University of Minnesota

Marie K Pomije

Kent R Mann

Larry L Miller

Yoshihito Kunugi

Christopher L Exstrom

Charles A Daws

Daron E Janzen

A sandwich-type, organic p-n junction photodiode is prepared by electrode-position of an insoluble layer of oligomerized tris(4-(2-thienyl)phenyl)amine onto conducting indium-tin oxide coated glass, spin-coating the stacked platinum compound, bis(cyanide)-bis(para-dodecylphenylisocyanide)platinum (II), from chloroform onto the oligomer layer, and then coating the platinum complex with a micro-array of aluminum electrodes by vapor deposition. This device shows rectification of current and gives a measurable photocurrent. The photocurrent action spectrum follows the absorption spectrum of the platinum complex; changes in the action spectrum with layer thickness point to a p-n junction formed at the interface of the molecular layers as the site of rectification. Exposure of the device to acetone vapor causes the action spectrum to shift dramatically to longer wavelength. Exposure to chloroform vapor causes a return to the original spectrum. These results demonstrate a new type of photosensor that reports the arrival of organic vapors.

Vapochromic photodiode

The present invention relates to a process for indicating the presence of organic vapors comprising the steps of determining the color, absorption or emission spectra of a Pt--Pt double-complex salt of platinum or a neutral platinum complex in the absence of organic vapor, exposing said double-complex salt of platinum or a neutral platinum complex to a gaseous environment, determining the color, absorption or emission spectra of said double-complex salt of platinum or a neutral platinum complex after exposure to said gaseous environment, and comparing the color, absorption and/or emission spectra of said double-complex salt of platinum or a neutral platinum complex in the absence of organic vapor with the color, absorption and/or emission spectra of said double-complex salt of platinum or a neutral platinum complex after exposure to said gaseous environment to determine if there is a difference in the color, absorption and/or emission spectra. The double-complex salt is represented by the general formulas �Pt(CN--C.sub.6 H.sub.4 -alkyl group).sub.4 !�PtX.sub.4 ! or �Pt(phen)(CN--C.sub.6 H.sub.4 -alkyl group).sub.2 !�PtX.sub.4 ! of �Pt(bpy)(CN--C.sub.6 H.sub.4 -alkyl group).sub.2 !�PtX.sub.4 ! and more preferably by the formulas �Pt(CN--C.sub.6 H.sub.4 --C.sub.n H.sub.2n+1).sub.4 !�Pt(CN).sub.4 ! or �Pt(phen)(CN--C.sub.6 H.sub.4 -alkyl group).sub.2 !�Pt(CN).sub.4 ! of �Pt(bpy)(CN--C.sub.6 H.sub.4 -alkyl group).sub.2 !�Pt(CN).sub.4 !, wherein n is a whole positive integer between 1 and 100. Still more preferably n is between 1 and 20. phen is 1,10-phenanthroline or an alkyl substituted phenanthroline, bpy is 2,2'-bipyridine or an alkyl substituted bipyridine. Other bidentate or tridentate amine ligands are also possible. The PtX.sub.4.sup.2- group can also be Pt(NO.sub.2).sub.4.sup.2-, Pt(Cl).sub.4.sup.2-, Pt(Br).sub.4.sup.2-, Pt(NCO).sub.4.sup.2-, Pt(NCS).sub.4.sup.2- or Pt(oxalate).sub.2.sup.2-. For the bpy and phen complexes, the palladium analogs of PtX.sub.4.sup.2- (ie. PdX.sub.4.sup.2- are also possible). The neutral complexes are represented by the general formulas Pt(CN--C.sub.6 H.sub.4 -alkyl group).sub.2 X.sub.2, and Pt(CN--C.sub.6 H.sub.4 -alkyl group)(C(Y).dbd.NH--C.sub.6 H.sub.4 -alkyl group)X.sub.2 wherein n is a whole positive integer between 1 and 100 and Y can be O-alkyl, NH-alkyl or N(alkyl).sub.2. Still more preferably n is between 1 and 20. The alkyl substituents may be different within the same complex. X is preferably CN.sup.-, but any other negatively charged groups such as NO.sub.2.sup.-, NCO.sup.-, NCS.sup.-, Cl.sup.-, Br.sup.-, I.sup.-, oxalate, etc. may also be used. The two X.sup.- groups are not necessarily the same.

Vapochromic platinum-complexes and salts

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Prior Lake, MN, United States of America

Marie K Pomije