 molecules (PP) that polymerize rapidly to the more stable red phosphorus allotrope. [15] In this Minireview we highlight recent breakthroughs in P 4 chemistry by focusingo nr eactions that directly create PÀC bondsw ith main group and transition metal organyls, ambiphilic carbenes,a nd carboradicals as well as on trapping of P 2 fragments with organic substrates.…”

PP, ein Laborreagens?

“…Es wurde gezeigt, dass ein Gleichgewicht zwischen P 2 und P 4 existiert, wenn auch erst unter extremen Bedingungen, etwa bei Temperaturen über 800 8C und niedrigen Drücken. Bei Atmosphärendruck erreicht die Dissoziation von P 4 auf die oben beschriebene Studie faszinierend zu erfahren, ob diese Arbeiten bezüglich der Bildung von freiem P 2 als Schlüsselintermediat neu interpretiert werden können. In diesem Zusammenhang ist auch eine etwas andere Methode zur Stabilisierung der P 2 -Einheit bemerkenswert, bei der P 2 durch Singulett-Carbene abgefangen wird.…”